کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1207598 1493749 2007 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On-line preconcentration strategies for analyzing pesticides in fruits and vegetables by micellar electrokinetic chromatography
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
On-line preconcentration strategies for analyzing pesticides in fruits and vegetables by micellar electrokinetic chromatography
چکیده انگلیسی

Five pesticides (fludioxonil, procymidone, pyriproxyfen, dinoseb and carbendazim) were separated in reversed migration micellar electrokinetic chromatography (RM-MEKC) using 20 mmol l−1 phosphate buffer at pH 2.3, containing 25 mmol l−1 sodium dodecylsulfate and 10% methanol. Three on-line concentration strategies, sweeping (SW), normal stacking with reversed migration and a water plug (SRW) and stacking with reverse migration and removal of sample matrix using polarity switching (SRMM), were compared. About 10-, 30- and 50-fold increases in detection sensitivity, compared with standard hydrodynamic injection (5 s at 0.5 psi), were observed with SW, SRW and SRMM, respectively. Limits of detection (LODs) ranged from 0.002 to 0.03 μg ml−1 using only the on-line preconcentration procedures without any off-line concentration of the extract. A solid-phase extraction (SPE) procedure, for previous isolation and concentration of the analytes, was used in combination with any of the proposed on-line preconcentration strategies, which achieves the determination of pesticides at limits of quantification (LOQs) lower than 0.01 mg kg−1. The recoveries obtained by SPE in samples spiked at 0.01 mg kg−1 were between 70 and 100%, with RSDs between 10 and 18% using SRMM. Samples of fruits and vegetables were taken from the market, extracted by the proposed procedure and analyzed with RM-MEKC with the on-line strategies.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Chromatography A - Volume 1153, Issues 1–2, 15 June 2007, Pages 104–113
نویسندگان
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