Replicating sweat

[TodG]

This seems like a weird question.

Anyone have information for a formula that closely duplicates human sweat? I am looking to do some testing of anti-oxidizing agents for body cord connections and want to be able to simulate repeated exposure to sweat.

[Michael_Z]

from wikipedia:

"Sweat contains mainly water. It also contains minerals, as well as lactate and urea. Mineral composition will vary with the individual, the acclimatisation to heat, exercise and sweating, the particular stress source (exercise, sauna, etc.), the duration of sweating, and the composition of minerals in the body. An indication of the minerals content is: sodium 0.9 gram/liter, potassium 0.2 gram/liter, calcium 0.015 gram/liter, magnesium 0.0013 gram/liter[7]. Also many other trace elements are excreted in sweat, again an indication of their concentration is (although measurements can vary fifteenfold): zinc (0.4 mg/l), copper (0.3 - 0.8 mg/l), iron (1 mg/l), chromium (0.1 mg/l), nickel (0.05 mg/l), lead (0.05 mg/l). [8] [9]. Probably many other less abundant trace minerals will leave the body through sweating with correspondingly lower concentrations. In humans sweat is hypoosmotic relative to plasma.[10]"

[Redblade]

from wikipedia:

"Sweat contains mainly water. It also contains minerals, as well as lactate and urea. Mineral composition will vary with the individual, the acclimatisation to heat, exercise and sweating, the particular stress source (exercise, sauna, etc.), the duration of sweating, and the composition of minerals in the body. An indication of the minerals content is: sodium 0.9 gram/liter, potassium 0.2 gram/liter, calcium 0.015 gram/liter, magnesium 0.0013 gram/liter[7]. Also many other trace elements are excreted in sweat, again an indication of their concentration is (although measurements can vary fifteenfold): zinc (0.4 mg/l), copper (0.3 - 0.8 mg/l), iron (1 mg/l), chromium (0.1 mg/l), nickel (0.05 mg/l), lead (0.05 mg/l). [8] [9]. Probably many other less abundant trace minerals will leave the body through sweating with correspondingly lower concentrations. In humans sweat is hypoosmotic relative to plasma.[10]"

Well, if it's from an online wiki, it must be solid info.

Seriously, find an original, reliable, scientific source for citation, not a site that allows any yahoo and his dog to edit. Remember that horrible Superman movie where Richard Pryor's character inserted tar into the equation to create artificial kryptonite?

[TodG]

References cited by the wikipedia article look good.

http://www.ncbi.nlm.nih.gov/pubmed/18156662

Sweat was collected from a sweat-collection pouch attached to the upper back during exercise bouts 1, 3, and 5. Mineral elements were determined by using inductively coupled plasma-emission spectrography. RESULTS: At 27 degrees C, sweat sodium (863 [563] microg/mL; mean [SD]), potassium (222 [48] microg/mL), calcium (16 [7]) microg/mL), magnesium (1265 [566] ng/mL), and copper (80 [56] ng/mL) remained similar to baseline over 7 h of exercise-heat stress, whereas sweat zinc declined 42-45% after the initial hour of exercise-heat stress (Ex1 = 655 [362], Ex3 = 382 [168], Ex5 = 355 [288] microg/mL, P < 0.05). Similar outcomes were observed for sweat zinc at 35 degrees C when sweat rates were higher. Sweat rate had no effect on sweat trace-element composition. CONCLUSIONS: Sweat sodium, potassium, and calcium losses during multiple hours of sustained sweating can be predicted from initial sweat composition. Estimates of sweat zinc losses, however, will be overestimated if sweat zinc conservation is not accounted for in sweat zinc-loss estimates.

This gives me a baseline for a sweat recipe that is probably close enough for testing purposes.

Tod

[parrythis]

Anyone have information for a formula that closely duplicates human sweat?

Why replicate when the real thing is so readily available? I'll gladly wring out my plastron after a 4 hour practice and send you a sample that will more than meet your needs.

[keith]

A quick search got osmolarity ranges of 49-151 mmol/kg for men and 66-187 mmol/kg for women. You could simply make a saline to those osmolarities with table salt as a starting point.

Then there are things like Urea, lactic acid, Uric acid, ammonia that are going to make a difference.

Of course a simpler plan might be to just drop your test samples in Gatorade (I recall a claim that this was based on football players sweat).

[oiuyt]

Gatorade (I recall a claim that this was based on football players sweat).

