title: Gas chromatographic determination of pesticide residues in white mustard.
abstract: A new analytical method employing gas chromatography coupled to electron capture and nitrogen phosphorus detection (GC-ECD/NPD) has been developed and validated for the screening and quantification of 51 pesticides in a matrix of high chlorophyll content - white mustard (Sinapis alba L.). For preparation of the sample extract, the citrate buffered QuEChERS procedure was followed. However certain changes were made to adapt the method to our needs and available laboratory resources. The sample size was reduced to 5 g, 10 mL water was added and exchange of solvent before GC analysis was done. The samples spiked with the target pesticides at the concentration level 0.01 mg/kg and a higher level (depending on the compound) yielded average recoveries in the range of 70-120% with relative standard deviations (RSDs) 0-19% except for HCB, S-metolachlor and teflubenzuron, and displayed very good linearity (R(2)>0.99) for nearly all the analytes. Limit of quantification was 0.01 mg/kg for the majority of the analytes. The expanded measurement uncertainties were estimated employing a "top-down" empirical model as being between 6% and 32% and yielding an average value of 18% (coverage factor k=2, confidence level 95%).
authors.affiliation: Institute of Plant Protection - National Research Institute, Regional Experimental Station, Gen. Langiewicza 28, 35-101 Rzeszów, Poland. Electronic address: m.borowiec@iorpib.poznan.pl.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Słowik-Borowiec
authors.affiliation: Institute of Plant Protection - National Research Institute, Regional Experimental Station, Gen. Langiewicza 28, 35-101 Rzeszów, Poland. Electronic address: e.szpyrka@iorpib.poznan.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Szpyrka
authors.affiliation: Institute of Plant Protection - National Research Institute, Władysława Węgorka 20, 60-318 Poznań, Poland. Electronic address: s_walorczyk@tlen.pl.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Walorczyk
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002849:Chromatography, Gas / Q000379:methods*; D009149:Mustard Plant / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*
chemical_list: D010573:Pesticide Residues; D010575:Pesticides
keywords: Gas chromatography; Method validation; Pesticide residue analysis; White mustard