Cleaning chemistry – the awesome power of soap

Well, times are interesting at the moment, aren’t they? I’m not going to talk (much) about The Virus (there’s gonna be a movie, mark my words), because everyone else is, and I’m not an epidemiologist, virologist or an immunologist or, in fact, in any way remotely qualified. I am personally of the opinion that it’s not even especially helpful to talk about possibly-relevant drugs at the moment, given that we don’t know enough about possible negative interactions, and we don’t have reliable data about the older medicines being touted.

In short, I think it’s best I shut up and leave the medical side to the experts. But! I DO know about something relevant. What’s that, I hear you ask? Well, it’s… soap! But wait, before you start yawning, soap is amazing. It is fascinating. It both literally and figuratively links loads of bits of cool chemistry with loads of other bits of cool chemistry. Stay with me, and I’ll explain.

First up, some history (also not a historian, but that crowd is cool, they’ll forgive me) soap is old. Really, really, old. Archaeological evidence suggests ancient Babylonians were making soap around 4800 years ago – probably not for personal hygiene, but rather, mainly, to clean cooking pots. It was originally made from fats boiled with ashes, and the theory generally goes that the discovery was a happy accident: ashes left from cooking fires made it much easier to clean pots and, some experimenting later, we arrived at something we might cautiously recognise today as soap.

Soap was first used to clean pots.

The reason this works is that ashes are alkaline. In fact, the very word “alkali” is derived from the Arabic al qalīy, meaning calcined ashes. This is because plants, and especially wood, aren’t just made up of carbon and hydrogen. Potassium and calcium play important roles in tree and plant metabolism, and as a result both are found in moderately significant quantities in wood. When that wood is burnt at high temperatures, alkaline compounds of potassium and calcium form. If the temperature gets high enough, calcium oxide (lime) forms, which is even more alkaline.

You may, in fact, have heard the term potash. This usually refers to salts that contain potassium in a water-soluble form. Potash was first made by taking plant ashes and soaking them in water in a pot, hence, “pot ash”. And, guess where we get the word potassium from? Yep. The pure element, being very reactive, wasn’t discovered until 1870, thousands of years after people first discovered how useful its compounds could be. And, AND, why does the element potassium have the symbol K? It comes from kali, the root of the word alkali.

See what I mean about connections?

butyl ethanoate butyl ethanoate

Why is the fact that the ashes are alkaline relevant? Well, to answer that we need to think about fats. Chemically, fats are esters. Esters are chains of hydrogen and carbon that have, somewhere within them, a cheeky pair of oxygen atoms. Like this (oxygen atoms are shown red):

Now, this is a picture of butyl ethanoate (aka butyl acetate – smells of apples, by the way) and is a short-ish example of an ester. Fats generally contain much longer chains, and there are three of those chains, and the oxygen bit is stuck to a glycerol backbone.

Thus, the thick, oily, greasy stuff that you think of as fat is a triglyceride: an ester made up of three fatty acid molecules and glycerol (aka glycerine, yup, same stuff in baking). But it’s the ester bit we want to focus on for now, because esters react with alkalis (and acids, for that matter) in a process called hydrolysis.

Fats are esters. Three fatty acid chains are attached to a glycerol “backbone”.

The clue here is in the name – “hydro” suggesting water – because what happens is that the ester splits where those (red) oxygens are. On one side of that split, the COO group of atoms gains a metal ion (or a hydrogen, if the reaction was carried out under acidic conditions), while the other chunk of the molecule ends up with an OH on the end. We now have a carboxylate salt (or a carboxylic acid) and an alcohol. Effectively, we’ve split the molecule into two pieces and tidied up the ends with atoms from water.

Still with me? This is where it gets clever. Having mixed our fat with alkali and split our fat molecules up, we have two things: fatty acid salts (hydrocarbon chains with, e.g. COONa+ on the end) and glycerol. Glycerol is extremely useful stuff (and, funnily enough, antiviral) but we’ll put that aside for the moment, because it’s the other part that’s really interesting.

What we’ve done here is produce a molecule that has a polar end (the charged bit, e.g. COONa+) and a non-polar end (the long chain of Cs and Hs). Here’s the thing: polar substances tend to only mix with other polar substances, while non-polar substances only mix with other non-polar substances.

You may be thinking this is getting technical, but honestly, it’s not. I guarantee you’ve experienced this: think, for example, what happens if you make a salad dressing with oil and vinegar (which is mostly water). The non-polar oil floats on top of the polar water and the two won’t stay mixed. Even if you give them a really good shake, they separate out after a few minutes.

The dark blue oily layer in this makeup remover doesn’t mix with the watery colourless layer.

There are even toiletries based around this principle. This is an eye and lip makeup remover designed to remove water-resistant mascara and long-stay lipstick. It has an oily layer and a water-based layer. To use it, you give the container a good shake and use it immediately. The oil in the mixture removes any oil-based makeup, while the water part removes anything water-based. If you leave the bottle for a minute or two, it settles back into two layers.

But when we broke up our fat molecules, we formed a molecule which can combine with both types of substance. One end will mix with oily substances, and the other end mixes with water. Imagine it as a sort of bridge, joining two things that otherwise would never be connected (see, literal connections!)

There are a few different names for this type of molecule. When we’re talking about food, we usually use “emulsifier” – a term you’ll have seen on food ingredients lists. The best-known example is probably lecithin, which is found in egg yolks. Lecithin is the reason mayonnaise is the way it is – it allows oil and water to combine to give a nice, creamy product that stays mixed, even if it’s left on a shelf for months.

When we’re talking about soaps and detergents, we call these joiny-up molecules “surfactants“. You’re less likely to have seen that exact term on cosmetic ingredients lists, but you will (if you’ve looked) almost certainly have seen one of the most common examples, which is sodium laureth sulfate (or sodium lauryl sulfate), because it turns up everywhere: in liquid soap, bubble bath, shampoo and even toothpaste.

I won’t get into the chemical makeup of sodium laureth sulfate, as it’s a bit different. I’m going to stick to good old soap bars. A common surfactant molecule that you’ll find in those is sodium stearate, which is just like the examples I was talking about earlier: a long hydrocarbon chain with COONa+ stuck on the end. The hydrocarbon end, or “tail”, is hydrophobic (“water-hating”), and only mixes with oily substances. The COONa+ end, or “head”, is hydrophilic (“water loving”) and only mixes with watery substances.

