Gas Chromatography with Microcoulometric Detection for Pesticide Residue Analysis

1964 ◽  
Vol 47 (5) ◽  
pp. 845-859
Author(s):  
Jerry Burke ◽  
Wendell Holswade
Keyword(s):  
Detection System ◽  
Residue Analysis ◽  
Detection Technique ◽  
General Level ◽  
Chlorinated Pesticides ◽  
Efficient Operation ◽  
Column Temperature ◽  
Relative Retention ◽  
Minimum Number ◽  
Multiple Detection

Abstract Conditions are given for the most efficient operation of the microcoulometric gas chromatograph as a multiple detection technique for residues of chlorinated pesticides. Conditions are as follows: Column, aluminum, 6’ long by 4.5 mm i.d., packed with 10% DC 200 silicone fluid (12,500 est) on 80/90 mesh Anakrom ABS (conditioned 1—5 days at 250°C), 210°C column temperature, and 120 ml/min. N2 flow. Chromatography of certain pesticides is improved by injection of cleaned up crop extracts. Columns with a minimum number of bends are superior to coiled columns. Chromatography is not improved by using glass columns. Relative retention times and instrument sensitivity are tabulated for 87 chlorinated and 26 thio pesticide chemicals. Theoretical chloride recoveries are given for 14 compounds and sulfur recoveries for 3 compounds. Theoretical recoveries indicate that the MCGC system is linear for a particular pesticide when it is present above some minimum quantity. Sample cleanup is essential for consistently accurate and reproducible results. The general level of "maximum sensitivity" of this multiple detection technique is approximately 0.01 ppm. The specificity of the detection system (for CI-, Br-, I- or sulfur) is the instrument's greatest virtue.

A Gas Chromatographic Column for Pesticide Residue Analysis: Retention Times and Response Data

1966 ◽  
Vol 49 (2) ◽  
pp. 374-385
Author(s):  
Jerry A Burke ◽  
Wendell Holswade
Keyword(s):  
Liquid Phase ◽  
Flow Rate ◽  
Residue Analysis ◽  
Operating Conditions ◽  
The Other ◽  
Pesticide Residue Analysis ◽  
Column Temperature ◽  
Response Data ◽  
Relative Retention ◽  
Injection Temperature

Abstract DC-200 and QF-1 have been combined as the liquid phase in a GLC column to give a different elution of pesticides from the nonpolar methyl silicones now in wide use. The column packing consists of intimately mixed, equal portions of previously coated 80/100 mesh Gas Chrom Q: one portion with 15% QF-1 and the other with 10% DC-200. Operating conditions for a 6 ft × 4 mm i.d. column are as follows: column temperature, 200°C; injection temperature, 225°C; and flow rate, 120 ml N2/min. Relative retention times and response data for electron capture and microcoulometric GLC systems are tabulated for over 85 pesticide chemicals.

Investigations of Electron Capture Gas Chromatography for the Analysis of Multiple Chlorinated Pesticide Residues in Vegetables

1964 ◽  
Vol 47 (2) ◽  
pp. 326-342
Author(s):  
Jerry Burke ◽  
Laura Giuffrida
Keyword(s):  
Electron Capture ◽  
Gas Chromatograph ◽  
Green Beans ◽  
Chlorinated Pesticides ◽  
Reagent Blank ◽  
Efficient Operation ◽  
Average Recovery ◽  
Relative Retention ◽  
Automatic Integration ◽  
Peak Areas

Abstract Conditions have been experimentally worked out for most efficient operation of the electron capture gas chromatograph, with the objective of routinely determining 0.01 ppm of residues of chlorinated pesticides with GLC characteristics like heptachlor epoxide. These conditions are as follows: Column 6' long by 4 mm i.d., packed with 10% DC 200 (12,500 est) on 80/90 mesh Anakrom ABS, conditioned 1—5 days at 250°C; 200°C column and detector temperature; 120 ml/min. flow N2. Conditioning of the column by chromatographing cleaned up crop extracts through it improves results with certain pesticides. Relative retention times are tabulated for 65 compounds. Sample cleanup is essential for consistently accurate results; the Mills-Onley-Gaither method was used in our work. To insure a zero reagent blank, solvents must be distilled, all glassware rinsed with solvent, blender and funnel carefully cleaned, and no polyethylene containers used to store solvents. Quantitative analysis is made by comparing peak areas of sample and standard, preferably by automatic integration. Experimental work on crop samples was done with corn, spinach, carrots, green beans, potatoes, broccoli, peas, lettuce, radishes, green onions, kale, and cabbage. Over-all average recovery was 84% for seven common pesticides added to 100 g samples of broccoli at 0.001-0.1 ppm.

