bluuebunny/crossref_metadata_2025 huggingface dataset:
The Confirmation of Diethylstilbestrol Residues in Beef Liver by Gas Chromatography-Mass Spectrometry
Authors: Day Edgar W , Vanatta Lynn E , Sieck Robert F
Published: February 2020

A confirmatory test for the presence of the growth-promoting hormone, diethylstilbestrol (DES), in beef liver is described. Samples are subjected to a published electron capture gas chromatographic method that involves the formation and measurement of the bis-dichloroacetyl derivative of DES. The presence of the derivative is then confirmed by gas chromatography-mass spectrometry, using a repetitive scanning technique to maximize response. The isotope pattern of the tetrachlorinated molecular ion greatly facilitates the confirmation.
Estimation of Glycoalkaloids as Solasodine in Solanum laciniatum
Authors: Karawya Mohamed S , Ghourab Mohamed G , Elrakhawy Faten H
Published: February 2020

Solasodine is isolated from Solatium laciniatum leaves by a rapid, one-step procedure which involves extraction and hydrolysis of the glycoalkaloids. The resulting steroidal aglycone is directly estimated by the formation of a colored complex with bromocresol green. The method is applicable to concentrations of 25–125 µg solasodine/7 ml.
The Analysis of Pharmaceuticals by Combined Gas Chromatography-Mass Spectrometry. I. The Analysis of a Medicated Aerosol Spray
Authors: Sheinin Eric B , Benson Walter R , Brannon Wilson L , Schwartzman George
Published: February 2020

A medicated aerosol product was qualitatively analyzed by combined gas chromatography-mass spectrometry. The data were processed by a minicomputer. Ten of the 11 peaks in the gas chromatogram were identified with the assistance of the National Institutes of Health/Division of Computer Research and Technology/Chemical Information System mass spectral search system. The unidentified peak is probably a member of the terpene class. The aerosol propellants were also partially analyzed by infrared spectrophotometry.
Chemical Ionization Mass Spectrometry of N-Methylcarbamate Insecticides, Some of Their Metabolites, and Related Compounds
Authors: Holmstead Roy L , Casida John E
Published: February 2020

The chemical ionization (CI) mass spectra with methane as the reagent gas are reported for 25 N-methylcarbamato insecticides or related compounds. The [M + 1]+ ions in the CI spectra are larger than the parent ions in the corresponding electron impact (EI) spectra of N-methyl- and N,N-dimethylcarbamates, but the contrary is true with N-hydroxymethylcarbamates. CI but not EI fragmentation of substituted- phenyl N-hydroxymethylcarbamates [ROC(0)NHCH2OH] appears to involve a 4-membered [ROC(0)NHCH2]+ intermediate which rearranges to give a [ROCH2]+ fragment. Other fragmentations unique to the CI spectra are also discussed.
Determination of Coumaphos and Its Oxygen Analog in Eggs by In Situ Fluorometry
Authors: Zakrevsky Jean-Guy , Mallet Victorin N
Published: February 2020

A method is reported for the simultaneous determination of coumaphos (O,0-diethyI 0-(3-chloro-4-methyl-2-oxo-2H-l-benzopyran-7-yl) phosphorothioate) and its oxygen analog, Coroxon, in eggs in the ppb range. The residues are extracted with acetone and chloroform. The extract is purified by liquid-liquid partition followed by column chromatography and then by 2-dimensional thin layer chromatography. The fluorescence is measured directly on the chromatogram.
Gas-Liquid Chromatographic Method for Determining Ethylenethiourea in Plants
Authors: Nash Ralph G
Published: February 2020

An additional gas-liquid chromatographic method has been developed for determining ethylenethiourea (ETU) in plants. Two ETU derivatives, 2-(o-chlorobenzy Ithio)-1-(pentafluorobenzoyl)-2-imidazoline and 2-(benzylthio)-1-(pentafluorobenzoyl)-2-imidazoline, can be prepared from the same extract, which allows confirmation of the presence and quantity of ETU at >5 ppb. No degradation of the parent fungicides to ETU during benzylation or ochlorobenzylation was observed.
Collaborative Study of the Milko-Tester Method for Measuring Fat in Homogenized and Unhomogenized Milk
Authors: Shipe W Frank , Senyk Gary F
Published: February 2020

