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

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.

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

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/64.6.1470 ◽

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.

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Simultaneous Measurement of Diphenylhydantoin and Primidone in Serum by Gas—Liquid Chromatography

Clinical Chemistry ◽

10.1093/clinchem/16.2.107 ◽

1970 ◽

Vol 16 (2) ◽

pp. 107-110 ◽

Cited By ~ 19

Author(s):

M A Evenson ◽

P Jones ◽

B Darcey

Keyword(s):

Liquid Chromatography ◽

Clinical Chemistry ◽

Chemistry Laboratory ◽

Specific Method ◽

Gas Liquid Chromatography ◽

Serum Samples ◽

Large Numbers ◽

Clinical Chemistry Laboratory ◽

Isothermal Gas

Abstract The need for simultaneous determination of the concentration of diphenylhydantoin (Dilantin) and primidone (Mysoline) in serum is frequently expressed to the clinical chemistry laboratory. Isothermal gas-liquid chromatography (GLC) has been used to develop a rapid, specific method. The method involves a single extraction and no derivative formation. The procedure is simple enough to be used with large numbers of samples. Detection limits for the method are 0.3 µg diphenylhydantoin per ml and 0.1 µg primidone per ml. The mean precision of the method is 6.2% and 4.8%, expressed as the coefficient of variation, for diphenylhydantoin and primidone, respectively. Barbiturates and glutethimide added to serum samples did not interfere with the analysis. The method has been used for more than 500 patients without interferences from metabolites, and meets all criteria for routine and emergency use.

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Quantitative Determination of Benzaldehyde in Flavors by Gas-Liquid Chromatography

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/46.6.950 ◽

1963 ◽

Vol 46 (6) ◽

pp. 950-951

Author(s):

Richard L Brunelle ◽

Glenn E Martin

Keyword(s):

Liquid Chromatography ◽

Liquid Phase ◽

Benzoic Acid ◽

Quantitative Determination ◽

Solid Support ◽

Specific Method ◽

Gas Liquid Chromatography ◽

Ultraviolet Spectrophotometry ◽

Liquid Chromatography Separation

Abstract A rapid and specific method is given for determination of benzaldehyde in the presence of interfering substances by gas-liquid chromatography. Separation is effected on a ¼ column containing 2 5% Apiezon M as the liquid phase on a solid support of Chromoport XXX (60—80 mesh) at isothermal conditions, 100°C. The determination can be performed in the presence of benzoic acid and other interfering substances. Results are compared with those obtained by ultraviolet spectrophotometry on a variety of almond and cherry flavors.

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

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/64.3.714 ◽

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

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/59.5.1185 ◽

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.

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GASCHROMATOGRAPHIC DETERMINATION OF STEROIDS IN THE URINE OF PATIENTS WITH CUSHING'S SYNDROME

Acta Endocrinologica ◽

10.1530/acta.0.0670303 ◽

1971 ◽

Vol 67 (2) ◽

pp. 303-315 ◽

Cited By ~ 14

Author(s):

A. J. Moolenaar ◽

A. P. van Seters

Keyword(s):

Liquid Chromatography ◽

Cushing’S Syndrome ◽

Normal Subjects ◽

Diagnostic Value ◽

Cushing's Syndrome ◽

Gas Liquid Chromatography ◽

Obese Subjects

ABSTRACT The 17-oxosteroids were estimated in the urine of 27 patients with Cushing's syndrome by gas-liquid chromatography (G. L. C.). The values of the various steroid fractions are compared with those of normal subjects, patients with thyrotoxicosis and obese subjects. The effect of the age of the patients on the diagnostic value of the invidual 17-oxosteroids and their ratios is discussed.

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