Multiresidue Analysis of Nitrogen-containing and Sulfur-containing Pesticides in Agricultural Products Using Dual-column GC-NPD/FPD.

Abstract

We investigated simultaneous analytical methods for pesticide residues in large numbers of agricultural products samples. Extraction of each sample with acetonitrile was followed by a salting-out step using a graduated cylinder. The test solution was cleaned up with gel permeation chromatography (GPC), which separated the pesticide eluate into 2 fractions, and then with a tandem mini-column. Analysis was done with a dual-column GC equipped with a dual NPD and FPD (S mode) detector. Use of the Siltek TM -deactivated liner, guard column, and Y connector, and Silcosteel ῌ -treated NPD jet was e#ective for preventing the breakdown of sulfur-containing pesticides.Recoveries of 87 nitrogen-containing and sulfur-containing pesticides from fortified spinach, tomato, apple, strawberry and brown rice, ranged from 71 to 127 with RSD values of 1ῑ24, except for recoveries of aldicarb, amitraz, ethiofencarb, imazalil, propamocarb and triflumizole. Detection limits of pesticides were very good (0.3ῑ5 ppb (NPD) and 2ῑ20 ppb (FPD)) for routine analysis of pesticide residues in foods.Surveillance of pesticides in agricultural products was carried out by using the present method. From 22 out of 33 samples, 21 pesticides (43 in total) were detected. The results indicated that the present method can be applied as an e$cient and reliable means for monitoring pesticide residues in agricultural products.

Determination of Tetraconazole and Diniconazole Fungicide Residues in Tomatoes and Green Beans by Capillary Gas Chromatography

“…10) 2) It has a lower detection limit (0.001 ppm for both tetraconazole and diniconazole), rather than 0.03 ppm 12) or 0.01 ppm. 14,22) 3) It is speciˆc for the two compounds, and thus gave the best recovery rate for both, while other methods 6,8,10,11,16,19,28,32,33) used for multipesticide screening are nonspeciˆc for the studied compounds. 4) GC-ECD is comparatively economical, and more available than GC-MS-MS 7,9,10,24,28) or GC-MS. 19,23)…”

“…Estimation of the residual amounts of tetraconazole and diniconazole is largely dependent on GC methods using NPD, 11) FPD, 11,25) ECD, 12,14,25) FTD, 22) TSD, 25) GC-MS, 19,23) or GC/MS/MS, 10,24) although better precision and sensitivity values are obtained with the LP-GC/MS/MS approach (lowpressure tandem mass gas chromatography). 7 9,28) HPLC methods are used to a lesser extent, 4,12,16,26,27) LC/MS is used for both fungicides, 33) and LC/MS/ MS (liquid chromatography tandem mass spectrometry) is also used.…”

“…The clean-up step for tetraconazole is column chromatography, 10,12) gel permeation chromatography, 11) or solid phase extraction. 16,32) In some cases no clean up is required.…”

“…5) Several schemes have been provided for extraction of both fungicides from plant materials and for their clean-up from interfering impurities. Extracting solvents used for tetraconazole varied from ethylacetatecyclohexane, 6) dichloramethane, 7 10) acetonitrile, 11) acetone, 1) and toluene, 2) while for diniconazole acetone, 12 14) hexane, chloroform, 15) or ethyl acetate 16) were used. Other methods for extraction include matrix solid-phase dispersion, 17) and solid-phase extraction 18) for tetraconazole and stir bar sorptive extraction, 19) solid bonded-phase extraction, 20) and supercritical ‰uid extraction 21) for diniconazole.…”

Development and diffusion of a systematic method for determining multiple pesticide residues in agricultural products

“…24,27,28) Grapefruit was produced by natural crossing pomelo and orange, so it is necessary to note that similar interfering peaks appear over the entire product ions produced from the protonated molecule of imazalil on the chromatograms of the test solution of pomelo by LC conditions. In addition to the MS/MS system, EI-SIM/Scan mode GC-MS, 9) negative chemical ionization (NCI)-SIM/Scan mode GC-MS, 17) dual-column GC-ECD/ECD, 3,11) dual-column GC-FPD/NPD, [4][5][6] ESI-SIM/Scan mode LC-MS with diode-array detection (DAD), 13,14) and HPLC with post-column FLD for residual N-methyl carbamate pesticides, 24,29) were also adopted. Thus, the systematic method using plural separation and detection systems has been constructed.…”