The story is that was true when it was first being developed in a UF lab. At the time, so the story goes, it was also about as tasty as that sounds.

I doubt the current formula is particularly close.

-B

[keith]

The story is that was true when it was first being developed in a UF lab. At the time, so the story goes, it was also about as tasty as that sounds.

I doubt the current formula is particularly close.

-B

Uhm sugar.

Since all that's needed is an approximately physiological electrolyte solution it's probably still reasonably close. It, or perhaps something like pedialyte, would probably be much easier than sitting with a scale and a beaker. TodG's MMV of course.

On the question of preventing corrosion I would suspect that if you where bothered, a dainty application of high pressure vacuum grease would provide a suitably flexible barrier.

[EldRick]

Seawater/blood/sweat/tears - all similar in chemical composition and concentration, aside from some of the organic byproducts that are not particularly high concentration or extremely corrosive to metals.

Ocean water is usually the easiest of these to obtain in large quantity...

[TodG]

My degree is in chemistry, though I've worked in IT for the last 16 years. I think I can manage making up some simple solutions.

We've been discussing the issue of oxidation in body cord contacts, so I am going to test so of the anti-corrosion treatments used in the electronics industry on body cords: Penetrox, Noalox, and deoxIT for example.

DexoIT in particular is easy to apply and removes existing oxidation. It supposedly has some protection benefits as well. I've been using these products on outdoor antennas for years with good results.

[chase]

A quick search got osmolarity ranges of 49-151 mmol/kg for men and 66-187 mmol/kg for women. You could simply make a saline to those osmolarities with table salt as a starting point.

Then there are things like Urea, lactic acid, Uric acid, ammonia that are going to make a difference.

Of course a simpler plan might be to just drop your test samples in Gatorade (I recall a claim that this was based on football players sweat).

so women have more stink in their sweat? hahaha

[migopod]

so women have more stink in their sweat? hahaha

Not necessarily. While sweat does have a mild odor which depends on the specific constituents, "body odor" is caused by bacterial breakdown of the sweat, not actually from the sweat proper. The stinkier person would be the one who washes less frequently.

[Superscribe]

There's a type of gatorade that's clear, and really salty. There's no sugar in it. I had to drink that crap when i dehydrated on a football field.

I've never had a donkey sweat into a cup and been forced to drink it, but this particular brew of gatorade is a lot like what i think a cup of donkey sweat would taste like. If you go to a physical trainer and then ask them what they woudl make athletes drink if they passed out from dehydration, they'll probably be able to point you to the right stuff.

[rudd]

Urine, close enough and readily available. Urine is 95% water, and also contains Urea, Creatinine, Uric acid, as well as salt and ammonia and other trace elements and hormones.

[Not having a present for Melchett, Blackadder offers a bottle of Baldrick's urine]Blackadder: There was one thing ma'am, a fine WINE from the far east. A most delicious beverage.Queenie: Have a taste, boys; tell us what you think.Sir Walter: It certainly has plenty of nose.Melchett: Oh yes, this is very familiar.Blackadder: You'll be delighted to hear there's an inexhaustible supply of the stuff

[Downtown]

I use to work in the wood coatings business. Furniture...kitchen cabinet finishes....that sort of thing.

Often the topcoats used would need to meet certain requirements. For example kitchen cabinet finishes would need to be resistant to common things found in the kitchen.

I also know that the chemists had some sort of material to test sweat resistance for certain finishes. It stunk to high heaven.

I am not a chemist, but perhaps if you were to do a search related to testing wood finishes, you might find something.

[Emfuser]

Are you seriously having corrosion problems on weapon posts or body cord plugs?

[counterattack]

Seriously, find an original, reliable, scientific source for citation, not a site that allows any yahoo and his dog to edit.

Are you kidding? Wikipedia is pretty solid. If you really need it to be accurate you should look at the edit history and make sure no one has done a wholesale edit. Don't cite wikipedia on your doctoral thesis or use it as a sole source for anything that could be dangerous, of course, but it is an excellent source of accurate information about most things. I am sure their recipe for sweat will be pretty accurate.

-ph

[yearsofwisdom]

yeah its generally pretty accurate.

[LordShout]

http://www.theregister.co.uk/2009/10...ycler_contest/

Not quite what you're looking for but urine and sweat are fairly close. Perhaps you can be conned into acquiring a sample of the aforementioned urine.