The New Globally Harmonised System of Classification and Labelling of Chemicals Pictograms Explained

Like many others around the world, my laboratory is finalising our compliance with the new globally harmonised system of classifying and labelling chemicals (GHS). Part of this process has involved relabelling many of our chemicals with the new GHS hazard pictograms. Some of these pictograms are different from those we have used in the past, and the hazard is not always obvious from the picture alone so it is necessary to commit to memory what all of the pictograms represent. Hence I have provided this handy guide to interpreting the new set of pictograms.



I hope this guide has been helpful to you.

When advertisers try to chemistry

On a recent trip to one of the lands, I noticed this billboard advertising a school.

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Immediately I LOVED IT because chemistry! But soon after I didn’t love it anymore. The peroxide decomposition equation is wrong, with the subscript 2 following the oxygen instead of the hydrogen in what should be the formula for water. I’d expect a little better from an educational institution.

So then I go inside to Woolies, where they are running some kind of school fundraiser bizzo advertised thusly.


The ad has an adorable kid doing chemistry, so I LOVED IT. He’s unneccessarily wearing a lab coat but that’s OK because where else would he put his carefully askew coloured pens? His safety goggles are on his head but that’s OK – if he whacks himself in the eye with his Molymod he’ll probably live.

And then soon after I didn’t love it anymore. The molymod he’s holding was not a molecule immediately identifiable to me (I am an analytical chemist after all) so like any normal person would do, I opened up ChemDraw and tried to recreate the structure chemkid is holding. There is definitely an aromatic ring in the bottom half… a slightly odd ammonium group near the top… a carbon-nitrogen double bond on the left? a triply-bonded oxygen on the right? IDK but the kid’s hand and the angle of the shot and my general suckiness at this sort of thing made it hard for me to really tell what was going on there other a big ole hot mess.



I got confused. so like any normal person would do, I got out my own molymod kit and tried to make the molecule. I came unstuck again, mostly because I ran out of carbons and party because it appears to be a made up molecule.



So, 2 chemistry fails in one shopping trip. Plus Woolies was sold out of my favourite bread. For the record, advertising people, there’s a bunch of chemists on the internet who will help you with this kind of thing for free. For the love of science, all you have to do is not just make shit up.

Q. Vegemite Chocolate, How Does it Smell?

A. It can’t, it doesn’t have a nose.


When I die and the internet writes my epitaph, it will say “here lies Renée, she did some chemistry on the smell of Vegemite”.

As such, I felt that when Cadbury released Vegemite Dairy Milk chocolate to the market, it was my solemn duty to once again do some chemistry on the smell of Vegemite. I decided to repeat the aroma analysis experiment on the Vegemite filling from the chocolate and compare with the results from the original Vegemite analysis. The product description states that the filling is caramel mixed with Vegemite so I thought it would be interesting to see if the aroma compounds that were prominent in the Vegemite analysis are present in the chocolate filling, and if any new compounds might be identified from the caramel component.


I used the same extraction and analysis procedure as the previous experiment, so I could directly compare the chromatograms. The results of the two analyses are below, with the original Vegemite in red below and the Vegemite chocolate filling in blue above.




It’s clear to see that there are some key compounds present in both the Vegemite and Vegemite chocolate samples. The three major peaks are common to both samples. These are the ethyl esters of octanoic and decanoic acids, and trans ethyl-4-decenoate. Many of the other smaller peaks are also present in both Vegemites. However, not unexpectedly, there are a couple of compounds present in the Vegemite chocolate filling which are not found in the original Vegemite sample. Notably, tetramethyl pyrazine with the odour descriptors nutty, musty, vanilla, cocoa and maltol which is sweet, caramellic, cotton candy, fruity, bready, and phenyl acetaldehyde with honey, floral rose, chocolate aromas.

Some of the interesting peaks from the original Vegemite analysis (sulfurol, niacinamide, caryophyllene etc.) were absent in the chocolate sample, although I am leaning towards attributing this to dilution effects from mixing with the caramel and an unoptimised analytical method rather than them being somehow ‘removed’ from the product.

To conclude, although I am a fan of both Vegemite and chocolate, I had no qualms in sacrificing a few squares from the block in the name of science. Would not buy again, 1 star.



