A fast method of analysis for 20 representative pesticides was developed using low-pressure gas chromatography-mass spectrometry (LP-GC-MS). No special techniques for injection or detection with a common quadrupole GC-MS instrument were required to use this approach. The LP-GC-MS approach used an analytical column of 10 m x 0.53 mm I.D., 1 microm film thickness coupled with a 3 m x 0.15 mm I.D. restriction capillary at the inlet end. Thus, the conditions at the injector were similar to conventional GC methods, but sub-atmospheric pressure conditions occurred throughout the analytical column (MS provided the vacuum source). Optimal LP-GC-MS conditions were determined which achieved the fastest separation with the highest signal/noise ratio in MS detection (selected ion monitoring mode). Due to faster flow-rate, thicker film, and low pressure in the analytical column, this distinctive approach provided several benefits in the analysis of the representative pesticides versus a conventional GC-MS method, which included: (i) threefold gain in the speed of chromatographic analysis; (ii) substantially increased injection volume capacity in toluene; (iii) heightened peaks with 2 s peak widths for normal MS operation; (iv) reduced thermal degradation of thermally labile analytes, such as carbamates; and (v) due to larger sample loadability lower detection limits for compounds not limited by matrix interferences. The optimized LP-GC-MS conditions were evaluated in ruggedness testing experiments involving repetitive analyses of the 20 diverse pesticides fortified in a representative food extract (carrot), and the results were compared with the conventional GC-MS approach. The matrix interferences for the quantitation ions were worse for a few pesticides (acephate, methiocarb, dimethoate, and thiabendazole) in LP-GC-MS, but similar or better results were achieved for the 16 other analytes, and sample throughput was more than doubled with the approach.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.
"Some efforts have already been made to adopt low-pressure gas chromatography in pesticide residues analysis. Maštovská et al. (2001) optimised LP-GC/MS conditions for the analysis of 20 pesticides in carrots and the researchers from the University of Almeria (Spain) described some applications of LP-GC in conjunction with tandem mass spectrometry (González-Rodríguez et al 2002; Arrebola et al. 2003; Martínez Vidal et al. 2003). "
[Show abstract][Hide abstract] ABSTRACT: A method for the fast identification of trace levels of pesticide residues in agricultural crops was developed using low pressure gas chromatography/mass spectrometry (LP-GC/MS). The final chromatographic determination took 12 min-utes per sample while conventional GC/MS required at least 30 minutes. Also, im-proved peak shapes for dichlorvos, dimethoate, chlorothalonil, pirymethanil, pirimicarb, carbaryl, myclobutanil, flusilazole tebuconazole, fenarimol and ipro-dione were obtained which generally enabled lower limits of detection. The method was successfully applied to analysis of more than 40 pesticides in 120 sam-ples of fruits, vegetables and cereals. With the aid of LP-GC/MS the number of samples analysed on the particular instrument could be at least doubled.
[Show abstract][Hide abstract] ABSTRACT: Practical applications of fast gas chromatography (GC) with time-of-flight mass spectrometry (TOFMS) are presented. A narrow-bore column (0.10-mm i.d.) is used to analyze over 100 specific polychlorinated biphenyl congeners in an Aroclor mix and a sediment sample in 10.5 min. Sample preparation is minimized for the sediment to more closely match the speed advantage gained by using fast GC-TOFMS. The possibility of using a 0.53-mm-i.d. column operated under vacuum-outlet conditions for fast GC-TOFMS is established for Aroclors and a suite of environmental contaminants. Fast acquisition rates and automated peak-find and spectral deconvolution capabilities are demonstrated for TOFMS.