Determination of Potential Genotoxic Impurity, 5-Amino-2-Chloropyridine, in Active Pharmaceutical Ingredient Using the HPLC-UV System

2020 ◽  
Author(s):  
Murat Soyseven ◽  
Rüstem Keçili ◽  
Hassan Y Aboul-Enein ◽  
Göksel Arli
Keyword(s):  
Analytical Method ◽  
High Performance ◽  
Orthophosphoric Acid ◽  
Limit Of Detection ◽  
Detection System ◽  
Active Pharmaceutical Ingredient ◽  
Limit Of Quantification ◽  
Column Temperature ◽  
Water Ph

Abstract A novel analytical method, based on high-performance liquid chromatography with a UV (HPLC-UV) detection system for the sensitive detection of a genotoxic impurity (GTI) 5-amino-2-chloropyridine (5A2Cl) in a model active pharmaceutical ingredient (API) tenoxicam (TNX), has been developed and validated. The HPLC-UV method was used for the determination of GTI 5A2Cl in API TNX. The compounds were separated using a mobile phase composed of water (pH 3 adjusted with orthophosphoric acid): MeOH, (50:50: v/v) on a C18 column (150 × 4.6 mm i.d., 2.7 μm) at a flow rate of 0.7 mL min−1. Detection was carried out in the 254 nm wavelength. Column temperature was maintained at 40°C during the analyses and 10 μL volume was injected into the HPLC-UV system. The method was validated in the range of 1–40 μg mL−1. The obtained calibration curves for the GTI compound was found linear with equation, y = 40766x − 1125,6 (R2 = 0.999). The developed analytical method toward the target compounds was accurate, and the achieved limit of detection and limit of quantification values for the target compound 5A2Cl were 0.015 and 0.048 μg mL−1, respectively. The recovery values were calculated and found to be between 98.80 and 100.03%. The developed RP-HPLC-UV analytical method in this research is accurate, precise, rapid, simple and appropriate for the sensitive analysis of target GTI 5A2Cl in model API TNX.

Comparison of Some Cleanup Columns for Residue Analysis of Chlorinated and Phosphorus-Containing Pesticides

1971 ◽  
Vol 54 (1) ◽  
pp. 147-149
Author(s):  
B Versino ◽  
M-TH van der Venne ◽  
H Vissers
Keyword(s):  
Column Chromatography ◽  
Residue Analysis ◽  
Chlorinated Pesticides ◽  
Adsorption Column ◽  
Phosphorus Containing ◽  
Better Than

Abstract A comparison is presented of 8 of the most widely used cleanup methods based on adsorption column chromatography for chlorinated and phosphorus-containing compounds and their metabolites. For chlorinated pesticides, all methods show equivalent efficiency and recovery. For phosphorus-containing compounds and metabolites, methods employing columns filled with adsorbent mixtures work better than “all-Florisii” columns.

Programmed Temperature Gas Chromatography (PTGC) and Microcoulometric Detection of Chlorinated Insecticides

1963 ◽  
Vol 46 (2) ◽  
pp. 198-204
Author(s):  
Jerry Burke
Keyword(s):  
Gas Chromatography ◽  
Detection System ◽  
Operating Parameters ◽  
Gas Chromatograph ◽  
Relative Retention ◽  
Wide Range ◽  
Isothermal Gas

Abstract Commercial models of a programmed temperature gas chromatograph and microcoulometric detection system were combined to study programmed temperature gas chromatography (PTGC) of chlorinated insecticides. PTGC permitted the analysis of samples containing materials whose volatilities cover a wide range. PTGC produced better chromatograms and was faster than isothermal gas chromatography. PTGC did not achieve separations which were not possible by isothermal gas chromatography. Operating parameters for a PTGC residue screening operation were determined. Relative retention times at these conditions are given for 22 pesticides. Other advantages of the PTGC instrumentation are noted.

