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Biomedical subjects

M C Bowman

Publications and source records attributed to M C Bowman.

At least 19 recordsLinked to original sources
PubMed1979

Trenbolone acetate and trenbolone: trace analysis in animal chow, wastewater and human urine by high pressure liquid chromatography and electron capture gas chromatography.

Analytical methodology is described for determining residues of the synthetic anabolic steroid trenbolone acetate (TBA) and its hydrolysis product trenbolone (TBOH) in admixture in animal chow, human urine, and wastewater. Benzene extracts of the substrates are subjected to liquid-liquid partitioning, further cleanup on a column of silica gel, and direct analysis by high pressure liquid chromotography or derivatization with pentafluoropropionic anhydride and analysis by electron capture gas chromatography. Satisfactory recoveries were obtained with both compounds from all three substrates. Residue levels of TBA and TBOH as low as 0.32 and 0.04 ppm, respectively, could be detected in chow; about 0.6 ppb of each compound could be detected in urine and wastewater. Thin layer chromatographic behavior of the two compounds in 7 solvent systems and other ancillary analytical data are also presented.

Acetates↗
PubMed1979

Control of test substances.

The efficient control of chemicals during a nonclinical laboratory study is of the utmost importance from three main points of view: (1) integrity of the experiment, (2) safety of personnel, and (3) protection of the environment. While the general principles involved in chemical control may be set forth in formal GLPs, detailed problems concerning individual test substances can only be resolved by utilizing the competency and judgment of a researcher who possesses adequate analytical chemical methods. Integrity of an experiment requires knowledge of the identity, purity, and stability of the test substance, as well as its proper handling and storage and a knowledge of its chemical properties. Assurance of homogeneity, stability, and proper concentration of the chemical in the dosage form is also of primary importance. The development and use of adequate analytical chemical procedures for determining the test agent in human samples, air, clothing, and on work surfaces is necessary for the initiation of surveillance procedures to assure safety of personnel from exposure to the test substances. The environment must be protected from hazardous test substances by using adequate disposal techniques for the chemical and all contaminated materials. This usually involves development of wastewater cleanup systems and continuous monitoring of the effluent to prevent discharge of hazardous substances. Incineration is the most useful method for disposal of solids and highly contaminated liquids. Work from our laboratory, done during the past 5 years, provides an illustration of the important principles, problems, and pitfalls encountered in chemical control.

Environmental Exposure↗
PubMed1978

Carcinogens and analogs: trace analysis of thirteen compounds in admixture in wastewater and human urine.

A gas chromatographic method is described for determining traces of 13 carcinogens and related compounds (aromatic amines and estrogens) in admixture in wastewater and human urine. This method was developed for use in toxicological research for monitoring the safe disposal of wastewater and to signal any accidental exposure of personnel to hazardous test substances. Salient elements of the procedure are: extraction of phenolic and neutral residues from the acidified sample, liquid--liquid partitioning cleanup and separation of neutral from phenolic residues at pH 14 and 10.2, acid hydrolysis of the neutral component, subsequent alkalinization of the sample and extraction of the basic residues as the free amines, conversion of all residues to the corresponding pentafluoropropionyl (PFP) derivatives and quantification by electron-capture gas chromatography. Residues were detectable in wastewater and urine at the 0.1 and 1 ppb levels, respectively. Additional information is provided concerning partition values for all PFP derivatives in five solvent systems, structure verification of the derivatives by mass spectrometry and the adaption of this method to the monitoring of surfaces and air in potentially contaminated work areas.

Amines↗
PubMed1978

Determination of sodium phenobarbital in animal chow by high-pressure liquid chromatography.

An analytical procedure is described for determining residues of sodium phenobarbital in animal chow at levels as low as 0.14 ppm. The methanol extract is subjected to a liquid-liquid cleanup at pH 13 and 1, further cleaned up on a silica gel column and assayed by high-pressure liquid chromatography by using an ultraviolet absorption detector at 210 nm. Data concerning extraction efficiency, partition values and stability of the chemical in animal chow are also presented.