Bars of soap contain sodium stearate.

This is perfect because dirt is usually oily, or is trapped in oil. Soap allows that oil to mix with the water you’re using to wash, so that both the oil, and anything else it might be harbouring, can be washed away.

Which brings us back to the wretched virus. Sars-CoV-2 has a lipid bilayer, that is, a membrane made of two layers of lipid (fatty) molecules. Virus particles stick to our skin and, because of that membrane, water alone does a really bad job of removing them. However, the water-hating tail ends of surfacant molecules are attracted to the virus’s outer fatty surface, while the water-loving head ends are attracted to the water that’s, say, falling out of your tap. Basically, soap causes the virus’s membrane to dissolve, and it falls apart and is destroyed. Victory is ours – hurrah!

Hand sanitisers also destroy viruses. Check out this excellent Compound Interest graphic (click the image for more).

Who knew a nearly-5000 year-old weapon would be effective against such a modern scourge? (Well, yes, virologists, obviously.) The more modern alcohol hand gels do much the same thing, but not quite as effectively – if you have access to soap and water, use them!

Of course, all this only works if you wash your hands thoroughly. I highly recommend watching this video, which uses black ink to demonstrate what needs to happen with the soap. I thought I was washing my hands properly until I watched it, and now I’m actually washing my hands properly.

You may be thinking at this point (if you’ve made it this far), “hang on, if the ancient Babylonians were making soap nearly 5000 years ago, it must be quite easy to make… ooh, could I make soap?!” And yes, yes it is and yes you can. Believe me, if the apocolypse comes I shall be doing just that. People rarely think about soap in disaster movies, which is a problem, because without a bit of basic hygine it won’t be long before the hero is either puking his guts up or dying from a minor wound infection.

Here’s the thing though, it’s potentially dangerous to make soap, because most of the recipes you’ll find (I won’t link to any, but a quick YouTube search will turn up several – try looking for “saponification“) involve lye. Lye is actually a broad term that covers a couple of different chemicals, but most of the time when people say lye these days, they mean pure sodium hydroxide.

Pure sodium hydroxide is usually supplied as pellets.

Pure sodium hydroxide comes in the form of pellets. It’s dangerous for two reasons. Firstly, precisely because it’s so good at breaking down fats and proteins, i.e. the stuff that humans are made of, it’s really, really corrosive and will give you an extremely nasty burn. Remember that scene in the movie Fight Club? Yes, that scene? Well, that. (Follow that link with extreme caution.)

And secondly, when sodium hydroxide pellets are mixed with water, the solution gets really, really hot.

It doesn’t take a lot of imagination to realise that a really hot, highly corrosive, solution is potentially a huge disaster waiting to happen. So, and I cannot stress this enough, DO NOT attempt to make your own soap unless you have done a lot of research AND you have ALL the appropriate safety equipment, especially good eye protection.

And there we are. Soap is ancient and awesome, and full of interesting chemistry. Make sure you appreciate it every time you wash your hands, which ought to be frequently!

Stay safe, everyone. Take care, and look after yourselves.


Want something non-sciency to distract you? Why not check out my fiction blog: the fiction phial. There are loads of short stories, and even (recently) a poem. Enjoy!

If you’re studying from home, have you got your Pocket Chemist yet? Why not grab one? It’s a hugely useful tool, and by buying one you’ll be supporting this site – it’s win-win!

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Black Salve BS

Historically, people weren’t always careful in the sun.

Summer is fast disappearing in the Northern hemisphere and with it, the sunshine. Which is sad, as we all love a bit of sun, don’t we? Even if it doesn’t always love us, particularly those of us with fairer skin. Sunburn is no fun, but these days we also understand that it’s worse than a couple of days of painfully peeling skin: too much sun exposure can cause cancer.

Unfortunately there’s a whole generation – indeed more than one – who didn’t grow up with parents constantly slathering on the factor 50 (easy-to-use transparent sunscreens with very high SPFs didn’t appear on the market until the 1990s). For some sunburn was a regular part of summer, and those people need to be particularly vigilant for changes which might signify something nasty is going on.

On the plus side, these types of cancer are very treatable, and the outlook is hopeful. Often, the growth can be removed by surgery or even cryotherapy with very little scarring. Even the most dangerous kind of skin cancer, malignant melanoma, has a ten-year survival rate of around 90% with appropriate treatment.

But there’s the key: appropriate treatment. If you notice changes in your skin, especially a mole which is changing in colour or shape, you must see a qualified doctor as soon as you can.

What you should absolutely not do is visit the Black Salve page on Facebook (which I am not linking to for reasons which will be come obvious). This page, so Facebook tells me, is followed by nearly 17,000 users. It features a cheery cover photo of a family holding a canoe over their heads, and its profile picture is a pretty white and yellow flower.

Sanguinarine is a toxic salt extracted from the bloodroot plant. It’s infamous for its ability to destroy animal cells.

It’s all very suggestive of a homely, traditional remedy. The sort of thing your grandma had in her medicine cabinet. Very safe and “natural“. But while black salve might be a traditional remedy, it is anything but safe. Most preparations contain bloodroot, a source of the toxin sanguinarine, which kills animal cells.

Applying bloodroot to the skin destroys tissues and causes the formation of a large, black lump of dead flesh. Eventually this mass, called an eschar, falls off, leaving varying degrees of damage behind (internal use is also not recommended: consuming bloodroot can cause vomiting and loss of consciousness).

Bloodroot is easy to buy. Back in May this year the Good Thinking Society reported that eBay had removed “listings for dangerous cancer ‘cure’” following an investigation. Those listings were for black salve, and this was, of course, very positive news. Except for one thing: whilst listings for black salve were removed (and remain absent), listings for bloodroot were not. At the time of writing, a quick search reveals several bloodroot preparations still for sale.

At the time of writing, bloodroot is easy to find on eBay. The listing confirms that this is prepared from the “rhizome of certified organically grown Sanguinaria conadensis plants”.