Chemicals are OK after all

The Royal Society of Chemistry has just released the results of their survey into the public attitudes towards chemistry, which you should totally go and check out here. I haven’t had time to read the full report yet, but there is a nifty infographic summarising the findings and you can watch the presentation of the findings on youtube as well. Thanks to Mark Lorch looping me into this by tagging me on Twitter, and massive props to the RSC for commissioning the study.

The most interesting thing to me was the “public attitudes to chemicals section”. Apart from a few choice certified rolled gold douchecanoes like the Food Babe, turns out most people are all over ALL OF OUR FAVOURITE PITHY PHRASES. Including “everything is made of chemicals”, “the dose makes the poison” and “many chemicals are naturally occurring”. So turns out all this whining we’ve been doing about chemophobia and people generally being science-hating idiots who hate science is a bit of a circle jerk.

Holy confirmation bias, Batman – that’s totally what I have been thinking lately anyway!

I realised I was on the path to mellowing (pretty sure it’s mellowing and not apathy) just this weekend. We went down to our favourite local restaurant for dinner, only to find that one of the night’s specials was a Gippsland steak with “no chemicals”. I pointed this out to my dinner companions and the conversation went something like this:

Me: nobody order the chemical free steak, that’s quite expensive for a plate of nothing
Dinner companion 1: babe, let it go
DC2: oh, but everything is made of chemicals!
Me: why did they write that? What do you think they actually MEAN?
DC3: I think they are trying to say there there is nothing artificial, nothing added to the meat. It could even mean organic?
Me: yeah orroight then

And I didn’t even pick a fight with the waitstaff or owner about it and I didn’t yell and we’re going to keep going back there because the food is ace and there are table lamps hanging from the walls and ceiling and it’s quite nearby our house.

Maybe I’m saying I now think it’s OK to use the word “chemical” in this way? Sometimes? People are savvy enough to comprehend that there are different meanings for this word in different contexts. The chemicals missing from a steak with no chemicals are different to the chemicals that I order from Sigma-Aldrich and are different from the chemicals you put in your swimming pool. It’s OK. Most of the time we can figure out what is meant. And as someone famous once said “the key to communication is the message received”

So what are we all going to blog about now chemists? On second thoughts, I can’t rule out the possibility that I will get my angries on about this again in the not too distant future.

Books in Scientia – The Unfinished Files

This is a post about a few of the books I started reading with the intention to review here, but I never finished.

Titles and authors

Oxygen: The Molecule that Made the World by Nick Lane
Poisoned Planet by Julian Cribb
The Joy of Chemistry by Cathy Cobb and Monty Fetterolf

How far did I get?

OtMtMtW: half way-ish, maybe just under

PP: about three-quarters of the way

TJoC: not quite halfway

Why didn’t I finish it?

OtMtMtW: It just didn’t hold my interest. The narrative component of the book was weak, and it had a very textbook-y feel about it a lot of the time.

PP:  There are too many false analogies, giant leaps of faith, baseless assertions and misinformation to make this book worthwhile. I wrote 2 pages of notes about all of the wrongness. I also managed to rack up a $180 library fine thanks to this book (long story) but that in no way clouded my judgement.

TJoC: This book was pitched at a level too far below my interest and expertise.

Any redeeming qualities?

OtMtMtW: It’s clearly taken a lot of research to write and the information appeared to be sound. It would be a good reference material or starting point from which to really deep-dive into any of the topics covered.

PP: The premise is interesting and seems like something worth writing a book on – why aren’t we doing a whole lot about looking into the effects of industrial chemicals and by-products?

TJoC: I think it would be great for someone with an interest in chemistry who had never done it above a high school level. There are a lot of decent experiments in there that can be done with household items. It was just too basic for someone with a chemistry degree and 10 years of professional chemistry experience.

Chemicals What Even Are They

Chemophobia is a constant cause for consternation amongst chemists (alliteration FTW), and a regularly discussed topic on this blog. I often think and write about irrational fear of chemicals and the incorrect or misinformed usage of chemistry in the media, pop culture and modern life. Recently, I had an epiphany and have probably solved all of these problems for ever. OK maybe not but I thought it was worth blogging about.

