Sensitive Gas-Liquid Chromatographic Method for Asulam Residues in Peaches

1980 ◽  
Vol 63 (3) ◽  
pp. 511-516
Author(s):  
Promode C Bardalaye ◽  
Neal P Thompson ◽  
David A Carlson
Keyword(s):  
Analytical Method ◽  
Chemical Ionization ◽  
Parent Compound ◽  
Coupling Reaction ◽  
Gas Liquid Chromatography ◽  
Ionization Mass ◽  
Liquid Chromatographic Method ◽  
The Common ◽  
Liquid Chromatographic ◽  
Colorimetric Procedure

Abstract The current analytical method for determining residues of the herbicide asulam (methyl (4-aminobenzenesulfonyl) carbamate) is the nonspecific colorimetric procedure based on the coupling reaction of N-1-naphthylethylenediamine with the diazotized amine. A new analytical method for determining the residues of this herbicide and its 2 known major metabolites, acetylasulam and sulfanilamide, in peaches has been developed and evaluated using gas chromatography with an N-P detector. The method is based on the hydrolytic conversion of the parent compound and the known metabolites to the common product sulfanilamide which is then analyzed by gas-liquid chromatography as its per N-methylated derivative. The identity of the derivative has been confirmed by chemical ionization mass spectrometry. The method was tested by using fortified crop extracts and also by analyzing crop treated by postemergent application of the herbicide for weed control. Sensitivity of the method is 5 ng and the detection limit in the crop is 0.1 ppm. Recoveries ranged from 70 to 80% from peaches at fortification levels of 1, 5, and 10 ppm. At a fortification level of 0.1 ppm the recovery is 50-60%.

Evaluation and Confirmation of an Alkylation-Gas-Liquid Chromatographic Method for the Determination of Carbamate and Urea Herbicides in Foods

1976 ◽  
Vol 59 (5) ◽  
pp. 1061-1065
Author(s):  
James F Lawrence
Keyword(s):  
Sodium Methoxide ◽  
Chromatographic Method ◽  
Parent Compound ◽  
Sodium Hydride ◽  
Food Type ◽  
Gas Liquid Chromatography ◽  
Liquid Chromatographic Method ◽  
Herbicide Concentration ◽  
Liquid Chromatographic

Abstract An alkylation technique using methyl iodide and sodium hydride in dimethyl sulfoxide has been evaluated for 3 carbamate and 7 urea herbicides in 9 foods. Recoveries ranged from 56 to 113%, depending on herbicide, concentration, and food type. Reproducibility was about ±6% at 0.1 and 1.0 ppm. Identities of the herbicides were confirmed at these and lower levels by cleaving the aniline moiety from the alkylated herbicides with sodium methoxide in methanol, followed by gas-liquid chromatography on the same column as the parent compound. An electrolytic conductivity detector in the nitrogen mode was used for all analyses. Minimum detectable levels were in the range of 0.005–0.01 ppm in the foods studied.

Quantitation of Polychlorinated Biphenyl Residues by Electron Capture Gas-Liquid Chromatography: Reference Material Characterization and Preliminary Study

1978 ◽  
Vol 61 (2) ◽  
pp. 272-281
Author(s):  
Leon D Sawyer
Keyword(s):  
Electron Capture ◽  
Material Characterization ◽  
Chemical Ionization ◽  
Polychlorinated Biphenyl ◽  
Collaborative Study ◽  
Gas Liquid Chromatography ◽  
Ionization Mass ◽  
Preliminary Study ◽  
The Individual ◽  
Liquid Chromatographic

Abstract Weight per cent compositions of individual peaks of Aroclors 1016, 1242, 1248, 1254, and 1260 were determined under standard gas-liquid chromatographic (GLC) conditions. The GLC peak compositions were determined by using a Hall electrolytic conductivity detector for chlorine measurement and chemical ionization mass spectrometry with single ion monitoring for molecular weight characterization. The Aroclors used are available as reference materials for individual peak quantitation of polychlorinated biphenyl (PCB) residues by electron capture GLC. On the basis of a limited interlaboratory study and a collaborative study, the individual peak method shows improved interlaboratory precision and/or accuracy in PCB quantitation over existing methods.