Why is this such a bad thing? Because it’s easy to find recipes for making homemade black salve with bloodroot online, and using such mixtures can have truly horrific consequences. Last year the story of a woman who applied it to a basal cell carcinoma on her nose was widely reported. The black salve paste she used did so much damage that she ended up with a large hole in her nose through which she could actually draw air. Photos and video are available online (be warned: it’s gruesome).

Many patients turn to black salve as an alternative to what they imagine will be disfiguring surgery to treat their cancer. But, as in this woman’s case, the paste can do so much damage that far more extensive, reconstructive, surgery is ultimately needed.

Black Salve usually contains bloodroot and, sometimes, zinc chloride – another skin irritant.

It won’t surprise anyone to learn that dermatologists don’t recommend black salve. It can do enormous damage to the surface of the skin, resulting in scarring and a high risk of infection, and it does kill cancer cells along the way. But there is no guarantee that all of the cancerous cells deep within the skin will be destroyed. As a result, patients who’ve attempted to cure themselves may end up with cancerous tissue hidden, and growing, beneath a scar.

In fact, exactly this happened to an otherwise healthy 76 year-old woman in 2006. Her case is described in detail in the journal Dermatology Practical Conceptual – in summary, she refused surgery on a small melanoma on her leg. Instead, she bought black salve on the internet and applied it. A few years later the cancer had spread to her lungs, liver and lymph nodes.

Some people even recommend using black salve on breast cancers but this is, if possible, even worse. It’s highly unlikely that the salve will reach the entirety of a tumour which is beneath the skin. It is likely to do some horribly painful and disfiguring damage along the way, though.

Black salve is particularly popular in Australia, which of course has some of the highest rates of skin cancer in the world. But it’s available in the UK too. One online “herbal medicine” site is openly selling various formulations at prices ranging from £25-£100. Ironically, they describe their “Herbactive” product as “chemical free” (it isn’t, nothing is) and then go onto boast that it “now has a stronger concentration of bloodroot”. Fantastic.

They also sell a product which contains zinc chloride along with bloodroot. They claim zinc chloride is safe. It isn’t. It’s well-known to be a skin irritant, and should never be left in contact with skin.

The Black Salve Facebook page is full of anecdotes and testimonials, but light on evidence.

The Black Salve Facebook page is packed full of anecdotes and testimonials from people who claim to have used these mixtures safely. It’s all interspersed, of course, with the usual “Big Pharma” conspiracy theories. Namely, that the “truth” is being suppressed because there’s “no money in it for the pharmaceutical [industry].”

The irony is that reconstructive surgery is incredibly expensive, and the antibiotics, painkillers and other drugs that are inevitably needed to treat black salve victims aren’t free, either.

Given that Facebook’s community standards page states that: “We remove content, disable accounts and work with law enforcement when we believe that there is a genuine risk of physical harm or direct threats to public safety.” one has to wonder why the Black Salve page is still there. People are actually posting pictures of physical harm. What more does Facebook need?

Please, don’t be tempted to use black salve, or anything containing bloodroot. If you think you have a skin tumour see a properly qualified doctor and follow his or her advice.

It might literally save your life.


Like the Chronicle Flask’s Facebook page for regular updates, or follow @chronicleflask on Twitter. All content is © Kat Day 2017. You may share or link to anything here, but you must reference this site if you do.


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The Chronicles of the Chronicle Flask: 2016

2016 is limping to its painful conclusion, still tossing out last-minute nasty surprises like upturned thumb tacks in the last few metres of a marathon. But the year hasn’t been ALL bad. Some fun, and certainly interesting, things happened too. No, really, they did, honestly.

So with that in mind, let’s have a look back at 2016 for the Chronicle Flask….

January kicked off with a particularly egregious news headline in a well-known broadsheet newspaper: Sugar found in ketchup and Coke linked to breast cancer. Turns out that the sugar in question was fructose. Yes, the sugar that’s in practically everything, and certainly everything that’s come from a plant. So why did the newspaper in question choose ketchup and Coke for their headline instead of, oh, say, fruit juice or honey? Surely not just in an effort to sell a few more newspapers after the overindulgent New Year celebrations. Surely.

octarineThere was something more lighthearted to follow when IUPAC  verified the discoveries of elements 113, 115, 117 and 118. This kicked off lots of speculation about the elements’ eventual names, and the Chronicle Flask suggested that one of them should be named Octarine in honour of the late Sir Terry Pratchett. Amazingly, this suggestion really caught everyone’s imagination. It was picked up in the national press, and the associated petition got over 51 thousand signatures!

In February I wrote a post about the science of statues, following the news that a statue to commemorate Sir Terry Pratchett and his work had been approved by Salisbury City Council. Did you know that there was science in statues? Well there is, lots. Fun fact: the God of metalworking was called Hephaestus, and the Greeks placed dwarf-like statues of him near their Hearths – could this be where the fantasy trope of dwarves as blacksmiths originates?

MCl and MI are common preservatives in cosmetic products

MCl and MI are common preservatives in cosmetic products

My skeptical side returned with a vengeance in March after I read some online reviews criticising a particular shampoo for containing a substance known as methylchloroisothiazolinone. So should you be scared of your shampoo? In short, no. Not unless you have a known allergy or particularly sensitive skin. Otherwise, feel free to the pick your shampoo based on the nicest bottle, the best smell, or the forlorn hope that it will actually thicken/straighten/brighten your hair as promised, even though they never, ever, ever do.

Nature Chemistry published Another Four Bricks in the Wall in April – a piece all about the potential names of new elements, partly written by yours truly. The month also brought a sinus infection. I made the most of this opportunity by writing about the cold cure that’s 5000 years old. See how I suffer for my lovely readers? You’re welcome.

In May I weighed in on all the nonsense out there about glyphosate (and, consequently, learned how to spell and pronounce glyphosate – turns out I’d been getting it wrong for ages). Is it dangerous? Nope, not really. The evidence suggests it’s pretty harmless and certainly a lot safer than most of its alternatives.

may-facebook-postSomething else happened in May: the Chronicle Flask’s Facebook page received this message in which one of my followers told me that my post on apricot kernels had deterred his mother from consuming them. This sort of thing makes it all worthwhile.

