Analysis of Phenoxycarboxylic Acids and Other Acidic Compounds in Tap, Ground, Surface and Sewage Water at the Low ng/1 Level

Abstract

Solid-phase extraction with RP-C18 phase has been successfully applied for the determination of more than 30 acidic herbicides and related compounds from environmental water samples. Detection of these contaminants was performed after pentafluorobenzylation at the low ng per liter level using gas chromatography/mass spectrometry. With multiple-component SIM programming simultaneous detection of all compounds in one single gas chromatographic run was possible.

Increased reliability of acidic herbicide analysis from water samples with high matrix content was achieved by using a surrogate as well as an internal standard. 2-(4-chlorophenoxy) butyric acid, being a structural isomer of clofibric acid and mecoprop, was chosen as surrogate standard because cloflbric acid was found to be a widespread contaminant in environmental water samples from the Berlin area. Mecoprop, dichlorprop and 1-naphthylacetic acid were also found in field studies of some of these samples. A few examples of positive findings in tap, ground, surface and sewage water samples are presented.

Key Words:

• Acidic herbicides
• pentafluorobenzylation
• solid-phase extraction
• gas chromatography-mass Spectrometry (SIM)
• drinking water
• surface and sewage water