The Mark III Industrial Model Milko-tester was evaluated to determine its reliability for testing both unhomogenized and homogenized milk samples. Six laboratories participated in 2 trials. In the first trial, the range among laboratories for homogenized milk was 0.29% and unhomogenized milk 0.34%. This variation was apparently due to inaccurate calibrations. In the second trial, 2 calibration standards were used for each type of milk and the range was reduced to 0.04% for homogenized milk and 0.05% for unhomogenized milk. The standard deviations for unhomogenized and homogenized milk were 0.008 and 0.010 for trial 1 and 0.005 and 0.005 for trial 2, respectively. The official first action automated method I for the determination of fat in raw, unhomogenized milk has been expanded to include the determination of fat in homogenized milk by the use of the Mark III Industrial Model Milko-tester.
Determination of Benzaldehyde in Wines and Amyl Acetate and Isoamyl Acetate in Liqueurs by Gas-Liquid Chromatography and Confirmation by Mass Spectroscopy
Authors: Martin Glenn E , Buscemi Peter C , Butts Boyd B
Published: February 2020

Liquid-liquid extraction was carried out prior to gas-liquid chromatographic (GLC) determination of amyl and isoamyl acetate in alcoholic beverages. The concentrations of amyl acetate and isoamyl acetate ranged from 4 to 29 and 2.5 to 322 ppm, respectively. Recovery studies for isoamyl and amyl acetate were carried out; these compounds were recovered at 90 and 92%, respectively. A liquid-liquid extraction also was carried out prior to the GLC determination of benzaldehyde. When chloroform was used in the liquid extraction, the results obtained by the GLC procedure compared favorably in most cases with those obtained by the ultraviolet spectrophotometric procedure. In the GLC method the benzaldehyde varied from 5 to 150 ppm for both imported and natural wines. The compounds in the effluent from the chromatograph, namely, amyl acetate, isoamyl acetate, and benzaldehyde, were confirmed by mass spectroscopy.
Identification of d- or di-∝-Tocopherol in Pharmaceuticals, Food Supplements, or Feed Supplements: A Collaborative Study
Authors: Ames Stanley R , Drury Emma-Jane E
Published: February 2020

A collaborative study was conducted to evaluate a method for identifying d- or dl-∝-tocopherol in pharmaceuticals, food supplements, or feed supplements. The sample is extracted and saponified, the extraneous color is removed by chromatography, and the sample is assayed for vitamin E. Optical rotations are determined before and after formation of the ferricyanide oxidation product. The specific optical rotation of the oxidation product is negligible for the dJ-form and +25.5° for the d-form. Statistical analysis of the data reported by 8 collaborators for the standard d-∝-tocopheryl acetate and for 6 unknown samples indicates a significant interaction between laboratories and samples. The mean coefficients of variation among laboratories for the determinations of the corrected specific optical rotation of the standard and the rotation ratio for the unknown samples containing d-∝-tocopherol were 11.7 and 21.6%, respectively, for all laboratories and 5.8 and 11.8%, respectively, for experienced laboratories. This identification test for vitamin E is acceptable for determining the form of vitamin E as either d or dl, but is not acceptable for accurately determining mixtures of the 2 forms. The method has been adopted as official first action for the identification of d- or dl-∝-tocopherol.
A Specific Method for the Determination of Provitamin A Carotenoids in Orange Juice
Authors: Reeder Samuel K , Park Gary L
Published: February 2020

A method has been developed for rapidly determining the amounts of ∝-carotene, β-carotene, and cryptoxanthin in orange juice. The procedure includes extraction, saponification, and high-speed liquid chromatography. Limits of detection for the 3 carotenoids are 0.04, 0.02, and 0.04 μg/ml, respectively.
Collaborative Study of the Determination of Available Lysine in Proteins and Feeds
Authors: Couch J Russell
Published: February 2020

In the proposed method l-fluoro-2,4-dinitrobenzene (DNFB) is reacted with the free ɛ-amino groups in protein to form DNFB-ɛ-amino lysine which is stable to acid hydrolysis. The sample is acid hydrolyzed and unavailable lysine is determined with an amino acid analyzer; total lysine is determined on the untreated sample. The available lysine, which was bound by DNFB, is determined by difference. The available lysine has been determined in 3 samples of 44% protein soybean meal by 5 collaborators, following the method outlined. The range for available lysine in reference standard 1 was 2.02–2.14%, in reference standard 2, 2.59–2.73% and in reference standard 3, 0.55–0.91%. The method has been adopted as official first action.
Chromatographic Analysis of 4,4’- (Diazoamino) -dibenzenesulfonic Acid in FD&C Yellow No. 6
Authors: Bailey John E , Cox Elizabeth A
Published: February 2020

4,4’- (Diazoamino) -dibenzenesulfonic acid (DAADBSA) has been found in samples of FD&C Yellow No. 6 that were submitted for certification. The material was detected by conventional elution chromatography and highpressure liquid chromatography (HPLC). DAADBSA is synthesized by diazotizing sulfanilic acid. The diazonium compound is then coupled with undiazotized sulfanilic acid in the presence of sodium acetate. A method for the quantitative determination of DAADBSA in FD&C Yellow No. 6 using HPLC is presented. An untested method of correcting for interfering compounds is also described.
A Convenient Thin Layer Chromatographic Cleanup Procedure for Screening Several Mycotoxins in Oils
Authors: Hagan Susie N , Tietjen William H
Published: February 2020