In June the names of the new elements were announced. Sadly, but not really very surprisingly, octarine was not among them. But element 118 was named oganesson and given the symbol Og. Now, officially, this was in recognition of the work of Professor Yuri Oganessian, but I for one couldn’t help but see a different reference. Mere coincidence? Surely not.

July brought another return to skepticism. This time, baby wipes, and in particular a brand that promise to be “chemical-free”. They’re not chemical-free. Nothing is chemical-free. This is a ridiculous label which shouldn’t be allowed (and yet, inexplicably, is still in use). It’s all made worse by the fact that Water Wipes contain a ‘natural preservative’ called grapefruit seed extract which, experiments have shown, only actually acts as a preservative when it’s contaminated with synthetic substances. Yep. Turns out some of Water Wipes claims are as stinky as the stuff they’re designed to clean up.

Maria Lenk Aquatic Enter, Tuesday, Aug. 9, 2016. (AP Photo/Matt Dunham)

Maria Lenk Aquatic Enter, Tuesday, Aug. 9, 2016. (AP Photo/Matt Dunham)

August brought the Olympics, and speculation was rife about what, exactly, was causing the swimming pools to turn such strange shades of green. Of course, the Chronicle Flask knew the correct solution…

August also saw MMS and CD reared their ugly heads on social media again. CD (chlorine dioxide) is, lest we forget, a type of bleach solution which certain individuals believe autistic children should be made to drink to ‘cure’ them. Worse, they believe such children should be forced to undergo daily enemas using CD solutions. I wrote a summary page on MMS (master mineral solution) and CD, as straight-up science companion to the commentary piece I wrote in 2015.

mugsSeptember took us back to pesticides, but this time with a more lighthearted feel. Did you know that 99.99% of all the pesticides you consume are naturally-occurring? Well, you do if you regularly read this blog. The Chronicle Flask, along with MugWow, also produced a lovely mug. It’s still for sale here, if you need a late Christmas present… (and if you use the code flask15 you’ll even get a discount!)

In October, fed up with endless arguments about the definition of the word ‘chemical’ I decided to settle the matter once and for all. Kind of. And following that theme I also wrote 8 Things Everyone Gets Wong About ‘Scary’ Chemicals for WhatCulture Science.

Just in case that wasn’t enough, I also wrote a chapter of a book on the missing science of superheroes in October. Hopefully we should see it in print in 2017.

Sparklers are most dangerous once they've gone out.

Sparklers are most dangerous once they’ve gone out.

I decided to mark Fireworks Night in November by writing about glow sticks and sparklers. Which is riskier? The question may not be as straightforward as you’d imagine. This was followed by another WhatCulture Science piece, featuring some genuinely frightening substances: 10 Chemicals You Really Should Be Scared Of.

And that brings us to December, and this little summary. I hope you’ve enjoyed the blog this year – do tell your friends about it! Remember to follow @ChronicleFlask on Twitter and like fb.com/chronicleflask on Facebook – both get updated more or less daily.

Here’s wishing all my lovely readers a very Happy New Year – enjoy a drop of bubbly ethanol solution and be careful with the Armstrong’s mixture…. 

See you on the other side!

new-year-1898553_960_720

Do you really need to worry about baby wipes?

Never mind ingredients, just give me a packet that's not empty!

Never mind ingredients, just give me a packet that’s not empty!

A little while back I wrote a post about shampoo ingredients, and in passing I mentioned baby wipes. Now, these are one of those products which you’ve probably never bought if you’re not a parent, but as soon as you are you find yourself increasingly interested in them. Yes, I know, reusable ‘wipes’ are a thing. But after dealing with a nappy explosion at 2am in the morning, I’m willing to bet that more than one parent’s environmental conscience has gone in the rubbish bin along with a bag of horror they never want to see again, at least for a little while.

But which wipes to buy? The cheapest ones? The nicest-smelling ones? The fragrance-free ones? The ones with the plastic dispenser on the top that allow you to easily grab one wipe at a time? Or not, because those bulky dispensers produce yet more plastic waste? Or just whichever brand you grabbed first at the all-night supermarket at some unpleasant hour that’s too late to be night yet too early to be morning?

All of the above at one time or another, probably. However, I’m going to suggest that one thing you can stop worrying about right now is whether or not your wipes are labelled ‘chemical-free’.

As I’ve explained before, everything is made up of chemicals. By any sensible definition, water is a chemical, and thus the claim that Water Wipes® (“the world’s purest baby wipe”) are “chemical free” is simply incorrect.

These wipes are not, actually, chemical-free.

These wipes are not, actually, chemical-free.

In fact, Water Wipes® aren’t even, as you might imagine, made of some sort of non-woven fabric impregnated with plain water. No, they contain something else: grapefruit seed extract.

Well, that sounds natural, I hear you say. It does, doesn’t it? Grapefruit, that sounds fresh. Seed, well seeds are healthy, aren’t they? And the word ‘extract’ is very natural-sounding. What’s the problem?

Let’s start with what grapefruit seed extract, also called GSE, actually is. It’s made from the seeds, pulp and white membranes of grapefruit. These ingredients are ground up and a drop of glycerin is added. Glycerin, by the way, is otherwise known as glycerol, or propane-1,2,3-triol. It’s naturally-occurring – it’s one of the molecules you get when you break up fats – and it’s usually made from plants such as soybeans or palm (uh oh…), or sometimes from tallow (oh dear…) or as a byproduct of the petroleum industry (yikes! – I wonder if the manufacturers of Water Wipes® enquired about the nature of the glycerin being added to their product…?)

But anyway, back to GSE. Like all plant extracts, grapefruit seed extract is stuffed full of other chemicals that occur naturally. In particular, flavonoids, ascorbic acid (vitamin C), tocopherols, citric acid, limonoids and sterols.

citric acid synthetic vs natural

Can you tell the difference?

So… in short, not chemical-free at all. Not even a bit. The problem here is that, in marketing, the term ‘chemical-free’ is used to mean something that only contains ingredients from ‘natural’ sources. But this is meaningless. Take citric acid, for example. (E330 by the way – E numbers don’t mean something’s deadly, either. In fact, quite the opposite.) There’s no difference between citric acid extracted from a grapefruit and citric acid prepared in a laboratory. They both have exactly the same atoms and the same molecular formula and structure. They both react in the same way.

