WEF Discussion Forums : Laboratory Management and Technical Issues : Volatile Acids

Thu, 05 Jan 2012 14:56:35 GMT

We recently had to switch contract labs and have found the the new labs VA is about 10 times higher than the old lab. The old lab uses method SM 5560C and the new lab uses SM 2310B. I was wondering if anyone has any experience with both of these methods, and if this could really just be the difference between the 2 methods? Thanks

for any input.

Fri, 06 Jan 2012 18:18:59 GMT

Method 2310 is a test for Acidity - which is the quantitative capacity to react with a strong base to a designated pH. Acidity is measured as mg CaCO3/L.

Method 5560 is a test for Organic or Volatile Acids - volatile fatty acids are classified as water-soluble fatty acids that ca be distilled at atmospheric pressures. This test is a control test to determine the health for anaerobic digestion. This measures the concentrations of the volatile fatty acids in mg/L.

I am not sure what you are using the test for but if you are needing Volatile Acids then the contract lab should perform the 5560C or D.

Mon, 09 Jan 2012 20:50:57 GMT

I know, this doesn't sound right, but this is what info they are sending us (at least what little info we have now, working on more) What they are referencing is a combo of 2310B & 2320B and also referencing an EPA method, I think is so that the VA and ALK can be run in 1 shot. I guess it is the same as what is posted for the state of Vermont (which I can't find right now to post the actual link).

worker bee

Fri, 13 Jan 2012 16:05:06 GMT

I would suggest that you discuss the analysis and method with the contract lab. Pick a lab that will do the analysis you want.

Volatile Acids ( Organic acids) is a measure of low molecular weight organic acids such as acetic, propionic, butyric, iso butyric, valeric, and isovaleric acids. Method 5560 should be used. Results are reported as acetic acids normally.

Method 2310 is a measure of inorganic acids as CaCO3 and not the same as VA. Some organic acids might be titrated and add to the total acidity, inorganic acids, though.

2320 is alkalinity.