A thin layer chromatographic cleanup development with benzene-hexane (34+1) effectively removed lipids and some contaminants from mixtures of mycotoxins in corn oil, olive oil, peanut oil, soybean oil, and seed extracts. A second development in the same direction as the first, using toluene-ethyl acetate-formic acid ( 6+3+1 ) or benzene-acetic acid (9+l), separated the mycotoxins. Satisfactory separation was achieved for commercial oils spiked with sterigmatocystin, zearalenone, ochratoxins A, B, and C, and anatoxins B1 B2, Gl and G2. This technique permits detection of 5 ppb aflatoxin B1 in corn.
Production of Sterigmatocystin
Authors: Steyn Martin , Rabie Chris J
Published: February 2020

A procedure for the isolation of pure sterigmatocystin is described. It involves cultivation of an appropriate fungus on sterile maize, and extraction and column chromatographic purification of the crude extract. With this method sterigmatocystin may be obtained at a fraction of its commercial cost. Aspergillus versicolor seemed to be the best producer (5–12 g/kg) in 250 ml Erlenmeyer flasks. The yield dropped markedly with increasing flask size.
Laboratory Fabrication of Plastic Slides for Rot Fragment Counting
Authors: Cichowicz Stanley M
Published: February 2020

Slides for rot fragment counting can be easily prepared from plastic plates in the laboratory. The plastic slides are easier to prepare and more economical than the glass slides described in 44.002(t).
Safety Evaluation Concepts
Authors: Golberg Leon
Published: February 2020

The approach to safety evaluation is strongly influenced by the standard of safety to which one aspires. Practical considerations demand that realistic limits be set to the attainable assurances of freedom from anticipated hazard under actual conditions of use of a product. The fact is that, in the interests of consumer health, more can be expected from a flexible, intelligent, and experienced approach to safety evaluation than from efforts at conformity with a set of rigidly standardized requirements that are theoretically all-encompassing. Establishment of safety demands a wide background of information about the properties and likely uses of the product; above all, knowledge of the chemical composition of the product and its impurities, degradation products, and metabolites is essential. Lack of such information is a frequent source of errors in safety evaluation. Based on a secure foundation of this sort, a program of investigations may be designed, aimed at establishing the basic biological properties of the material. Determination of the metabolic dynamics of the principal chemical agent or agents makes possible the emergence of a clear picture of the behavior of the compound(s) in the body and paves the way for more specialized studies of long term toxicity, carcinogenicity, effects on reproduction and teratogenesis, and investigations of multitest mutagenic potential. Emphasis is laid on the problems of interpretation of results in terms of hazard to man and on the crucial contribution that experience of human exposure can make toward assuring safety-inuse. Decisions on acceptable risk are the joint responsibility of many individuals but an essential element in reaching such decisions is contributed by the depth of understanding and broad experience of the toxicologist.
Acute and Prolonged Toxicity Tests
Authors: Loomis Ted A
Published: February 2020

An answer to the question of whether acute and prolonged toxicity tests are good candidates for standardization is developed by reviewing (1) the factors that are presumed to influence the results of these tests and (2) the collaborative studies that have been reported in the literature. In regard to acute toxicity tests it is clear that competent laboratories give due consideration for the control of factors that are known to influence these tests. Also competent laboratories using their own procedures provide reliable results, even though the procedures vary from laboratory to laboratory. In regard to prolonged toxicity tests there are no examples of controlled collaborative investigations which could be used to evaluate interlaboratory variation and its relation to the protocols involved. It is recommended that guidelines rather than rigid protocols would be an appropriate approach for improving the quality and accuracy of these toxicologic tests. Examples of such guidelines are given.
Pathology: Studies of Chronic Toxicity and Carcinogenicity
Authors: Newberne Paul M
Published: February 2020

Safety evaluation of chemicals in use or destined for use by humans is a complex endeavor which requires accurate analytical chemical results, extensive animal studies, and thoughtful interpretation of the data. Especially difficult are attempts to extrapolate the animal data to man. The analytical chemist can base many of his conclusions on data concerning quantity; the toxicologist cannot. The analytical chemist works very hard for an answer, but when he gets it, his task is usually completed. When the toxicologist gets an answer from a given experiment, his problems have just started; he must attempt to interpret the data and, even more difficult, to extrapolate the results of animal data to man. Thus, accurate analysis of chemicals and trace substances in biological tissues form the foundation of the work of the toxicologist. A closer association between analytical chemists and toxicologists should prove beneficial to both and to the progress of science.
Reproduction and Teratogenesis: Current Methods and Suggested Improvements
Authors: Wilson James G
Published: February 2020

