Objective To modify a method combining solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) to determine seven categories of semi-volatile organic chemicals in drinking water.
Methods Water samples (40 L) were extracted by different SPE columns (XAD-2 column, XAD-2/activated carbon tandem columns). XAD-2 was eluted with methanol:acetone (7:3), acetone:hexane (1:1), and dichloromethane in sequence. Activated carbon was eluted with acetone:hexane (1:1) and dichloromethane in sequence. The eluents were dried in air and dissolved in methanol. The concentrations of semi-volatile organic chemicals were determined by GC-MS with internal standard method.
Results The chromatographic peak resolution of the proposed detection method was good, and the linearities of the seven categories of chemicals were good within the range of 0.05-5 μg/mL. The recoveries of 115 chemicals using XAD-2/activated carbon tandem columns were improved. The recoveries of organochlorine pesticides, organonitrogen pesticides, polychlorinated biphenyls, phthalate esters, and high-molecular-weight polycyclic aromatic hydrocarbons were mostly in the range of 70%-110%, and the precisions were below 20%. The recoveries of most nitrosamines and high volatile phenols were low. The method's detection limits satisfied the detection requirements of drinking water.
Conclusion The enrichment efficiency of XAD-2/activated carbon tandem columns is higher than that of XAD-2 column alone. The modified SPE-GC-MS method is sensitive for determination of seven categories of semi-volatile organic chemicals in drinking water, and is suitable for the enrichment and detection of large-volume drinking water samples.
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