Reversed Electrode Polarity Stacking Sample Preconcentration Combined with Micellar Electrokinetic Chromatography for the Analysis of Carbamate Insecticide Residues in Fruit Juices

Abstract

Reversed electrode polarity stacking mode (REPSM) coupled to micellar electrokinetic chromatography (MEKC) was employed for the simultaneous determination of carbamate insecticide residues in fruit juice samples. A mixture of the studied insecticides (i.e., methomyl, propoxur, carbofuran, carbaryl, isoprocarb, and promecarb) in 10 mmol L −1 phosphate buffer (pH 7.0) was introduced into the capillary tube by hydrodynamic injection at 0.5 psi for 30 s followed by removal of the sample matrix at −15 kV for 0.5 min. The analytes were successfully separated within 8 min using 10 mmol L −1 borate buffer containing 60 mmol L −1 sodium dodecyl sulfate at pH 9.5, and photodiode array detection at 205, 214, and 225 nm. The REPSM-MEKC gave stacking enhancement factors of about 4-13, compared to that without stacking. The limits of detection were in the range 0.01-0.10 mg L −1 , which is acceptable with respect to the maximum residue limits. Good precisions were obtained with relative standard deviation lower than 1.8% (for migration time) and 10% (for peak area). The recoveries for most fruit juice samples were acceptable (>80%). No contamination of the studied carbamates was observed in any sample. The proposed method is simple and effective for preconcentration and removal of matrix interferences in a single step for the determination of the studied carbamate insecticides.

Contemporary sample stacking in analytical electrophoresis

“…The LOD was reduced from 1.7 mg/L to 2.8 μg/L for melamine by the optimum cation‐selective injection step, and from 0.23–1.2 mg/L to 2.4–5.0 μg/L for the other three analytes by the optimum REPSM step. REPSM coupled to micellar MEKC was employed for the simultaneous determination of carbamate insecticide residues in fruit juice samples . The analytes were separated using a BGE containing 10 mM borate and 60 mM SDS at pH 9.5.…”

Recent Advances in the Determination of Pesticides in Environmental Samples by Capillary Electrophoresis

“…The obtained enrichment factors ranged from 479 to 610, and the LODs ranged from 0.02 to 0.04 ng/g. Santalad et al [ 94 ] proposed a reversed-electrode polarity mode coupled MEKC for the analysis of carbamate insecticides residues in fruit juices. This method gave enrichment factors of about 4 to 13 and LODs of 0.01 to 0.10 mg/L.…”

A molecularly imprinted organic-inorganic hybrid monolithic column for the selective extraction and HPLC determination of isoprocarb residues in rice

“…Some analytical methods have been developed for carbamates including IPC, such as GC , ELISA , MEKC , biosensors , HPLC , and HPLC–MS . But the thermal instability of IPC does not permit the direct determination by GC unless it is derived into thermally stable derivatives.…”