The risks to human reproduction, particularly in regard to possible induction of birth defects, from present levels of environmental chemicals are thought to be low but in need of closer scrutiny than is now the case. Methods currently used to estimate the hazards to reproduction of new chemicals and drugs are reviewed and some shortcomings and potential sources of error are noted. Specific suggestions are made for improving existing methodology. In addition to the widely used treatment span encompassing all or most of the period of organogenesis, it is proposed that some exposure periods of shorter duration be added to avert possibly adaptative changes in maternal homeostatic systems. Greater diversity of test animals, beyond the rodent-rabbit species largely used today, is urged with the objective of better matching metabolic pathways in a test animal to those of man. The demonstration of an embryotoxicity effect-level must be regarded as essential in all tests, and once found this level should be used as the basis of extrapolating downward to find an acceptable tolerance level of dosage. More attention should be focused on postnatal functional evaluation after prenatal and perinatal exposure of test animals to environmental chemicals, especially those that might interfere with the maturation of the central nervous system, endocrine glands, and immunological mechanisms. The use of nonhuman primates should be reserved for the testing of drugs essential for use during human pregnancy or those likely to be taken inadvertently during early pregnancy, because of the scarcity of such animals and the high costs of doing meaningful tests with them.
Test Systems for Assessing Mutagenic Potential of Chemical Substances
Authors: Flamm W Gary
Published: February 2020

The first report that certain chemicals have the potential of inducing heritable effects (mutation) appeared in the mid-1940’s. Two decades passed before this and subsequent observations were translated into a concern that some of the chemicals to which we are exposed may constitute a hazard to man’s genetic material and hence a threat to future generations of individuals. Such concern has led to the gradual evolution of the newest subdiscipline of toxicology, genetic toxicology. This subdiscipline is still young and faces many challenges in terms of developing sound toxicologic approaches for meeting specific evaluation needs in the interest of public health. This paper describes the current status of efforts in genetic toxicology and the types of steps which must be taken in order to begin to meet the needs and requirements of regulatory agencies.
Summary
Authors: Borzelleca Joseph F
Published: February 2020

Two kinds of problems associated with developing standardized procedures for the safety evaluation of new compounds are identified. The first of these is the question of the desirability of using such standard methods. It is concluded that a basic set of procedures is to be recommended, but this should be supplemented with special tests as may be indicated. The second problem is connected with the technical difficulties of any given type of assay and is normally dealt with in terms of the state of the art at the time. Assays by the inhalation route tend to be custom designed and do not follow standard protocols. One of the causes of this situation is the propensity of individual investigators to design de novo the equipment used to effect exposure of animals to airborne substances. Second, some confusion exists because investigators do not always appreciate that the concentration-time product is not the same as the true dose received by the exposed subjects and this may lead to anomalies when dose-response relationships are being characterized. It is suggested that interlaboratory studies be undertaken to ascertain the variability that might be expected in independent assays of inhalation toxicity.
Bioaccumulation of Chlorinated Paraffin Residues in Fish Fed Chlorowax 500C
Authors: Lombardo Pasquale , Dennison J Lawrence , Johnson W Waynon
Published: February 2020

Fingerling rainbow trout were fed a diet fortified with 10 ppm Chlorowax 500C, a chlorinated paraffin, for up to 82 days. Chlorinated paraffin residues as high as 1.1 ppm (tissue basis) were found. Recoveries from fortified fish tissue were greater than 92%, and the method sensitivity (tissue basis) is at least 0.5 ppm. Ultraviolet irradiation of the sample extracts and microcoulometric gas chromatography minimized interferences. No gross toxicological effects were noted in the experimental fish, although their weight gain was less than that of the controls.
A Review of Bromine Determination in Foods
Authors: Getzendaner Milton E
Published: February 2020

Organic compounds containing bromine, including methyl bromide, ethylene dibromide, and l,2-dibromo-3-chloropropane, have been used extensively for the fumigation of foods, or soils in which foods grow, making it necessary to determine residues of bromine and bromine-containing organic compounds. A large number of methods for the determination of bromine in foods, as organic, inorganic, and combined total bromide, have been developed. In methods for organic bromide, the bromine is converted to the inorganic form for measurement by titration, photometry, or other means. In recent years, instrumental methods have been developed in which the total bromine in the sample is determined, regardless of the state in which it exists. X-ray fluorescence and neutron activation analysis are the 2 instrumental methods used most widely. Residue data are presented for some typical bromine-containing samples.
Thin Layer Chromatographic Separation and Spectrodensitometric Determination of Higher and Lower Sulfonated Subsidiary Dyes in FD&C Yellow No. 6
Authors: Bell Sandra
Published: February 2020

