Sensitive and accurate determination of 168 micropollutants including pharmaceuticals and pesticides in surface water and wastewater samples with direct injection using jet stream ESI LC-MS/MS

Abstract

ABSTRACT This paper is to exhibit validation studies of developed analytical method for the simultaneous determination of 168 micropollutants including pharmaceuticals and several pesticides in surface water and wastewater samples with direct injection using jet stream ESI LC-MS/MS. Method development in the LC-MS/MS system was carried out to determine the best chromatographic column and MS conditions allowing the retention and the maximum number of analytes. The linearity of the analytical response across the studied range of 0.5–500 ng/L was evaluated as excellent, with correlation coefficients higher than 0.995 with a few exceptions such as bentazone (0.993), carbyl (0.994), etoxazole (0.994), fenthion (0.978), fludioxonil (0.985), metformin (0.844), metolachlor (0.992), naproxen (0.990) and sulfametoksazol (0.993). The LOD of 67% (113 analytes) of the analytes included important pesticides and pharmaceuticals was in the range of 0.5–2.0 ng/L. The recoveries of analytes in wastewater ranged mostly from 80% to 120% and RSD (%) values changed generally between 1 and 10. The recoveries of analytes in surface water were in the range of 80% and 100% and relevant RSD (%) values changed generally between 2 and 8. Repeatability studies were performed in the wastewater injected with three different concentrations of 25, 50 and 100 ng/L in seven measurements and in surface water with 100 ng/L in eight measurements. Reproducibility studies were performed by seven analyses on two different days. The matrix effect was further evaluated for ion suppression between the standards prepared in pure solvent and the standards prepared in the matrix, and the matrix effect was found in a range of 16–22%. In real samples, Propiconazole, Imidachloprid, Quinoxyfen, Carbendazim and Prochloraz are the five compounds detected in the highest amount in real samples. The results demonstrate that this LC-MS/MS method is suitable for the determination of pharmaceuticals and several pesticides in water samples.