Animal Feed↗
PubMed1978

High pressure liquid chromatographic determination of rotenone and degradation products in animal chow and tissues.

An analytical procedure is described for determining residues of rotenone, rotenolone, dehydrotenone, and rotenone in admixture in animal chow and tissues. The methanol or ethyl ether extracts from samples of chow and tissues, respectively, are subjected to a liquid-liquid partitioning cleanup with hexane-acetonitrile, further cleanup on a column of silica gel, and subsequent analysis by high pressure liquid chromatography using an ultraviolet absorption detector set at 295 nm. Animal chow, mouse fetuses, and gastrointestinal tracts spiked with 0.5 ppm of each compound in admixture yielded average recoveries of 92, 51, and 79%, respectively; minimum quantities of the 4 compounds detectable in the 3 substrates averaged 0.12, 0.04, ajd 0.14 ppm, respectively. Stability studies indicate that rotenone reacts with animal chow with a half-life of 7--8 days and is photodegraded in incandescent light with a half-life of 0.65 day. No transplacental transfer of rotenone or its products was observed in fetuses from mice receiving 7 consecutive daily doses of rotenone at levels up to 25 mg/kg.

Animal Feed↗
PubMed1977

Trace analysis of estradiol in animal chow by electron-capture gas chromatography.

A gas chromatographic method is described for trace analysis of the natural steroidal hormone estradiol in animal chow at levels as low as 3 ppb. Salient elements of the method include extraction of the estradiol with methanol, an initial clean-up on a column of Sepadex LH-20, liquid-liquid partitioning at pH 14 and 10.2, additional cleanup on a slilica gel column, conversion of the estradiol to the pentafluoropropionly (PFP) derivative and analysis by electron-capture gas chromatography on a column of OV-25. Samples containing less than ppb of estradiol are subjected to further clean-up on silica gel after derivatization and prior to analysis.

Animal Feed↗
PubMed1977

Trace analysis of diethylstilbestrol [DES] in animal chow by parallel high-speed liquid chromatography, electron-capture gas chromatography, and radioassays.

An analytical method is described for determining residues of the synthetic estrogen diethylstilbestrol (DES) in animal chow at levels as low as 1 ppb. A methanol extract of the chow is subjected to a 3-step cleanup procedure including a Sephadex LH-20 column, liquid-liquid partitioning at pH 14 and 10.2, and a silica gel column. Residues of DES in the cleaned-up extract are analyzed directly by high-speed liquid chromatography or derivatized to pentafluoropropionyl-DES and assayed by electron-capture gas chromatography. Tests with 14C-DES were used to develop and validate the procedure. Ancillary data concerning extraction efficiencies of various solvents, comparisons of various derivatizing reagents, rates of trans-cis isomerization in two solvents, P-values of DES in various solvent-systems and thin-layer chromatographic behavior i

Animal Feed↗
PubMed1977

Trace analysis of zearalenone and/or zearalanol in animal chow by high pressure liquid chromatography and gas-liquid chromatography.

An analytical method is described for determining residues of the estrogens zearalenone and/or zearalanol in animal chow at levels as low as 10 ppb. The chow is extracted with methanol and cleaned up by a 3-step procedure employing a Sephadex LH-20 column, liquid-liquid partitioning at pH 13 and 8.3, and a silica gel column. Residues of the 2 compounds, separated on silica gel, are assayed by using high pressure liquid chromatography with ultraviolet detection. Additional data are also included concerning p-values of the compounds in several solvent systems, Rf values from thin layer chromatography with 9 solvent systems, solubilities in 3 solvents, and a procedure for preparing their pentafluoropropionyl derivatives for analysis by electron capture gas-liquid chromatography.

Animal Feed↗
PubMed1976

Trace analysis of 2,4,5-trichlorophenoxyacetic acid, its glycineamide, and their alkaline hydrolyzable conjugates in mouse blood, urine, and feces.