A thin layer chromatographic method is presented by which higher and lower sulfonated subsidiary dyes are simultaneously separated from FD&C Yellow No. 6. After separation, the colors are quantitated directly, using a spectrodensitometer. Recoveries of 1, 2, and 5% of added 1-(4-sulfophenylazo)-2-naphthol-3,6-disulfonic acid ranged from 92 to 111%. Recoveries of 1, 2, and 5% of added l-(4-sulfophenylazo)-2-naphthol ranged from 90 to 110%.
High-Pressure Liquid Chromatographic Method for the Determination of Patulin in Apple Butter
Authors: Ware George M
Published: February 2020

Patulin is extracted from apple butter samples with ethyl acetate and the extract is cleaned up on a silica gel column, using benzene-ethyl acetate (75+25) as the eluant. High-pressure liquid chromatography, using a 25 cm Zorbax-Sil column, isooctane-ethyl ether-acetic acid (750+250+0.5) as the mobile solvent, and a 254 nm ultraviolet detector, is used for the determinative step. Under these conditions, patulin is eluted before 5-hydroxymethylfurfural, a component of apple butter which interferes with other liquid chromatographic and thin layer chromatographic methods. Recoveries of patulin added at levels of 34.6, 138.4, and 276.8 μg/kg ranged from 89.0 to 112.1%.
Fluorometric Measurement of Aflatoxin Adsorbed on Florisil in Minicolumns
Authors: Velasco James
Published: February 2020

Filter fluorometers have been adapted to measure the fluorescence intensity of aflatoxin adsorbed on a Florisil layer in minicolumns. The relationship between concentration and intensity is near linear in the aflatoxin range from 10 to 100 ng. Although individual aflatoxin fractions cannot be resolved, since the measure is one of total intensity, fluorometric measurements advance the minicolumn screening procedure to a semiquantitative level. The detection of 1 ng aflatoxin B1 is well within the limits of a filter fluorometer with a photomultiplier detector. A precision, expressed as percent coefficient of variation, ranging from 1.2 to 4.2%, was obtained for standard B1 columns.
Collaborative Study of the Elemental Analysis of Plant Tissue by Direct Reading Emission Spectroscopy
Authors: Jones J Benton
Published: February 2020

Eleven laboratories collaboratively studied the use of direct reading emission spectroscopy, with the solution rotating disk technique of excitation for the elemental analysis of plant tissues: aluminum, barium, boron, calcium, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, sodium, strontium, and zinc in alfalfa, citrus leaves, orchard leaves, pine needles, and tomato leaves. Since not all direct reading emission spectrographs are alike in all features, provisions were made to accommodate these differences relating to sample preparation, selection of the internal standard, and method of sample excitation. The sample is dry ashed and the ash is dissolved in an acidic buffer solution. Coefficients of variation obtained in the collaborative study ranged from 3 to 50%. For most plant tissue samples and elements, the value is less than 20%. The results obtained with direct readers are generally better than those obtained on photographic instruments and comparable to those obtained by atomic absorption spectroscopy. Direct reading emission spectroscopy is rapid, providing 14 elemental analyses in generally less than 1 min for a prepared sample. The method has been adopted as official first action.
Microdetermination of Bioethanomethrin
Authors: George Donald A , Mcdonough Leslie M
Published: February 2020

A microanalytical method was developed for the determination of the experimental synthetic pyrethroid insecticide Bioethanomethrin ((5- benzyl-3-furyl) methyl trans-(+)-3-( cyclopentylidenemethyl)-2,2 -dimethylcyclopropanecarboxylate). After saponification, trichloroacetyl chloride is used to form an ester from the alcohol moiety, and trichloroethanol is used to form an ester from the acid moiety. Infrared and mass spectral data support the expected structures of the derivatives formed. Nanogram sensitivity is realized by utilizing a gas chromatograph with an electron capture detector.
Automated Method for the Determination of Niacin and Niacinamide in Cereal Products: Collaborative Study
Authors: Gross Anthony F
Published: February 2020