They’d both be classified as corrosive in high concentrations, and irritant in low concentrations. This isn’t even “might” cause irritation. This is absolutely, definitely, positively WILL cause irritation.

Wait, hang on a minute! There’s a potentially corrosive chemical in the ‘chemical-free’ baby wipes, and unsuspecting parents are putting it on their baby’s skin?!

Yep.

But before anyone runs off to write the next Daily Mail headline, let’s be clear. It’s really not going to burn, alien acid-style, through a new baby’s skin. It’s not even going to slightly redden a baby’s skin, because the quantity is so miniscule that it quite literally has no corrosive properties at all. It’s the same logic as in the old adage that “the dose makes the poison“.

This is where we, as consumers, ought to stop and think. If a fraction of a drop of citric acid is harmless then…. perhaps that small quantity of PEG 40 hydrogenated castor oil or sodium benzoate in most (considerably less expensive, I’m just saying) other brands of baby wipes isn’t as awful as we thought, either…

Indeed, it’s not. But what sodium benzoate in particular IS, is a very effective preservative.

Grapefruit seed extract is marketed as a natural preservative, but studies haven't backed up this claim.

Grapefruit seed extract is allegedly a natural preservative, but studies haven’t backed up this claim.

Why does this matter? Well, without some sort of preservative baby wipes, which sit in a moist environment for weeks or months or even years, might start to grow mould and other nasties. You simply can’t risk selling packets of water-soaked fabric, at a premium price, without any preservative at all, because one day someone might open one of those packets and find it full of mould. At which point they would, naturally, take a photo and post it all over social media. Dis-as-ter.

This is why Water Wipes® include grapefruit seed extract, because it’s a natural preservative. Except…

When researchers studied GSE and its antimicrobial properties they found that most of their samples were contaminated with benzethonium chloride, a synthetic preservative, and some were contaminated with other preservatives, some of which really weren’t very safe at all. And here’s the kicker, the samples that weren’t contaminated had no antimicrobial properties.

In other words, either your ‘natural’ grapefruit seed extract is a preservative because it’s contaminated with synthetic preservatives, or it’s not a preservative at all.

If you're worried, just use cotton wool pads and water.

You can always use cotton wool pads and water.

If you’re worried that baby wipes may be irritating your baby’s skin – I’m not claiming this never happens – then the best, and cheapest, thing to do would be to simply follow the NHS guidelines and use cotton wool and water. It’s actually easier and less messy than you might imagine – packets of flat, cosmetic cotton wool pads are readily available (and pretty cheap). Simply dip one in some clean water, wipe and throw it away. It’s really no more difficult or messy than wipes.

But if you’re choosing a particular brand of wipes on the basis that they’re “chemical-free”, despite the fact that other types have never actually caused irritation, you can stop. Really. Buy the cheap ones. Or the nicest-smelling ones, or the ones that come out of the packet most easily. Because NONE of them are chemical-free, and it’s really not a problem.


Follow The Chronical Flask on Facebook at fb.com/chronicleflask and Twitter as @chronicleflask for regular updates.

 

 

 

Should you be scared of your shampoo?

I was doing some grocery shopping online recently (I have small children, I’ve started to view traditional supermarket shopping in the same way as beating my carpets with a stick and washing clothes in a stream) when I came across some reviews for a particular brand of shampoo.

Most of the reviews were positive, but some were not. In particular, there were a few one star ones complaining about ingredients called methylchloroisothiazolinone and methylisothiazolinone.

273px-Methylchloroisothiazolinone_structure.svg

methylchloroisothiazolinone

What, you may be wondering, are these monstrosities? Surely with names that long they must be huge great big molecules? Actually no, they’re quite small. Methylchloroisothiazolinone (shown in the graphic) has a mere four carbon atoms and an interesting assortment of other elements. They’re part of a group of compounds called isothiazolinones, which are heterocyclic molecules that include a five-membered ring which contains nitrogen, sulfur and a C=O group.

Not surprisingly considering the unwieldy name, methylchloroisothiazolinone is often shortened to MCI. Likewise, the chemically-similar methylisothiazolinone (imagine the molecule above without the -Cl bit) goes by the moniker MI, or sometimes MIT.

MCl and MI are common preservatives in cosmetic products

MCl and MI are common preservatives in cosmetic products.

Why are these things in shampoo? Well, they are very effective preservatives. They’re antibacterial and antifungal, and work against both gram-positive and gram-negative bacteria, as well as yeast and fungi. This is a good thing, because some of these microbes are pretty nasty. The bacteria, for example, include such lovelies as Nocardia (associated with a particular type of respiratory disease), Staphylococcus (associated with various infections) and Listeria (most famous for causing gastrointestinal distress). It may be a small risk, but showers are warm, moist environments – basically the perfect breeding ground for these sorts of things. If these microbes start growing in your shampoo, shower gel and so on, they would then end up on your hair and skin, possibly be inhaled, and might even make their way into your bloodstream if you had a small cut somewhere.

Yuck.

So, that’s why these chemicals are there. That all sounds good, right? Why are people complaining?

The dose makes the poison is an important principle in toxicology (image credit: Lindsay Labahn, click for link)

The dose makes the poison is an important principle in toxicology (image credit: Lindsay Labahn, click for link)

Well, because they also have their hazards. Now, before I go any further, we should remember a very important principle of toxicology, which is that “the dose makes the poison“. Everything, I really mean EVERYTHING, is dangerous if you’re exposed to too much of it. Oxygen is quite crucial if you want to carry on living, for example, but breathe in too much of it for too long and you’re at risk of developing visual disturbances, tinnitus, nausea and muscle spasms. Too much could even be lethal. Similarly, a pinch of salt is quite nice on chips, but try and drink say, seawater, and you’ll soon regret it. Even plain water can be dangerous if you consume too much in too short a time, particularly if you’re also exercising hard.

Many chemicals that are used industrially have scary lists of associated hazards, but it’s important to remember that these warnings are usually aimed at people who use said chemical in an industrial setting. In other words, they might be handling kilograms or even tonnes of the stuff, all day every day, as opposed to the teeny tiny quantity you’re likely to meet a few times a week.

