Continuous‐flow microwave‐assisted extraction coupled with online single drop microextraction prior to GC‐MS for determination of amide herbicides in rice samples

Abstract

A rapid method based on continuous‐flow microwave‐assisted extraction and online single drop microextraction was first developed and applied to the determination of amide herbicides in rice. The present method has the advantages of both continuous‐flow microwave‐assisted extraction and online single drop microextraction, which combines extraction, separation, preconcentration, and sample introduction in one step. By continuous‐flow microwave‐assisted extraction, analytes were first extracted from the rice samples using 15% methanol–water, and then concentrated into single drop. The microdrop was retracted into microsyringe and directly analyzed by gas chromatography with mass spectrometry without any filtration or clean‐up process. The method greatly simplifies the sample treatment procedure, reduces consumption of toxic organic solvent, and extends the application of single drop microextraction to complex solid samples. Several parameters were optimized by Box–Behnken design. Under optimal experimental conditions, good linearity was observed in the range of 2.0–500.0 μg/kg. The limits of detection and quantification were in the range of 0.3–1.5 and 1.1–5.1 μg/kg, respectively. The intra‐ and inter‐day precisions were between 1.9 and 4.8%. The present method was used to the analysis of real rice samples, and the recoveries of analytes were between 80.3 and 102.3% with the relative standard deviations ranging from 1.1 to 6.9%.

A microwave‐assisted extraction method combined with magnetic ionic liquid‐based dispersive liquid–liquid microextraction for the extraction of chloramine–T from fish samples prior to its determination by high‐performance liquid chromatography

“…Microwave irradiations are utilized to heat the mixture of sample and extraction solvent in order to increase the migration rate of analytes from the solid sample into extractant. Furthermore microwave irradiations can penetrate into the solid matrix effectively [19]. This combined approach profits the merits of both MAE and DLLME methods, simultaneously.…”

Single‐drop microextraction technique for the determination of antibiotics in environmental water

“…The method based on online SDME was first developed by Wu and Li to determine amide herbicides. The present method combines extraction, separation, preconcentration, and sample introduction in one step, and under optimal experimental conditions, good linearity was observed in the range of 2.0–500.0 μg/kg [113].…”

Combination of microwave‐assisted extraction with dispersive micro solid‐phase extraction as an efficient sample pretreatment method for the extraction of some antiparasitic drugs from cow liver, meat, and kidney samples

“…Generally, in spite of the sufficient sensitivity of these instruments, prior to analysis of the foodstuffs, a sample pretreatment step is needed in order to get rid of interfering compounds originating from sample matrices and preconcentration of the analytes (guarantee determination of low concentrations) [14][15][16]. Microwaveassisted extraction (MAE) [17] and dispersive micro SPE (DμSPE) [18] are among the extensively employed sample pretreatment methods that were developed to overcome the difficulties of traditional liquid-liquid extraction (consuming high volumes of toxic organic solvents) and SPE (clogging the cartridges throughout the extraction process and being tedious and time-consuming). In DμSPE, a low amount of an adsorbent is directly added to the sample solution and dispersed into it with the help of manual shaking or vortex agitation which creates a very high contact area between the adsorbent and adsorbate and makes the method efficient and time-saving [19][20][21][22][23][24][25].…”