It has taken until nearly August for summer and the sun to make its fleeting appearance here in the UK, perhaps there is some truth behind King George II’s remark that the British summer consists of three fine days and a thunderstorm. With sun though comes one of my pet hates - sun protection lotion. I’m acutely aware of the protection it offers and why it needs to be applied, but repeatedly applying it is tiresome and it seems to stain or mark anything it comes in to contact with. That got me thinking, what actually is in sunscreen that makes it so effective at blocking out harmful rays, but also just as effective at staining clothes, paintwork, etc. and not always as waterproof as suggested?
What Are Sunscreen Ingredients?
I didn’t actually know, so did some research and found that in fact there are a wide range of ingredients that can be used in sunscreen, a list of which can be found in this Wikipedia link. As you will see, not only can a wide range of chemicals be used, but the percentage of the individual compounds is strictly regulated. So that begged another question, how do I find out which of these are actually in my sunscreen, are they within the recommended limits and what technologies are involved to identify them?
This is when I turned to the Thermo Scientific™ AppsLab™ Library of Analytical Applications. Within AppsLab you can search for methods based on a number of different parameters such as compound, matrix, instrument, etc. It will then show you the most relevant applications from the library. When I performed my search on sunscreen, I found a method based on HPLC using a mixed mode column (Thermo Scientific™ Acclaim™ Mixed-Mode WAX-1 HPLC column). In this method it was shown that the active ingredients in the lotion were Octyl salicylate and Octly methoxycinnamate and that both compounds were present in concentrations below the maximum permitted amounts.
This shows that if I really want to know what is in my sunscreen and also if these compounds are present below recommended levels, then liquid chromatography methods are available to be able to determine this – I just need to ask one of our application chemists very nicely to do the analysis for me.
How to Find a Method, Not Just for Sunscreen
If you are searching for a method, whether for sunscreen or not, then the AppsLab Library of Analytical Applications is a great place to start with hundreds of searchable methods for LC, IC, GC, GC-MS and LC-MS. When you have found your method you can view the method and related documents, create a parts list of even download eWorkflows, which can be directly executed in your Thermo Scientific™ Dionex™ Chromeleon™ Chromatography Data System (CDS). If a suitable method does not exist then you can request it. I think I will request a method for my current sunscreen, just to check before my holiday!