Gas-Liquid Chromatographic-Mass Spectrometric Confirmation of Endosulfan and Endosulfan Sulfate in Apples and Carrots

1981 ◽  
Vol 64 (5) ◽  
pp. 1208-1210
Author(s):  
Perry S Wilkes
Keyword(s):  
Mass Spectra ◽  
Chemical Ionization ◽  
Mass Range ◽  
Mass Spectrometric ◽  
Chromatographic Retention ◽  
Gas Liquid Chromatography ◽  
Endosulfan Sulfate ◽  
Gasliquid Chromatography ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract A gas-liquid chromatography-mass spectrometric (GLC-MS) procedure is described for the confirmation of endosulfan I, endosulfan II, and endosulfan sulfate in apples and carrots. After extraction, cleanup, and determination by electron capture gasliquid chromatography using current AOAC methodology, residues are confirmed by GLC-MS. The chemical ionization (CI) mode is used with methane as a reagent gas. Each residue is confirmed by a scan of only 4 regions of its mass spectrum rather than the full mass range. The 4 mass regions for the 2 endosulfan isomers are 274-280, 340-346, 368-374, and 404-412 atomic mass units (amu). For endosulfan sulfate, the mass regions are 286-294, 322-330, 384-392, and 420-428 amu. Four ions and their chlorine isotopic distributions are detected for each compound by this scanning technique. This method was developed by using carrots and apples to which had been added 0.1 ppm (50% of the current legal tolerance on carrots) of each of the 3 pesticides. The gas chromatographic retention times and the mass spectra of the 4 mass regions specified for the 3 pesticides were compared to those of reference standards injected under identical GLC-MS conditions and were used as the basis for confirming identity of the 3 compounds.

Separation and Analysis of the Pyrethrins by Combined Gas-Liquid Chromatography-Chemical Ionization Mass Spectrometry

1977 ◽  
Vol 60 (3) ◽  
pp. 685-689 ◽  
Author(s):  
Roy L Holmstead ◽  
David M Soderlund
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Chemical Ionization ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Gas Liquid Chromatography ◽  
Ionization Mass ◽  
Total Extract ◽  
Naturally Occurring ◽  
Selective Ion Monitoring

Abstract Pyrethrins, the 6 naturally occurring insecticidal esters of pyrethrum extract, were analyzed by combined gas-liquid chromatography-chemical ionization mass spectrometry. Separation was best on an OV-25 column with temperature programming. The chemical ionization mass spectra for the 6 esters as well as for the thermally isomerized pyrethrins I and II are reported and discussed. Using selective ion monitoring, a lower limit of detectability of all 6 esters was 114 ng of total extract injected on the column.

Gas-Liquid Chromatographic/Mass Spectrometric Screening Method for T-2 Toxin in Milk

1979 ◽  
Vol 62 (6) ◽  
pp. 1274-1280
Author(s):  
George J Collins ◽  
Joseph D Rosen
Keyword(s):  
Mass Spectrometry ◽  
Electron Impact ◽  
Chemical Ionization ◽  
Impact Ionization ◽  
Trimethylsilyl Ether ◽  
Screening Method ◽  
Internal Standard ◽  
Electron Impact Ionization ◽  
Gas Liquid Chromatography ◽  
Ionization Mass

Abstract A method for the analysis of T-2 toxin in milk is presented. Ethyl acetate extracts of milk samples which had been spiked with T-2 toxin were purified by thin layer chromatography and derivatized with N,O-bis(trimethylsilyl)acetamide to produce the T-2 toxin trimethylsilyl ether (T-2 toxin-TMS). N,O-bis(trimethylsilyl-d9)acetamide was used to make T-2 toxin d9-trimethylsilyl ether (T-2 toxin-d9TMS) which was added to the derivatized milk extract as an internal standard. Samples were analyzed by combined gas-liquid chromatography/mass spectrometry using either electron impact ionization or chemical ionization mass spectrometry. In electron impact ionization analyses, simultaneous monitoring of the T-2 toxin-TMS fragment ion at m/z 436 and the T-2 toxin-d9TMS fragment ion at m/z 445 gave a T-2 toxin-TMS detectability estimated at 6 μg/kg. In chemical ionization analyses, the T-2 toxin-TMS fragment ion at m/z 377 and the T-2 toxin-d9TMS fragment ion at m/z 386 were simultaneously monitored to give a T-2 toxin-TMS detectability estimated at 3 μg/kg. Average recovery was 85% at 200 μg/kg and 65% at 20 μg/kg.

Quantitative Determination of L-Ascorbic Acid by Gas-Liquid Chromatography

1974 ◽  
Vol 57 (6) ◽  
pp. 1346-1348
Author(s):  
Janis E Schlack
Keyword(s):  
Ascorbic Acid ◽  
Lead Acetate ◽  
Chromatographic Method ◽  
Ethanol Solution ◽  
Lead Salt ◽  
Gas Liquid Chromatography ◽  
Trimethylsilyl Derivative ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method for L-ascorbic acid in foods and food products has been devised. Ascorbic acid is extracted into an ethanol solution, precipitated with lead acetate, regenerated from the lead salt as its trimethylsilyl derivative, and chromatographed on an SE- 30 column. Recoveries averaged 100.1%; the standard deviation was ±0.23%.

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