Method development and fate determination of pesticide-treated hops and their subsequent usage in the production of beer HENGEL Matt J.; SHIBAMOTO Takayuki; Journal of agricultural and food chemistry，2002, vol. 50, no12, pp. 3412-3418 (24 ref.) Abstract： The fate of residues of seven agrochemicals (chlorfenapyr, quinoxyfen, tebuconazole, fenarimol, pyridaben, and E- and Z-dimethomorph(烯酰吗啉)) from the treatment on hops to the brewing of beer was studied. First, a multi-residue analytical method was developed for the determination of pesticide residues in spent hops, trub, wort, and beer. Each matrix was validated over at least two levels of fortification, for all seven compounds, in the ranges 0.05-5.0, 0.001-1.0, 0.001-0.05, and 0.0005-1.0 ppm for spent hops, trub, wort, and beer, respectively. Recoveries ranged from 73 to 136%. Second, the matrixes prepared from hops, which were treated under commercial practices with each compound, were analyzed using the method developed. The use of treated hops resulted in the carryover of 0.001 ppm of tebuconazole, 0.008 Z-dimethomorph, and 0.005 ppm of E-dimethomorph into the wort. The bulk of the remaining residues of all seven compounds was found on the spent hops. Following fermentation, all compounds were found in levels less than 0.0005 ppm in beer, except Z- (0.006 ppm) and E-dimethomorph (0.004 ppm). Third, when all seven pesticides were spiked prior to the pitching of yeast into clean wort, most of the nonpolar compounds (chlorfenapyr, quinoxyfen, and pyridaben) partitioned into the organic material (trub) which settled to the bottom, while the more polar compounds (fenarimol, tebuconazole, and E- and Z-dimethomorph) were generally distributed evenly between the beer and the trub.
Determination of Fungicides in Fruits and Vegetables by Time-of Flight and Ion Trap LC/MS Imma Ferrer and E. Michael Thurman
Abstract： This application examines the feasibility of the new instrumentation of electrospray and liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) in conjunction with liquid chromatography/ ion trap mass spectrometry (LC/ITMS) to analyze five major fungicides in fruit extracts (apple, lemon, melon, and orange) and in salad vegetables (tomato, broccoli, and pepper). Included are the LC/TOFMS and LC/ITMS MS/MS spectra of five important fungicides (carbendazim, thiabendazole, azoxystrobin, dimethomorph(烯酰吗啉), and triflumizole), the TOF empirical formula and MS/MS fragmentation and diagnostic ion(s) for these fungicides in the matrices of various important fruits and vegetables. A detailed rapid procedure for sample preparation and extraction of these fungicides from the fruit and vegetables is given. Spectral quality at the limit of detection (LOD), linearity, and quantitation of the fungicides in pure solvent and in the fruit and vegetable extracts using TOF and ion trap are provided. Last are the results of the analysis of real samples from the marketplace for these fungicides in fruits and vegetables: apples, oranges, lemons, and melons.
Solid-phase microextraction for the gas chromatography mass spectrometric determination of oxazole fungicides in malt beverages Pilar Viñas, et al.; Analytical and Bioanalytical Chemistry,2008,Volume 391, Number 4, 1425-1431 Abstract: This paper describes a method for the sensitive, selective, and solvent-free determination of six oxazole fungicide residues (hymexazol, drazoxolon, vinclozolin, chlozolinate, oxadixyl, and famoxadone) in malt beverages. Direct immersion solid-phase microextraction (DI-SPME) coupled to gas chromatography with mass spectrometry in the selected ion monitoring mode, GC-MS(SIM), is used. A comparison of the optimal fiber used, a polar carbowax–divinylbenzene 70-μm fiber, and a nonpolar polydimethylsiloxane 100-μm fiber was carried out. Optimal extraction conditions were 60 °C and an extraction time of 30 min under continuous stirring. Desorption was carried out at 250 °C for 5 min. Detection limits ranged from 0.006 to 0.3 μg L−1 at a signal to noise ratio of 3, depending on the compound. The proposed method was successfully applied to malt beverages including malt, beer, and whisky, and none of the samples contained residues higher than detection limits.
Direct determination of Mancozeb（代森锰锌） by photoacoustic spectrometry Sergio Armenta, etal.; Analytica Chimica Acta;Volume 567, Issue 2, 17 May 2006, Pages 255-261 Abstract: A solvent free, fast and environmentally friendly photoacoustic-infrared-based methodology (PAS-FTIR) was developed for the determination of Mancozeb in agrochemicals. This methodology was based on the direct measurement of the transmittance spectra of solid samples and a multivariate calibration model to determine the active ingredient concentration. The proposed partial least squares (PLS) model was made using nine standards prepared by mixing different amounts of kaolin and Mancozeb, with concentrations between 5.43 and 88.10% (w/w).
A hierarchical cluster analysis was made in order to classify the samples in terms of similarity in the PAS-FTIR spectra. From their spectra different commercially available fungicide samples were classified in four groups, attending to the presence of other active ingredients co-formulated with Mancozeb. Different PLS models were applied for the analysis of each group of samples.
So, for samples containing copper oxychloride (group 1), the information in the spectral range from 1543 to 1474 and 1390 to 1269 cm−1 was employed. For samples co-formulated with Fosetyl-Al (group 2) the range between 3334 and 3211 cm−1, corrected with a single point baseline located at 3055 cm−1, was used. For samples containing Metalaxyl (group 3) it was used the information in the spectral range from 1543 to 1474 cm−1 was used to determine Mancozeb. Finally, the range between 1456 and 1306 cm−1 was used for Mancozeb determination in samples containing Cymoxanil (group 4).
The PLS factors used for Mancozeb determination depends on the PLS model employed. 3, 2, 2 and 3 factors were used for Mancozeb determination in commercially available pesticides for groups 1, 2, 3 and 4, respectively. The mean accuracy errors found were 3.1, 2.1, 2.5 and 3.0% for groups 1, 2, 3 and 4, respectively. The developed PAS-FTIR methodology does not consume any solvent, as no sample preparation is necessary it improves the laboratory efficiency without sacrifice the accuracy and avoids the contact of the operator with toxic substances.
Determination of hymexazol in agricultural products by GC-NPD Tamura Y, et al.; Shokuhin Eiseigaku Zasshi. 2008 Jun;49(3):223-7 Abstract: A method for the determination of hymexazol in agricultural produdcts by gas chromatography with a highly sensitive nitrogen-phosphorus detector (GC-NPD) was investigated. Hymexazol was extracted with acetonitrile, and the acetonitrile layer was separated by salting-out. The water layer was loaded onto a Chem-Elut column. Hymexazol in the water layer was adsorbed on the column, and eluted with ethyl acetate. The acetonitrile layer and the eluate were mixed and evaporated. The residue was dissolved in ethyl acetate, and the sample solution was cleaned up on a C18 column. Hymexazol in the eluate was analyzed by GC-NPD with a high-polarity capillary column (DB-FFAP) and highly deactivated inlet liner.Recoveries of hymexazol spiked in agricultural products (tomato, lemon, soybean and other samples) at the level of 0.1 mug/g ranged from 65.0 to 84.7%. The limit of detection was 0.02microg/g.
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