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 μg/l for NP(1–17)EOs and are 0.01 μg/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).