Problem with Lactic acid determination

[Awni-QC]

Hallo
How may Lactic acid be Determined in presence of Salicylic acid and Collodion ?

[Consumer Products Guy]

Use organic acid column, conductivity detector, acidic aqueous mobile phase. Also check USP/NF monograph, as lactic acid is a combination of lactic acid and lactic acid lactate.

[SIELC_Tech]

Lactic acid exists as a mixture of oligomers. If you need to analyze it as a single compound you might need to hydrolize oligomers. Here is the method for analysis of lactic acid. It is retained on Primesep mixed-mode column:

http://www.sielc.com/compound_156.html

For lactic acid is self you can use Primesep D or Primesep SB column similar to glucoronic acid (similar pK and polarity):

http://www.sielc.com/compound_251.html

[JA]

Answers have been given to the question "How may Lactic acid be Determined."

Is any attention necessary to the presence of Collodion (nitrocellulose) and any deleterious affects it might have when being repeatedly injected into a chromatographic column?

[Awni-QC]

Is any attention necessary to the presence of Collodion (nitrocellulose) and any deleterious affects it might have when being repeatedly injected into a chromatographic column?

Yes it is necessary to pay attention to the presense of salicylic acid and collodion
thanks

[Awni-QC]

I changed lactic acid and Oligomers into Sodium Lactate, and nitrous groups of collodion into Sodium nitrite, then used following chromatographic conditions:
Concentration: 0.8 mg/ml approximatly, Conductivity detector, PRP-X110 HAMILTON COLUMN, 1.0 ml/min.,
37 BAR pressure, Rt was 11.2 minutes.