Chemical methods were developed for the trace analysis of the herbicide 2,4,5-trichlorophenoxyacetic acid, its glycineamide, and their alkaline hydrolyzable conjugates in mouse blood, urine, and feces. The salient elements of the methods are extraction of the free acids with benzene, methylation, cleanup on a silica gel column, and quantification via electron-capture GLC. Any unextracted conjugates remaining in the substrates are then subjected to alklaline hydrolysis, and the liberated 2,4,5-trichlorophenoxyacetic acid is assayed. Data are presented concerning recoveries of the compounds from the three spiked substrates. The utility of the procedures is illustrated by a preliminary pharmacolinetic study employing parallel electron-capture GLC and radioassays of the three substrates from mice injected with a single intravenous dose of 14C-2,4,5-trichlorophenoxyacetic acid. GLC characteristics and partition values of the the compounds and hydrolysis of the glycineamide under various conditions also are discussed.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1976

Benzidine and congeners: analytical chemical properties and trace analysis in five substances.

Spectrophotofluorimetric (SPF) methods are described for the trace analysis of benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, and their dihydrochloride salts in microbiological growth media, waste water, potable water, human urine, and rat blood. The salient elements of the methods for these known or suspected carcinogens are: extraction of the residues as the free amine with benzene, rapid cleanup on an alumina column, and quantification of the free amine in methanol via SPF. Potable water solutions of the salts are diluted with buffer (pH-4) and quantified directly by SPF. Ancillary analytical information concerning the solubility and stability of these compounds in water, p-values, gas chromatographic analysis of the free amines, and thin layer chromatographic data in ten solvent systems are also presented.

Animals↗
PubMed1976

4-aminobiphenyl, 2-naphthylamine, and analogs: analytical properties and trace analysis in five substrates.

Methods for monitoring trace levels of 4-aminobiphenyl, 2-naphthylamine, and their hydrochloride salts in waste water, microbiological growth media, potable water, human urine, and mouse blood utilizing spectrophotofluorometry (SPF) are described. The salient elements of the methods are extraction of the residues as the free amine with benzene, rapid cleanup on an alumina column, and quantification of the free amine in methanol via SPF. Potable water solutions of the salts are diluted with 0.01 N aqueous HCL and quantified directly by SPF. Ancillary analytical information concerning gas chromatography of the free amines, partitioning properties of the compounds between solvent pairs, their solubility and stability in water, and thin-layer chromatographic data is presented. The compositions of various admixtures of 1- and 2-naphthylamine or their salts were determined by using SPF with calculations based on simultaneous equations.

2-Naphthylamine↗
PubMed1975

Removal of trace levels of 2-acetylaminofluorene (2-AAF) from wastewater.

An adsorption system is described for the removal of part per billion levels of the chemical carcinogen, 2-acetylaminofluorene (2-AAF), from industrial wastewater. The system consists primarily of filters and activated carbon and non-ionic polymeric adsorbents arranged in tandem. It is highly efficient, operates at low cost, and requires minimal attention. The chemical monitoring of the raw and/or cleaned-up wastewater is based on a highly sensitive and specific spectrophotofluorometric method that allows acceptance or rejection of samples at the 0.2 part per billion level. The system is presented as a model for evaluating the removal of traces of organic chemicals from wastewater prior to recycling or discharging it into the environment. Results of laboratory evaluations of several other approaches to the purification of 2-AAF-containing wastewater are also presented.

2-Acetylaminofluorene↗
PubMed1975

Analysis of insect chemosterilants.

Background information concerning the concept of insect chemosterilization and analytical methods for determining trace levels of 19 P- and/or S- containing chemicals of current interest are presented. GC retention times of the compounds on 6 different columns and their p-values in 11 solvent systems are tabulated. The utility of the flame photometric detector for determining subnanogram levels of the sterilants in biological substrates is illustrated.

Animals↗