In a collaborative study, an automated method for the determination of niacin and niacinamide in cereal products was compared with the official final action microbiological (43.121–43.125) and chemical (43.044–43.046) methods. Ten samples of cereal products, including enriched flour, yeast-leavened baked products, fortified breakfast cereals, and baked pet food products, were submitted to 14 laboratories. Nine laboratories reported values by the automated method, 6 reported values by the microbiological method, and 7 reported values by the chemical method. The results from the microbiological method were not subjected to analysis of variance because of the unusually large between-laboratory variation. The between-laboratory coefficients of variation for the automated and chemical methods were 10.90 and 10.18%, on the basis of results from 7 and 4 laboratories, respectively. There was no significant (p>0.05) difference between methods when results from the 4 laboratories who used both methods were compared. The automated chemical method has been adopted as official first action.
Spectroscopic Properties of the Methyl Esters of Chlorophenoxy Acid Herbicides
Authors: Van Peteghem Carlos H , Heyndrickx Aubin M
Published: February 2020

The mass and infrared spectra of the methyl esters of 9 chlorophenoxy acid herbicides are presented. Ultraviolet data are discussed and proton magnetic resonance spectra are tabulated. Because of the sensitivity of the technique, the mass spectra are most useful for the identification of those compounds in residues, especially by combined gas chromatographymass spectrometry. The pure herbicides used for the recording of the spectra were obtained by synthesis and recrystallization.
Thin Layer Chromatographic Detection and Indirect Gas Chromatographic Determination of Three Carbamate Pesticides
Authors: Ernst George F , Röder Saskia J , Tjan Gwan H , Jansen John T A
Published: February 2020

Carbamate pesticide residues are extracted from vegetables and fruits with methylene chloride. The extracts are spotted on silica gel plates and the pesticides are detected by an enzymatic inhibition technique. For quantitative determination, aliquots of the methylene chloride extracts are evaporated to dryness in a rotary evaporator. After the residues are dissolved in ethanol, 0.5N NaOH is added in the hydrolysis step. To remove a number of possible interferences the hydrolyzed phenols are steamdistilled and treated with l-fluoro-2, t-dinitrobenzene and/or 4-chloro-α,α,α-trifluoro-3,5-dinitrotoluene to form the ether derivatives. Efficiency in the conversion of the phenolic moieties to the phenyl ethers is about 100%. The resulting electron-capturing derivatives enable the carbamate pesticides to be detected in vegetables and fruits at the 0.05 ppm level. Recoveries of 90–94% were obtained from vegetables and fruits fortified with 0.5–2.0 ppm carbaryl, Mesurol, and propoxur.
Determination of Methylene Chloride, Ethylene Dichloride, and Trichloroethylene as Solvent Residues in Spice Oleoresins, Using Vacuum Distillation and Electron Capture Gas Chromatography
Authors: Page B Denis , Kennedy Barry P C
Published: February 2020

A quantitative gas chromatographic (GC) method is described for the determination of residual methylene chloride, ethylene dichloride, and trichloroethylene in spice oleoresins. The proposed method involves vacuum distillation in a closed system with toluene as a carrier solvent. Quantitation by electron capture GC on Porapak Q is facilitated by water extraction and by the addition of trans-l,2-dichloroethylene as an internal standard. Recoveries from oleoresins spiked at 30, 15, and 6 ppm ranged from 93 to 102%. To assess the possibility of interference from spice volatiles, the procedure was applied to 17 different spice oleoresins from 3 different manufacturers. No interferences were found, but methylene chloride levels up to 83 ppm and ethylene dichloride levels up to 23 ppm were detected. Trichloroethylene was not detected in any of the oleoresins.
Effect of Carbohydrates on the USP Test for Readily Carbonizable Substances
Authors: Dokladalova Jarmila , Upton Ronald P
Published: February 2020

Carbohydrates, when present as impurities in certain types of samples, have a strong effect on the USP test for readily carbonizable substances. In some instances as little as 50 µg carbohydrate, e.g., glucose, drastically increases the result of the test. The reaction mechanism is discussed and the carbonization potential of individual carbohydrates is evaluated.
Improved Cleanup Technique for the Estimation of Endosulfan and Endrin Residues
Authors: Kathpal Trilochan S , Dewan Ram S
Published: February 2020

An improved cleanup technique has been developed for the extraction of endosulfan and endrin from crops. The technique involves the use of Nuchar C-190N as adsorbent and a mixture of n-hexane and acetone (4+1) as the eluting solvent. The mean percentage recoveries of endosulfan (I and II) and endrin from plant tissue extracts fortified at levels of 0.5–2.0 ppm varied from 86 to 102 and 97 to 100, respectively.
A Practical Method for the Comparison of Mineral Wool Insulations in the Forensic Laboratory
Authors: Miller Elmer T
Published: February 2020