I could pick literally any ingredient in that shampoo bottle and proclaim that it’s dangerous. This would be perfectly true, but also meaningless. A more pertinent question is: is it dangerous in the quantity that you usually use?

Are methylchloroisothiazolinone and methylisothiazolinone in shampoo dangerous? There’s no evidence that they bioaccumulate (build up in the body) or that they’re linked to any kind of cancer (phew). In 2002, there was an in vitro (i.e. outside of living organisms) study of the neurotoxicity of MI which showed that mature neurons in tissue culture could be killed by 4-12 ppm solutions of the chemical. But these experiments were performed on rat brain cells in culture. Lots of things will damage cells in a petri dish: it doesn’t mean that we necessarily have to worry about them in every day life. A shampoo solution pouring straight into your brain might well be harmful, but I suggest that if that’s happening in the shower you have bigger problems. Namely, major head trauma.

However, in high concentrations, MI and MCl are definitely skin and membrane irritants, which can cause chemical burns. They’re known chemical ‘sensitisers‘. This means that exposure to them, even at fairly low levels, might cause an allergic reaction.

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A patient who presented to a medical centre following a severe reaction to methylisothiazolinone in a wipe (SA Government – click image for source).

This is where we get into difficult territory, because exactly how a particular individual is going to respond to something like this can be hard to predict. For example, I’ve never had a nasty reaction to methylchloroisothiazolinone. Give me an aspirin, on the other hand, and I’m likely to be in trouble. Allergies are specific to individuals. But there is no doubt that some people do have nasty reactions to MCI and MI; some sources have suggested it might be as many as 15% of the population (and that this number might, worryingly, have increased in recent years).

These chemicals are, or at least have been, also used as preservatives in other products such as sunscreens, moisturisers and wipes (baby wipes, facial wipes and moist toilet tissue, for example), which is a particular concern because you don’t wash off the the residue from these products – that generally being the point of using them – so it lingers on the skin.

A 2014 report from the International Journal of Toxicology concluded that although MI and MCI are sensitisers at concentrations of 50 ppm and above, they weren’t at concentrations of 15 ppm (and below). And therefore they, “may be safely used in ‘rinse-off’ products at a concentration not to exceed 15 ppm and in ‘leave-on’ cosmetic products at a concentration not to exceed 7.5 ppm”.

However, also in 2014, the European Commission Scientific Committee on Consumer Safety argued that: “For leave-on cosmetic products (including ‘wet wipes’), no safe concentrations of MI for induction of contact allergy or elicitation have been adequately demonstrated.”

People have been particularly worried about children, especially with respect to baby wipes. This is not unreasonable, since not only is the contact dermatitis that can occur painful and unpleasant, but once sensitisation has occurred it can’t be reversed: anyone affected will have to read labels extremely carefully for ever after. As a result, consumer groups have campaigned to have MI and MCI removed from any product that’s left on the skin over the last few years.

I happen to have three different brands of baby wipes in my house at the moment (small children you see), and a quick glance at the ingredients tells me that MI and MCI aren’t in any of them, and nor are they ingredients in the packet of flushable moist toilet tissue in the bathroom. This is hardly a comprehensive survey of course, but it suggests that these substances might be falling out of favour. Big companies aren’t really out to get us: pictures of people with nasty skin lesions after using their products doesn’t do them any favours.

Some consumers have complained about the use of MI and MCl in products.

Some consumers have complained about the inclusion of MI and MCl in products.

Do you really need to worry? Were these consumers right to highlight the fact that the shampoo contains MI and MCI in their reviews? Well, if you know you have sensitive skin then these substances probably are best avoided. But is shampoo likely to cause sensitisation if you’re fortunate enough to be blessed with the sort of skin that generally doesn’t erupt into a rash if the wind so much as changes? No one can say for certain, but it seems unlikely because you wash it off: these substances are only in contact with your skin for a few seconds.

So, whilst it doesn’t hurt to be aware of such things, there’s probably no need to panic and throw out all your shampoo just in case. On the other hand, if you’ve been wondering why your skin seems to be permanently irritated, it might be worth checking a few ingredients labels.

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Is oxygen really that good for you?

dove oxygen shampoo officialI don’t find time for huge amounts of television these days, and certainly not adverts. But I recently caught an advert for Dove Oxygen Shampoo out of the corner of my eye, and it brought me up short. Of course, beauty products are full of nonsense generally. Think, for example, of L’Oreal’s famous ingredient, ‘Boswelox’. (A word which, thanks to the wonderful Karl Pilkington, has since acquired a whole new meaning.) A little while ago I wrote a post about a toothpaste that was claiming to contain ‘liquid calcium’ (if it were true, cleaning your teeth would be much more exciting, trust me). It’s just par for the course. Really, is there any point wasting valuable energy continuing to be annoyed by these things?

Well yes, actually. Because this kind of silly hogwash just reinforces the ridiculous ‘science is so terribly hard, oooh aren’t all the complicated words impressive?’ attitude that is so frustratingly prevalent in the world today.

Besides which, picking apart this kind of thing is practically the reason for the existence of this blog. So here goes.

Firstly, a few snippets from Dove’s website:

“Oxygen & Moisture shampoo, conditioner and finishing products are pumped with Oxyfusion Technology, a new generation of moisture. This system moisturises fine, flat hair, giving you hair volume.”

And clicking through a bit further:

“[the shampoo] provides conditioning ingredients fused with oxygen as it instantly dissolves on your hair and breathes life into it.”

Hm.

Let’s start with that last sentence. Firstly: it dissolves on your hair? What does that mean? I’m just going to mention here that the meaning of the word dissolve is taught in year 7 (first year, in old money) science in all secondary schools in this country, and has been for many, many years. So everyone should know it, even the employees of the media company that came up with this tosh. (If you don’t, and you’ve ever muttered anything whatsoever about slipping standards and/or grade inflation, shame on you.)

‘Dissolve’ usually refers to solids. Salt dissolves in water. Sugar dissolves in tea (yes all right, also mostly water). It means that the solid becomes incorporated into the liquid, forming a solution. I haven’t checked, but I’m assuming Dove’s shampoo is not solid, as that would make it rather difficult to get out of the bottle.

