Fast Cleanup of Difficult Substrates for Determination of Fenitrothion and Some Derivatives

1981 ◽  
Vol 64 (6) ◽  
pp. 1470-1473
Author(s):  
Patrick Haché ◽  
René Marquette ◽  
Gilles Volpé ◽  
Victorin N Mallet
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Parent Compound ◽  
Chicken Liver ◽  
Gas Liquid Chromatography ◽  
Fast Recovery ◽  
Simple Method ◽  
Flame Photometric Detector ◽  
Derivatives Of

Abstract A simple method is described for the fast recovery of fenitrothion, an organophosphorus insecticide, from soil, chicken liver, urine, clams, and pine needles. The substrate is homogenized with acetonitrile or methanol, diluted with water, and passed through a column containing Amberlite XAD-7. Fenitrothion is recovered quantitatively by eluting with 4 portions of 25 mL ethyl acetate. After evaporation, the compound is determined quantitatively by gas-liquid chromatography with a flame photometric detector. The procedure is also suitable for some derivatives of fenitrothion, namely, fenitrooxon and S-methylfenitrothion. As low as 0.05 ppm of the parent compound may be determined.

Rapid Gas-Liquid Chromatographic Method for Determining Residues of Ethephon (2-Chloroethyl Phosphonic Acid) in Tomatoes

1976 ◽  
Vol 59 (5) ◽  
pp. 1185-1187
Author(s):  
George F Ernst ◽  
Marcia J P T Anderegg
Keyword(s):  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Phosphonic Acid ◽  
Growth Regulator ◽  
Chromatographic Method ◽  
Gas Liquid Chromatography ◽  
Flame Photometric Detector ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A rapid method is described for the determination of the growth regulator ethephon (2-chloroethyl phosphonic acid) in tomatoes. Samples are extracted with ethyl acetate. The extract is methylated, decolorized with carbon, and analyzed by gas-liquid chromatography on a column packed with 15% QF-1/10% DC-200 on Chromosorb W (HP). A flame photometric detector is used. Recoveries from tomatoes fortified with 0.1–11.0 ppm ethephon were 78—98%. The sensitivity of this method is about 0.1 ppm.

Micro-Determination of p-Hydroxybenzoic Esters in Pharmaceuticals and Cosmetics

1977 ◽  
Vol 60 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Emil Weisenberg ◽  
Baruch Gershon ◽  
Judith Schoenberg
Keyword(s):  
Liquid Chromatography ◽  
Phosphate Ester ◽  
Specific Method ◽  
Gas Liquid Chromatography ◽  
Direct Extraction ◽  
Flame Photometric Detector ◽  
Phenol Derivatives ◽  
Margin Of Error ◽  
Diethyl Phosphate

Abstract A rapid and specific method is described for the determination of microamounts of methyl, propyl, and butyl p-hydroxybenzoic esters (parabens) in pharmaceuticals and cosmetics. The method involves the direct extraction of parabens into benzene or chloroform followed by derivatization with phosphorochloridate. The diethyl phosphate ester derivatives are cleaned up on a Florisil minicolumn and finally measured by gas-liquid chromatography on 5% OV-210 on Gas-Chrom Q. A flame photometric detector or a KCl thermionic detector may be used. The concentration response was linear up to 40 ng parabens. The reproducibility and margin of error were tested with fortified samples. This method may be applied to the estimation of other phenol derivatives.

Determination of unconjugated 3-methoxy-4-hydroxyphenylglycol by liquid chromatography for monitoring inhibition of monoamine oxidase activity in plasma.

1987 ◽  
Vol 33 (11) ◽  
pp. 2078-2080 ◽  
Author(s):  
R N Gupta ◽  
M Steiner ◽  
M Lew
Keyword(s):  
Liquid Chromatography ◽  
Monoamine Oxidase ◽  
Ethyl Acetate ◽  
Aqueous Phase ◽  
Oxidase Activity ◽  
Back Extraction ◽  
Monoamine Oxidase Activity ◽  
Simple Method ◽  
Extraction Recovery

Abstract We describe a simple method for extracting 3-methoxy-4-hydroxyphenylglycol (MHPG) from plasma. The sample is applied to a 1-mL "Extrelut" column (EM Industries) and eluted 15 min later with ethyl acetate. After mixing the eluate with pentane and back-extraction into water, we inject 25 or 50 microL of the aqueous phase onto a Beckman 15 cm x 4.6 mm (i.d.) column packed with 5-micron ODS particles (Beckman). Peaks are detected with a coulometric detector. The resulting chromatogram is clean, with few extraneous peaks. The extraction recovery of MHPG is 55-60%, which allows for detection of as little as 0.2 microgram of the analyte per liter. The decrease in the concentration of MHPG in plasma of patients treated with phenelzine agrees with the decrease in monoamine oxidase activity in platelets of these patients.