The comparison of glass wool, slag wool, and rock wool insulations by means of refractive index and dispersion is practical and effective. The material is annealed at >1150°–1200°F; this process burns off the resinous coating and leaves the fibers and slugs suitable for microscopic study, solubility tests, fluorescence observations, and refractive index and dispersion measurements. Refractive index and dispersion values for the annealed fibers are obtained by the Emmons double variation method, using a hot stage, a monochromator, and a phase microscope. In a study of 34 mineral wool insulations, a range of refractive indices was obtained that was 7 times the range exhibited by window glasses. In one case the value of the method was proven when insulations from 3 sources were each matched with fibers and slugs from a suspect’s clothes.
Infrared Identification Test for Scopolamine as the Hydrobromide
Authors: Brannon Wilson L , Levine Joseph
Published: February 2020

The method of preparation of scopolamine hydrobromide affects the infrared (IR) spectrum of the product. A column chromatographic procedure is used to both isolate the drug from tablets and injections and form the hydrobromide salt. This yields reproducible IR spectra and thus constitutes an identity test for scopolamine hydrobromide.
Colorimetric Determination of Diazepam in Pharmaceutical Preparations
Authors: Baggi Tulsidas R , Mahajan Surinder N , Rao Griddaluru Ramana
Published: February 2020

A colorimetric method is presented for the estimation of diazepam as the pure drug and in formulations. Diazepam is hydrolyzcd with 6N HC1 to 2-methyIamino-5-chlorobenzophenone, which is extracted with chloroform to give a yellow solution whose absorbance is measured at 410 nm against a solvent blank. The color obeys Beer's law in the concentration range of 0–30 μg/ml. In 5 determinations, recovery was 99.0±1.9%. The method is applicable to pure diazepam and its formulations for oral and parenteral use. No interferences were observed from pyridoxine hydrochloride and commonly used preservatives, vehicles, and colors.
Nitrate Determination in Baby Food, Using the Nitrate Ion Selective Electrode
Authors: Pfeiffer Sandra L , Smith Jean
Published: February 2020

The nitrate electrode has been utilized in the determination of nitrate content in food products. The AOAC xylenol method was employed for comparative results. A reasonable correlation (r = 0.91) was found between the 2 methods in the analysis of 49 samples containing 30–350 ppm nitrate. At the average nitrate content (100 ppm) of these foods, the standard error was 4.3 ppm. The electrode responds directly to the ionic activity of the nitrate ion. It has a linear concentration range of 1–6000 ppm nitrate and can be used over a wide pH range. The electrode does respond to some extent to anions other than nitrate, and some interferences do occur. These interferences are easily controlled by the use of cation exchange resins. The Corning known addition (spiking) method is used on all samples to insure correct electrode response in solutions containing variable background ionic composition. The electrode has the advantage of simplicity, speed, reproducibility, and accuracy. Work time saved using the electrode as opposed to the xylenol method is about 7 hr for the analysis of 20 samples. Error, and the need for repeating analysis, is much less frequent.
Spectrophotometric Determination of Boron in Boronated Fertilizers
Authors: Neuner Terry E , Pickett Edward E , Gehrke Charles W
Published: February 2020

Acid-soluble boron in fertilizers is complexed in acid solution with 2-ethyl-l,3-hexanediol and extracted into methyl isobutyl ketone. The extract is nebulized into an air-hydrogen flame and the intensity of emission of the BO2 molecule is measured at 518 inn. The method is convenient and inexpensive and provides detection limits of 0.1 ppm. The method was tested on 6 fertilizer samples with the relative standard deviation varying from 5.6% on a 0.053% (w/w) sample to 2.6% on a 7.81% (w/w) sample. The recovery of added boron ranged from 94.5 to 104.2% with an average recovery of 99.7%.
Automated Flame Photometric Determination of K2O in Fertilizers
Authors: Neuner Terry E , Pickett Edward E , Gehrke Charles W , Wippler John F
Published: February 2020

The well known chemical interference of phosphorus on the emission of potassium in cool flames was verified and found to cause small but significant error in using the official final action AOAC method of analysis. This effect can be greatly reduced by incorporating the use of lanthanum along with the internal standard, lithium. Lanthanum has been shown to reduce the chemical interference of phosphorus by chemical bonding without affecting potassium or lithium emission characteristics. The resulting manifold can be used to analyze samples at the rate of 6 0 / h r with no significant interference.
Evaluation of the Babcock Method for the Determination of Milk Fat
Authors: Mckinley Myron R , Arnold Richard E , Rosenbury John B , Born Earl C , Dunham Chapman E , Park Douglas L
Published: February 2020

