Liquid chromatographic-tandem mass spectrometric determination of nonylphenol polyethoxylates and nonylphenol carboxylic acids in surface water.

This paper presents a new LC-MS-MS method for the determination of the concentration of nonylphenol ethoxylates (NPEOs) and nonylphenol carboxylic acids (NPECs) in surface and drinking water using a reversed-phase column, which is fast and specific by nature. This method allows the simultaneous analysis of the two families of compounds in the same extract. Liquid-solid extraction of 100 ml of sample is performed on graphitized carbon black (GCB) cartridges. Reversed-phase chromatography is performed on a C8 column with isocratic elution. The electrospray interface is used to monitor the [M+NH4]+ ion for NPEOs and the [M-H]- ion for NPECs. Detection limits range from 0.01 to 0.05 microg/l for NP(1-17)EOs and are 0.01 microg/l for NP(1-2)ECs. Mean recoveries range from 78 to 107% with relative standard deviations ranging from 6 to 16%. Applicability of the method is demonstrated by results from a monthly sampling of river water at 11 sampling points located downstream of suspected polluting industries in Quebec (Canada).