Determination of organophosphorus pesticides by gas chromatography with mass spectrometry using a large‐volume injection technique after magnetic extraction

Abstract

A fast and efficient method was developed for the extraction and determination of organophosphorus pesticides in water samples. Organophosphorus pesticides were extracted by solid-phase extraction using magnetic multi-walled carbon nanotubes and determined by gas chromatography with ion-trap mass spectrometry. Parameters affecting the extraction were investigated. Under optimum conditions of the method, 10 mg magnetic multi-walled carbon nanotubes were added into 10 mL sample. After 2 min, adsorbent particles settled at the bottom of test tube with a magnet. After removing aqueous supernatant, the analytes were desorbed with acetonitrile. Then, 70 μL of acetonitrile phase was injected into the gas chromatography and mass spectrometry system that had an ion-trap analyzer. To achieve high sensitivity, the large-volume-injection technique was used with a programmed temperature vaporization inlet, and the ion-trap mass spectrometer was operated in single ion storage mode. Under the best conditions, the enrichment factors and extraction recoveries were in the range of 113-124 and 74-103%, respectively. The limits of detection were between 3 and 15 ng/L, and the relative standard deviations were < 10%. This method was successfully used for the determination of organophosphorus pesticides in dam water, lagoon water, and river water samples with good reproducibility and recovery.

Evaluation of the matrix-like effect in multiresidue pesticide analysis by gas chromatography with tandem mass spectrometry

“…On the other hand, when the three deuterated polycyclic aromatic hydrocarbons were used as ISs, the normalized RRFs of solutions B, C, and D tended to be higher. It has been reported that TPP [8][9][10]16,18,19,28,29], NPH-d 8 [11,12,31], PHN-d 10 [11,12], and FLA-d 10 [11] are suitable for use as GC-MS(/MS) IS compounds in multiresidue pesticide analysis. However, our results clearly show that the presence of coexisting pesticides significantly alters the RRFs, and the four-candidate IS compounds are unable to adequately compensate for the matrix-like effect in solvent standard solutions.…”

“…In addition, four IS candidates-triphenyl phosphate (TPP), naphthalene-d 8 (NPH-d 8 ), phenanthrene-d 10 (PHNd 10 ), and fluoranthene-d 10 (FLA-d 10 ), widely used for GC analysis-were also selected and evaluated. TPP has been widely reported to be suitable for use as a universal GCamenable IS for the multiresidue pesticide analysis of food samples [8][9][10]16,18,19,28,29]; thus, it was expected to be an excellent IS candidate to compensate for the matrix-like effect.…”

Development of a dispersive liquid–liquid microextraction method with a new sequence of steps and its comparison with a conventional method

“…Also, these compounds contaminate surface water, soil, etc. . So, it is necessary to develop simple, rapid, and sensitive analytical methods for determination of trace OPP residues in foods and environmental samples.…”

Enrichment and determination of polybrominated diphenyl ethers in environmental water samples by magnetic solid‐phase extraction with core–shell magnetic carbon microspheres before gas chromatography with mass spectrometry

“…Magnetic solid‐phase extraction (MSPE) based on magnetic nanoparticles has drawn great attention in sample preparation because of its rapidity, compatibility and ease of operation . In particular, the development of MSPE overcomes the limitations of conventional SPE processes . Compared with traditional SPE, MSPE is based on the adsorption and release of target analytes by a small amount of magnetic or magnetizable sorbents that is dispersed in solution .…”