Analysis of pesticides in soy milk combining solid-phase extraction and capillary electrophoresis-mass spectrometry.
In this work, the determination of a group of triazolopyrimidine sulfoanilide herbicides (cloransulam-methyl, metosulam, flumetsulam, florasulam, and diclosulam) in soy milk by capillary electrophoresis-mass spectrometry (CE-MS) is presented. The main electrospray interface (ESI) parameters (nebulizer pressure, dry gas flow rate, dry gas temperature, and composition of the sheath liquid) are optimized using a central composite design. To increase the sensitivity of the CE-MS method, an off-line sample preconcentration procedure based on solid-phase extraction (SPE) is combined with an on-line stacking procedure (i.e. normal stacking mode, NSM). Samples could be injected for up to 100 s, providing limits of detection (LODs) down to 74 microg/L, i.e., at the low ppb level, with relative standard deviation values (RSD,%) between 3.8% and 6.4% for peak areas on the same day, and between 6.5% and 8.1% on three different days. The usefulness of the optimized SPE-NSM-CE-MS procedure is demonstrated through the sensitive quantification of the selected pesticides in soy milk samples.
Hernández-Borges
Javier
J
Department of Analytical Chemistry, Nutrition and Food Science, University of La Laguna, Avda. Astrofísico Fco. Sánchez s/n, 38071 La Laguna, Tenerife, Spain.
Rodriguez-Delgado
Miguel Angel
MA
García-Montelongo
Francisco J
FJ
Cifuentes
Alejandro
A
D019075:Electrophoresis, Capillary / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D010575:Pesticides / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041942:Soy Milk / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D010575:Pesticides