Simultaneous Determination of Parathion, Malathion, Diazinon, and Pirimiphos Methyl in Dried Medicinal Plants Using Solid-Phase Microextraction Fibre Coated with Single-Walled Carbon Nanotubes

Reza Ahmadkhaniha,Mona Salimi,Parisa Sarkhail,Noushin Rastkari,Nasrin Samadi

doi:10.1100/2012/627607

Abstract

A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r 2 ≥ 0.993) over the concentration ranges from 1.5 to 300 ng g−1, and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g−1. For parathion and malathion, the linear range and limit of detection were 2.5–300 (r 2 ≥ 0.991) and 0.5 ng g−1, respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350°C), and longer lifespan (over 250 times) than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples.

Highlights

Medicinal plants are widely consumed for pharmaceutical preparations and as a supplement for dietetic products and especially for “self-medication” in the general population, and they are commonly used in health care products, food additives, or supplementary foods
We have developed a new solid-phase microextraction (SPME) fibre using single-walled carbon nanotubes (SWCNTs) as adsorbent, which successfully applied for headspace solidphase microextraction (HS-SPME) of target compounds in different matrices [15,16,17,18]
The surface characteristics of the SWCNT and PDMS fibres were investigated by scanning electron micrograph (SEM) technique [15]

Summary

Introduction

Medicinal plants are widely consumed for pharmaceutical preparations and as a supplement for dietetic products and especially for “self-medication” in the general population, and they are commonly used in health care products, food additives, or supplementary foods. Pesticide residues in herbal medicinal materials become pitfalls in safety and present obstacles to be acknowledged by the international community. The feasibility of SWCNTs adsorbent for headspace SPME of OPPs in dried medicinal plant samples was investigated. Potential factors affecting the extraction efficiency were optimized, and the analytical performance of the developed SWCNT-coated fibre was compared with that of commercial PDMS fibre, which was frequently used for determination of OPPs in different matrices [1, 19,20,21]. The application of the developed method in OPPs residual analysis was shown by the simultaneous determination of trace amounts of parathion, malathion, diazinon, and pirimiphos methyl in some medicinal plant samples

Experimental

Results and Discussion

Conclusion