In a recent visit to a materials science lab, I came across this sign on the door:

2015-02-18 12.56.08

At the time I made a totes hilare crack about the lab being a vacuum chamber, because as we all know EVERTYHING IS CHEMICALS RIGHT therefore game over idiots the smug chemists win again. But I continued to think about it for a while because the context of the sign within a professional setting that I know to be not completely incompetent with respect to OHS was somewhat puzzling to me. I think in these situations, the place where I always come unstuck  is what on earth do people actually mean when they say “chemicals”? It eventually dawned on me that that in this case, the word “chemicals” should be replaced with the phrase “hazardous chemicals” and everything would be 110 percent super and OK and making sense and perfectly fine and reasonable.

With the introduction of the Globally Harmonised System of Classification and Labelling of Chemicals (don’t even get me started on the first sentence on that link, just don’t even), the phrase “hazardous chemicals” is clearly defined under the Australian Work Health and Safety (WHS) Regulations using the GHS.

So, given that I totally solved this workplace chemical mystery, I wondered if I could apply the same logic to other bogus chemical claims out there. Maybe every time someone other than a chemist uses the word “chemical”, they actually mean “hazardous chemical as defined by the globally harmonised system of classification and labelling of chemicals” and of course they wanted to say or write this but it was just a teensy bit too long. My first port of call for chemistry idiocy is of course the Food Babe, who particularly hates the antioxidant BHT, the yogi’s favourite urea derivative azidocarbonamide and 1958 heterocycle of the year 4-methyl imidazole. When I search for these three compounds in ChemAlert (an Australian chemical management and compliance program), the results are shocking (OK not actually that shocking).


Yes, these three HAZARDOUS CHEMICALS are permitted in food and perfectly safe at certain concentrations – the dose makes the poison after all. So I wondered, is it possible that every time someone is concerned about “chemicals”, they are actually referring to Hazardous Chemicals which, by definition, are something surely worth a little consideration? Answer: YES CHEMOPHOBIA PROBLEM SOLVED FOREVER.


One example in violation of my proposed solution is artificial sweeteners. For example aspartame, which is not a Hazardous Chemical but is something that people like Food Babe, Mercola, Mike Adams et al. flip out about. Here I think the word chemical is used in the chemical=synthetic sense. Eh, can’t win them all…

Books in Scientia – The Science of Ice Cream

Title and author

The Science of Ice Cream by Chris Clarke

What’s it about?

Ice cream. In particular, the scientific aspects of the aforementioned frozen confection. A good title’s a descriptive title eh.

What are the good bits?

I learned a lot of new things about ice cream. The hands-down best thing I learned about was Dondurma, which is a Turkish ice cream that is chewy! The first chapter is an interesting history of modern ice cream. The detail included about the characterisation and properties of ice cream was both extensive and fascinating.

What are the not-so-good bits?

This book is not intended to assist the home cook and has little to offer in this area. It is very much focused on industrial scale ice cream production. There are a few try-this-at-home experiments in the back but they seemed at bit ‘meh’ to me (although I am a somewhat experienced home ice cream cook. In fact, I’ve renamed the ice cream I make at home to “nice cream” because it’s pretty effing good OK.

Also, not the fault of the book or author, but my chemophobia alarm sounded loudly when in the chapter discussing ingredients, sodium carboxymethyl cellulose was described as being longer routinely included in ice cream because of “it’s perception as a chemical”. This is after a long list of other chemical stabilisers including carageenans, pectin and xanthan. LARGE SIGH TO YOU ICE CREAM MANUFACTURERS.

What does it say on p89 line 11?

Tacos are a type of sandwich product consisting of a semi-circular shaped wafer that contains icecream and sauce (Figure 5.4b)


Who should read it?

People who would like to find out more about how ice cream is manufactured, and the macro and micro physical properties of different iced products. Those with a strong interest in rheology, microscopy and composite materials may also find much of the content quite satisfying.

How good is it?

It’s pretty good for a book with a decent amount of physics in it. I do like ice cream.

stars ice cream





3 round bottom flasks out of 5


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