Letter 31079

How to do Artificial Sweat Test

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Hello, we manufacture ECG (electrocardiograph) electrodes. Actualy we have 3 new prototypes with Ag-Cl surface and we want to compare which one is the best - highest resistance to corrosion. Does anybody help how to simulate a human sweat or how to prepeare an corrosive enviroment for comparing? I am not very good in chemistry.

Thanks,

Eduard Sajmir
medical - Prague, Wertyui, Czech Rep

The American Association of Textile Colorists and Chemists, AATCC, has published Method 15 which includes a section on Preparation of Reagent to make 1 litre of artificial sweat. Most of the ingredients are readily available through scientific supply houses. You might also do a word search through ASTM International test methods at astm.org.

In addition to checking your parts for corrosion resistance in the presence of human sweat, you should also take into account the conditions encountered in transport and storage. Keep in mind that most corrosion takes place during transitions from moist/saturated to dry to moist, etc., which means that testing an item by keeping it constantly wet is not as good as alternating between wet and dry.

Harold D. Hilton
Atlas Material Testing Technology - Chicago, IL, USA

You would have thought that there is an universally standard "artificial sweat", but according to the Internet, no such luck! It looks like there are different mixtures for different countries. The one used by the EU (especially for nickel release work) is defined by EN 1811 [link is to spec at TechStreet] and comprises 0.5% NaCl, 0.1% urea, 0.1% lactic acid and the pH adjusted to 6.6 with NH4OH. However, the ISO standard ISO 3160-2 [link is to spec at TechStreet] comprises 20g/l NaCl, 17.5g/l NH4Cl, 5g/l acetic acid and 15g/l d,l lactic acid with the pH adjusted to 4.7 by NaOH.

There is also another mixture comprising 7.5g/l NaCl, 1.2g/l KCl, 1g/l urea, 1ml/l lactic acid, pH = 4.57.

Another one used in Denmark comprises 4.5g/l NaCl, 0.3g/l KCl, 0.3g/l Na2SO4, 0.4g/l NH4Cl, 0.2g/l urea.

Other mixtures comprise 0.3% NaCl, 0.1% Na2SO4, 0.2% urea and 0.2% lactic acid, pH adjusted to 4.5.

Finally, two mixtures used by the Japanese are: 1) 19.9g/l NaCl, 1.7g/l urea, 1.7g/l lactic acid, 0.8g/l Na2S, and 0.2g/l NH4Cl Lastly, 2)17g NaCl, 1500ml CH3OH, 1g urea, 4g lactic acid made up to 1 litre by water. I suspect these different solutions are used for different tests and for different climactic conditions, so I think you will have to decide for yourself which is the most applicable for your needs.

Trevor Crichton R&D practical scientist - UK

We are looking for any articles of the chemical composition of artificial sweat. We are particular interested in the of a composition representative of hot weather climates.

Lucinda Quarles
New Mexico Technical - Sierra Vista, Arizona, USA

There is a error in the question I posted on Sept. ++++. The Inquiry should read: We are looking for any articles on the chemical composition of artificial sweat. We are particularly interested in a composition representative of hot climates conditions.

Lucinda Quarles
New Mexico Technical - Sierra Vista, Arizona, USA

Hey everyone, I'm a final year aerospace technology student at Coventry Uni and for my final project, I need to know the tests for nickel release. Now I think I've found that, but the crucial point I don't have is the compostion of the artificial sweat solution needed for the test. The product I'm testing is to be sold in the UK, so if anyone can help me out with the UK standard of sweat recipe, that would be great!

Thank you for your time!

Helen W
- Coventry, UK

Its probably too late now, but if you look at the submissions above you will see references to artificial sweat formulations especially for nickel release work (EN 1811). Never mind....perhaps there is a moral to this?

Trevor Crichton R&D practical scientist - UK

Ed. note: Indeed, the answer she sought was already on the page she was reading. Maybe the moral is feel free to eat hearty but if you demand spoon feeding you may go hungry.

Hi! I'm a sophmore in high school and I have to do a science fair project for my chemisty project. My topic is observing the amount of sweat absorbed by different backing to shin guards and the amount of time that it takes. I need a recipe to make artificial sweat for my project, since trying to use real sweat is too difficult to obtain and varies too much, I need to use artificial sweat. Can any help me out? I need it soon because the project is due in February and I need to get started.

Noosheen K.
student - Fairfax, VA, USA

I am a junior and am currently working on a chemistry project. I am experimenting with sweat and how it corrodes bass guitar strings. I need a chemical equation for artificial sweat that i will use to corrode the strings. I see that there many listed already, but which one is right or best for my situation? I also need a method for finding the composition of real sweat. Any help would be appreciated.

Jacob G
- Rothschild, WI, USA

Mr Trevor Crichton
I have a question.
I want to know what is the material in sweat that make it stinky.
please help me
I really need to know this
I am a chemical engineer student and I need this for my final project.
thank you

Hadi Shams
- Tehran, Iran

To The Iranian student

Sweat itself does not smell bad. Sweat comes from sweat glands and is mostly made of salt and water. Between the sweat glands are apokrina glands. These apokrina glands produce different fats, proteins and carbo hydrate- in other words, food for bacteria.

When the bacterias break down the substance, it starts to smell.

When deodorant is used the bacterias die and the smell goes away.

Stefan Kristo
- Göteborg, Sweden

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