Ok, oils and fats dissolve in certain solvents (not water mind you), and they could feasibly be liquid and yet the word still applies. True enough. It’s possible that the original text was ‘dissolves the grease on your hair’ (more or less accurate enough), and some marketing guy said, ‘I like really love it, I really reaaaahhhly do, but can we just lose two words from the middle?’

And yes, I think it’s safe to assume their shampoo mixes with water, because that is quite an important feature of shampoo, but they haven’t said ‘dissolves in the water’, they’ve said ‘dissolves on the hair’, which does sort of give the impression that it’s your hair that’s somehow dissolving the shampoo. Which is just weird.

But misuse of the world dissolve is only a minor irritation. No, my bigger problem is ‘ingredients fused with oxygen’. What the Dove does that mean?

For years and years we’ve been told that oxidants are bad. Or at least, that antioxidants are good (although this hasn’t really been backed up by scientific studies).

Is it difficult to work out that oxygen is an oxidant? It’s the granddaddy of oxidants. It’s the oxidant that all the other oxidants were named after. Oxy/oxi – see?

Chemists have two definitions of oxidation, but they’re broadly equivalent. Oxidation can be thought of as gaining oxygen, or it can be thought of as loss of electrons. Electrons are the negatively-charged particles that surround atoms. I mention them because the phrase ‘free radicals’ often turns up in the same breath as ‘antioxidants’. Free radicals are atoms or molecules which have an unpaired electron. Electrons like to be paired up. They REALLY like to be paired up. When they’re not, they’ll do pretty much anything they can to get paired up. Unpaired electrons are, if you like, the desperate guy at the nightclub at the end of the night. This makes them incredibly reactive, which means they can cause cell damage.

Worse, this happens in a chain reaction – meaning that a single free radical can do an awful lot of harm. So where to antioxidants come in? Well, antioxidants react with free radicals and essentially stop them in their tracks.

oxygen cylinder

Don’t suck on this.

Jolly good. But you see where I’m going here? Oxygen is the complete opposite of this. Yes, we breathe oxygen. It’s quite important stuff. Certainly, if you run out of it you’re in trouble. But it’s far from harmless. The air we breathe is only about twenty-one percent oxygen. Too much oxygen is flat-out dangerous. Breathe air with something like 50% oxygen for any length of time and you risk damaging your lungs, eyes and central nervous system. Really. Hospitals control oxygen use very carefully, and scuba divers who use it have to undergo rigorous training. The fad for oxygen bars has caused real concern in some quarters.

What does ‘ingredients fused with oxygen’ mean? Does it mean Dove have somehow dissolved oxygen in their shampoo? I’m certain that it doesn’t, because this wouldn’t be stable, and it would likely cause your shampoo to ‘go off’ in some way very quickly. Does it mean that their shampoo contains an ingredient that releases oxygen somehow? Hydrogen peroxide famously does this, when it breaks down into oxygen and water. Of course hydrogen peroxide is used to bleach hair, so… probably not (and anyway, again, not stable).

I looked up the ingredients in Dove Oxygen Moisture shampoo (and I’ve reproduced them below). To be honest, looking at the list I’m drawing a blank. My suspicion is that they’re using ‘oxygen’ simply because it’s the latest trendy thing. Oxygen is common enough – water contains one atom of oxygen in every molecule for starters, so they’re safe with the idea that the shampoo contains oxygen in some form – just not elemental oxygen.

But, ok, if I had to pick something… there is an interesting ingredient called ‘guar hydroxypropyltrimonium chloride‘ in there. If that is the one that inspired them, I can see why they went with Oxyfusion Technology – guar hydroxypropyltrimonium chloride hardly trips off the tongue.

Sucrose

Table sugar (sucrose) – perhaps we should wash our hair with this?

620px-Guaran.svg

Guar gum – check your salad dressing. Another conditioning alternative perhaps?

I’ve picked that one out of the list partly because it has ‘hydroxy’ in its name. Now in reality, that just means it contains an -OH group or several. This isn’t anything particularly special, table sugar has eight of ’em. Guar hydroxypropyltrimonium chloride comes from guar gum, which in turn is made from guar beans. Guar gum is a food additive that’s used to thicken foods, and it turns up all over the place (check your salad dressing or ice cream).

Guar hydroxypropyltrimonium chloride has been shown to have conditioning properties, which explains its inclusion in shampoo (this is my other reason for picking it out). It probably does leave your hair feeling nice and soft. And it does have several -OH groups, so it arguably sort of works with the ‘conditioning ingredients fused with oxygen’ claim. In the sense that it has oxygen atoms chemically bonded to it. As does, you know, water.

There’s no way that it releases oxygen though. Now in fairness to Dove, that claim isn’t actually made explicitly anywhere, although the lovely bubbly imagery does its damnedest to imply it.

Bad-Hair-Day

Bad hair day?

And here’s the thing: even if you could, would you want to routinely use a product that releases oxygen directly onto your skin or hair? Given that oxygen is an oxidising agent, and is likely to cause cell damage in high concentrations? Just bear in mind what happens to hair that’s exposed to too much hydrogen peroxide.

And don’t even get me started on the dozens and dozens of moisturisers that claim to do the same. Really? Straight into your skin? There are even some products that claim to do both at once, which frankly is jolly clever. In the Doctor Who sense of clever. I.e. fictional.

But what I want to know is this: after years of anti-oxidant this, and anti-oxidant that, how have we managed to go in exactly the opposite direction without consumers saying ‘er, hang on a minute, surely this has to be a load of old boswelox?’

Ingredients in Dove Oxygen & Moisture Shampoo:
Aqua, Sodium Laureth Sulfate, Sodium Chloride, Cocamidopropyl Betaine, Glycerin, Citric Acid, Dimethiconol, Disodium EDTA, Guar Hydroxypropyltrimonium Chloride, Laureth-23, Parfum, PPG-12, TEA-Dodecylbenzenesulfonate, TES-Sulfate, DMDM Hydantoin, Sodium Benzoate, Amyl Cinnamal, Benzyl Alcohol, Benzyl Salicylate, Butylphenyl Methylpropional, Hexyl Cinnamal, Limonene, Linalool, CI 17200, CI 42090.