Establishment of Residue Analysis of Propanil (Dichloropropionanilide), Linuron and Diphenamide in Agricultural Commodities

1985 ◽  
Vol 48 (4) ◽  
pp. 320-324 ◽  
Author(s):  
YOSHIO ITO ◽  
HIDEYO SUZUKI ◽  
SHUNJIRO OGAWA ◽  
MASAHIRO IWAIDA
Keyword(s):  
Detection System ◽  
Residue Analysis ◽  
Brown Rice ◽  
Sodium Hydride ◽  
Gas Chromatograph ◽  
Florisil Column ◽  
Florisil Column Chromatography ◽  
Additional Level ◽  
Ppm Level

A method for simultaneous determination of residues of three herbicides containing nitrogen, propanil (3′,4′-dichloropropionanilide), linuron and diphenamide, in agricultural commodites was established. The herbicides were extracted by acetone from samples, transferred into dichloromethane, then the dichloromethane extract was dried. The residue was dissolved in n-hexane, and purified from oily contaminants by partition with acetonitrile. The acetonitrile extract was further purified by Florisil column chromatography with dichloromethane. Diphenamide was determined directly by use of gas chromatograph equipped with a flame-thermoionic detection system (FTDGC). DCPA and linuron were derivatized into their N-monomethyl derivatives by a strong methylation method by use of sodium hydride and methyl iodide in a mixture of dimethyl sulfoxide and benzene, and then subjected to determination by FTD-GC. Recoveries of the three herbicides from brown rice, barley, corn, potato, carrot and onion were not less than 80% at the additional level of 1.0 ppm, while not less than 70% at 0.1 ppm level, respectively.

Determination of Dithiocarbamate and Its Breakdown Product Ethylenethiourea in Fruits and Vegetables

1995 ◽  
Vol 78 (5) ◽  
pp. 1238-1243 ◽  
Author(s):  
Nazir Ahmad ◽  
Lin Guo ◽  
Peter Mandarakas ◽  
Sevieone Appleby
Keyword(s):  
Carbon Disulfide ◽  
Fruits And Vegetables ◽  
Residue Analysis ◽  
Headspace Analysis ◽  
Internal Standard ◽  
Detector Response ◽  
Breakdown Product ◽  
Uv Detector ◽  
Column Temperature ◽  
Sample Extract

Abstract Improved methods for determination in fruits and vegetables of ethylene bisdithiocarbamate (EBDC) residues as carbon disulfide by gas–liquid chromatographic headspace analysis and of othylenethio-urea (ETU) residues by liquid chromatography (LC) are described. Improvements to the EBDC procedure include increased sensitivity by use of 140 mL crimp seal samples bottles fitted with silicone seals, which are leak-proof and reduce headspace volume; use of a Porapak column, which allows use of higher column temperature for better residue separation; and inclusion of thiopheno as an internal standard for bettor quality control. The relationship between the logarithm of the response of carbon disulfide divided by the thiophene response versus concentration of carbon disulfide is expressed by the regression equation Y = 1.011 X + 0.008, with a correlation coefficient r2 = 0.993. Mean recoveries from 8 commodities spiked with mancozcb at 1 and 3 mg/kg, equivalent to 0.473 and 1.419 mg/kg carbon disulfide, are 94.2 ±10 and 98.3 ± 13%, respectively. The Improved LC procedure for ETU residue analysis requires minimal cleanup of sample extract, no derivatization prior to injection, and no specialized LC detectors for quantitation. The UV detector response at 240 nm Is linearly related to ETU concentration [Y = (3.18X – 0.778) × 1000. r2 = 0.997]. Moan ETU recovery from 5 commodities spiked at 0.2 to 5 mg/kg is 93.9 ± 6%. ETU residues of 0.02 to 0.25 μg/g were detected in macerated samples of fruits and vegetables spiked with man-cozeb at 5 μg/g and incubated at room temperature for 3 days. The improved procedures were used to analyze EBDC and ETU residues in fruits and vegetables sampled at a wholesale Sydney produce market. Approximately 30% of samples tested contained EBDC residues, whereas ETU residues in the same samples were below the detection limit of the analytical method (<0.02 mg/kg).

Multiple Harmonic Electron Paramagnetic Resonance Spectroscopy by Simultaneous Detection

1989 ◽  
Vol 43 (6) ◽  
pp. 1021-1026 ◽  
Author(s):  
Yuhei Shimoyama ◽  
Hiroshi Watari
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Second Harmonic ◽  
Detection System ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Simultaneous Detection ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Electron Spin Relaxation ◽  
Multiple Detection ◽  
Electron Paramagnetic

A simultaneous measurement method was developed to permit the multiple detection of the first- and second-order harmonic displays of electron paramagnetic resonance (EPR) spectra. Application of integration and differentiation of amplitude and phase simultaneously, i.e., vector operations on the various displays, enables identification of signals expressed by the various harmonics. By using simultaneous detection, we found for the first time that signals indicated by the different displays are not always identical. The transformation from the first to the second harmonic displays (or vice versa) by vector operations indicated that the displays were not interchangeable when nonlinear response was involved. Simultaneous detection proved to be useful for measurements of the electron spin relaxation where multiple signals coexist. The present detection system provides a means for multivector EPR spectroscopy.

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