Collaborative Study of the Quantitative Determination of Fusel Oil and Ethyl Acetate by Gas-Liquid Chromatography

1968 ◽  
Vol 51 (4) ◽  
pp. 915-921
Author(s):  
Richard L Brunelle
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Ethyl Acetate ◽  
Simultaneous Determination ◽  
Collaborative Study ◽  
Gas Liquid Chromatography ◽  
Fusel Oil ◽  
Preliminary Work ◽  
Standard Deviations

Abstract Thirteen chemists representing twelve laboratories participated in a collaborative study for the quantitative determination of ethyl acetate and fusel oil by GLC. The results on four samples containing various amounts of ethyl acetate and fusel oil were compared with the official AOAC procedures. For all samples, the standard deviations were lower with GLC. Collaborators preferred the GLC procedure because the simultaneous determination of ethyl acetate and n-propyl, iso-butyl, and isoamyl alcohols is possible. Results from preliminary work performed on the quantitative determination of acetaldehyde by GLC were encouraging. It is recommended that the proposed GLC procedure for the quantitative determination of ethyl acetate and fusel oil be adopted as official, first action, and that work be continvied on the determination of acetaldehyde by GLC.

Effects of Oil Contamination on Cotton Quality: Methods of Analysis and Characterization of Contaminants

1977 ◽  
Vol 47 (4) ◽  
pp. 271-276 ◽  
Author(s):  
Henry H. Perkins ◽  
Charles K. Bragg
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Oil Contamination ◽  
Gas Liquid Chromatography ◽  
Infrared Spectrophotometry ◽  
Simple Method ◽  
Yarn Strength ◽  
Problem Severity

Oil contamination of cotton is a recurring problem that adversely affects cotton quality. Processing problems occur in carding through spinning, and both yarn strength and appearance are lowered. Problem severity increases as the level of contamination increases. A simple method is described for quantitative determination of contamination. Contaminants are characterized and differentiated from each other and from the natural constituents of cotton by use of infrared spectrophotometry and gas-liquid chromatography.

Modified Storherr Method for Determination of Organophosphorus Pesticides in Nonfatty Food Total Diet Composites

1981 ◽  
Vol 64 (3) ◽  
pp. 714-719
Author(s):  
Louis J Carson
Keyword(s):  
Liquid Chromatography ◽  
Pesticide Residues ◽  
Organophosphorus Pesticides ◽  
Organophosphorus Pesticide ◽  
Gas Liquid Chromatography ◽  
Flame Photometric Detector ◽  
Limit Of Quantitation ◽  
Total Diet ◽  
Residue Levels

Abstract The method of Storherr et al. for organophosphorus pesticide residues in nonfatty foods has been modified to permit its use in analyzing the composites of nonfatty foods in the Food and Drug Administration Total Diet Program. Modifications were designed to permit the examination by gas-liquid chromatography (GLC) of the larger weight (100 mg) of sample equivalent required by the Total Diet program. To achieve a limit of quantitation of 2 ppb parathion, the organophosphorus pesticides are determined by GLC equipped with flame photometric detector (P-mode) and/or KCl thermionic detector. Recovery data, ranging from 70 to 133%, are presented for fortification (2-10 ppb) of organophosphorus pesticides in 7 nonfatty food Total Diet composites. The modified Storherr method was successfully tested in an intralaboratory method trial of 2 Total Diet composites (potatoes and legumes) fortified at 5-13 ppb with malathion, parathion, paraoxon, and monocrotophos. In addition, the modified Storherr method was compared to existing FDA Total Diet methodology for the determination of incurred organophosphorus residues. Residue levels found by both methods were similar for malathion (30 ppb), parathion (7 ppb), and diazinon (1 ppb), but only the modified Storherr method was capable of determining about 10 ppb dimethoate and phorate in the cereals and grains composite.

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