Liquid calcium? Why words really matter in chemistry

dl-265_1zI happened to see an advert for Arm & Hammer toothpaste on TV a couple of days ago, in which they cheerfully proclaimed that it contained “liquid calcium”.

navigator_highlighted_periodic_table

Calcium, on the left. With the metals.

This brought me up short.  First thing: calcium is a metal.  Now, as a famous British movie star might say (or perhaps might not say), “not many people know that”.  Ask a roomful of people if calcium is a metal and most of them will tell you it’s not.   I’ve even heard students who know what the periodic table is and what the position of elements within it means, and who can see calcium right there on the left hand side, express their doubts.  Everyone associates calcium with bones and teeth, possibly rocks at a push.  No one (other than chemists of course) hears ‘calcium’ and thinks of a silvery-grey metal.

But that is indeed what it is.  It is a metal, and although its melting point isn’t huge in the grand scheme of metals, it’s still a fairly substantial 842 oC.  The temperature in your bathroom is probably in the region of 20 oC.  In fact your kitchen oven probably only goes up to about 240 oC, so the melting point of calcium is some 600 oC hotter than the hottest setting on your oven.

ca_2_2

Calcium and water: what you can’t see is how hot this sucker is going to get.

Temperature problems aside, pure calcium is also highly reactive.  Drop some in water and you’ll see a lot of violent bubbling followed by the solution turning white as a corrosive calcium hydroxide solution forms.  The bubbling is due to flammable, potentially explosive, hydrogen gas.  Oh, and it will get really, really hot too – this is what chemists call an exothermic reaction.  I for one will confess to once (many, many years ago, of course) dropping a red-hot boiling tube into which I’d popped just a little too much calcium metal.  After it had also bubbled up and covered my hand with the aforementioned calcium hydroxide.  Ooopsie.  (Fear not, my hand survived unscathed, after the application of copious amounts of cold water – the go-to cure for most chemical exposures).

So, at the risk of stating the obvious, there’s no liquid calcium in Arm & Hammer toothpaste.  And a jolly good thing too.

What is there?  At this point I should probably point out that Arm & Hammer are quite careful, in their literature and on their packaging, to always put a little ™ by “Liquid Calcium”.  A quick glance at their website clarifies that they’re talking something called “Liquid Calcium ™ Technology” which refers to an ingredient that contains “up to 8 times more calcium and phosphate ions than the amount found in saliva so it is able to replenish ion content in your mouth and subsequently re-mineralise and protect your teeth more efficiently.”

Ah, now we get to the truth of the matter.  It’s not liquid calcium, but calcium ions in solution.

Does this matter?  Am I being unnecessarily pedantic?  Liquid/solution, calcium metal/calcium ions, what’s the difference?

H2O2

When an extra O really matters.

Well, the thing is, chemists are pedantic.  See, in chemistry, it genuinely could be a matter of life and death.  Ethanol, for example, is ‘drinking’ alcohol.  It’s the stuff in beer, and wine, and strawberry daiquiris.  It may not be exactly healthy, but most adults can consume some fairly safely.  Ethanal, on the other hand, is a toxic and probably carcinogenic substance that’s mainly used industrially as a starting point to make other chemicals.

To pick another example, chlorine is a highly toxic gas that’s been used in chemical warfare; chloride ions are found in salt and are consumed perfectly safely every day.  The difference between ions (atoms or molecules which have become charged due to the gain, or loss, of electrons) and atoms is really quite critical in chemistry, and in life in general.

potassium and water

Potassium reacting with water – pretty!

‘Everybody’ knows that bananas contain lots of potassium.  But potassium is another highly-reactive metal.  In fact it’s even more reactive than calcium.  Potassium explodes with a rather beautiful lilac flame in contact with water.  It’s pretty to watch, but you wouldn’t want it in your mouth.  Actually bananas contain potassium ions (and just to really mess with everything you thought you knew, not even that much compared to lots of other foods).

Back to the dubious labelling again, It’s interesting that Arm & Hammer have chosen to say “fluoride” – which specifically, and correctly, refers to fluoride ions – and not “liquid fluorine”.  I mean surely, in the spirit of consistency, it should be liquid fluorine and liquid calcium (argh!), or fluoride ions and calcium ions.

The word liquid has a specific meaning in chemistry.  It means a pure element or compound in its molten state.  Pure water at room temperature is a liquid.  So is ethanol, and mercury, and bromine (interestingly these last two are the only chemical elements which are liquids at room temperature).  Ethanol dissolved in water, as it is in strawberry daiquiris (more or less), isn’t a liquid.  It’s a solution.  This matters.  Liquid ethanol is pure ethanol.  Drink that and you’re looking serious alcohol poisoning in the face, and it’s about to wallop you for looking at it funny.

frustration_350px

An Arm & Hammer chemist?

Saying, or even implying, that calcium ions in solution is ‘liquid calcium’ is like saying that seawater is liquid sodium (sodium is another highly reactive metal – orange flame this time).  It’s just nonsense.  Ok, it’s probably not going to cause anyone any actual harm, but that’s not the point.  It’s completely factually inaccurate.  I am absolutely certain that the chemists working for Arm & Hammer wanted to tear their hair out when the advertising company came up with this name for the formulation they’d spent (probably) years slaving over.  And I expect they were essentially told to shut up about it, the vast majority of our customers won’t know the difference.

And sadly this may be true.  But it shouldn’t be.  Would Arm & Hammer care if their boxes were labelled ‘tothpast’ instead of toothpaste?  I bet they’d be bothered if the boxes were priced at £250 instead of £2.50.  Why fuss over spelling and numbers but be careless over scientific literacy?  Either precision matters or it doesn’t.

Perhaps it’s time scientists starting making as much noise about this kind of thing as people who complain about stray apostrophes or the misuse of the word disinterest.  You never know, it might help levels of scientific understanding.

Mind you, perhaps the author of a blog called The Chronicle Flask shouldn’t throw stones…

—-

After I wrote this post I tweeted something referring to “liquid phosphorous”.  It was pointed out to me, quite rightly, that I meant “liquid phosphorus”.  Phosphorus is the noun – the name of the chemical element – and phosphorous is an adjective.  As in, “phosphorous fertiliser”.  I confess I was a bit hazy on that one until made to check, which is ironic really. Consider me sent to the back of the class 😉