Detecting naphthenic acids in waters by gas chromatography-mass spectrometry.
Naphthenic acids (general formula C(n)H(2n+Z)O(2)) are water-soluble, toxic compounds found in petroleum and bitumen. Some of the current methods for detecting these acids in waters depend on measuring the presence of the carboxylic acid functional group, and therefore many of these methods also detect naturally occurring carboxylic acids that are not naphthenic acids. We report a procedure that includes liquid-liquid extraction, cleanup, and derivatization to form t-butyldimethylsilyl esters prior to gas chromatography-mass spectrometry (GC-MS) analysis. Using low- and high-resolution MS to detect the ion C(15)H(27)O(2)Si(+) (nominal m/z=267) is an excellent indicator of the presence of naphthenic acids at concentrations > or =10microgL(-1).
Merlin
Mireya
M
Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 2W2, Canada.
Guigard
Selma E
SE
Fedorak
Phillip M
PM
D002264:Carboxylic Acids / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D009281:Naphthalenes / Q000032:analysis*; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction; D014874:Water Pollutants, Chemical / Q000032:analysis*
D002264:Carboxylic Acids; D009281:Naphthalenes; D014874:Water Pollutants, Chemical; C046170:naphthenic acid