The Babcock test for fat in milk was evaluated to study the effects of variables such as glassware calibration, sample preparation, sample composition, reagents, tempering conditions, procedural variations, and analyst. Certain test bottles yielded significantly different results; however, there was little indication of pipet variation. Analysis of the various techniques for tempering and mixing indicated that samples tempered at 68°F (20°C), containing an airspace of approximately 25% of the total container, and mixed by inversion 5–10 times or poured from one container to another gave the most consistent results. Sample composition did not affect results, provided all milk-solids-notfat were digested by the sulfuric acid. A pipet draining time of 10 sec followed by blowing out the pipet was sufficient to yield reproducible results. Differences between lots of sulfuric acid affected results. Results were 0.027% less when the final test tempering was 130°F (54.5°C) compared to 140°F (60°C); however, a final tempering for a minimum of 3 min gave satisfactory results. Variations in reading results between individual analysts were negligible. The Babcock method for fat in milk, modified to include the optimum parameters as determined in this study, was subjected to a collaborative study. Nine laboratories analyzed 10 samples in duplicate. Statistical analysis of collaborative data indicates a significant difference between laboratories (p <0.01 ). The repeatability standard deviation of the method is 0.0183%. The reproducibility standard deviation is 0.0407%. The repeatability and reproducibility coefficients of variation are 0.53 and 1.17%, respectively. On the basis of the collaborative results, the following changes have been incorporated into the official final action method: specifications for the reading light; sample draining time; tempering temperature of the acid; tempering procedure for reading the test bottle.
Determination of Polybrominated Biphenyl Residues in Dairy Products
Authors: Fehringer Norbert V
Published: February 2020

A method for the determination of polybrominated biphenyls (PBBs) in dairy products is described. Fat is extracted from the products by the official AOAC method. The PBB residues are separated from the fatty material by gel permeation chromatography prior to gas-liquid chromatographic (GLC) quantitation. An additional cleanup using petroleum ether elution through a miniature Florisil column is necessary for thin layer chromatographic (TLC) confirmation. Recoveries of PBBs from samples fortified at levels from 0.1 to 0.5 ppm ranged from 94 to 104% with an average of 99%. GLC sensitivity permits the estimation of PBB residue levels as low as 0.007 ppm. Routine TLC confirmation is limited by sensitivity to ≥0.2 ppm.
Radioassay of Chromic Phosphate 32P Suspension by Cerenkov Counting
Authors: Heitzman Martin W , Ford Leonard A
Published: February 2020

A simple and precise method is presented for the radioassay of chromic phosphate 32P suspension by Cerenkov counting. An aliquot is weighed, dissolved, diluted, and then counted directly in a conventional liquid scintillation counter. The internal standard technique is used to provide color quench correction. This method is particularly useful for high specific activity samples. The standard deviation for the analysis of 3 aliquots, each determined in triplicate, was 1.9%.
Determination of Fluoride in Vegetation: A Comparative Study of Four Sample Preparation Methods
Authors: Van Den Heede Marc A , Heyndrickx Aubin M , Van Peteghem Carlos H , Van Zele Wilfried A
Published: February 2020

Four sample preparation methods (dilute acid digestion, concentrated acid digestion, alkali fusion, and low temperature ashing) for the determination of fluoride in vegetation are compared. A fluoride ion selective electrode is used for the final quantitative measurements. Ionic strength and pH are maintained by a concentrated citrate buffer. The highest sensitivity and reproducibility are obtained by low temperature ashing of the dry sample. Several vegetables, grown in the neighborhood of a glaze factory, were simultaneously analyzed by 2 of the methods, the dilute acid digestion and the low temperature ashing procedures. The higher fluoride content found with the latter technique is attributed to the complete mineralization of the sample.
Data Fitting by Least Squares
Authors: Alvarez-Nazario Fabian
Published: February 2020

Two methods for use with equally or unequally spaced data are presented and compared. A common notation shows their close relationship. Calculations of the standard error of estimate and coefficient of correlation are also demonstrated and discussed. The use of electronic desk calculators is emphasized.
Gas-Liquid Chromatographic Determination of Naled in Pesticide Formulations
Authors: Carlstrom A Aner
Published: February 2020

Dusts, emulsions, concentrates, and technical material covering a wide range (1%92%) of naled were diluted or extracted with chloroform. Dibutyl phthalate was added to sample extracts as an internal standard before gas-liquid chromatographic (GLC) injection. Twelve column packings covering the entire polarity scale were tested, and 3% XE-60 was chosen, based on the best resolution for a difficult-to-separate low volume concentrate. Response is linear from 1 to 50 mg naled/ml and the coefficient of variation for the GLC step is 0.81%. Of 29 other active ingredients which have been formulated with naled, diazinon and 1 isomer of BHC elute with naled, while dicrotophos elutes with the internal standard.
Colorimetric and Volumetric Assays of Colchicine in Galenicals and in Pharmaceutical Preparations
Authors: Karawya Mohamed S , Diab Aly M
Published: February 2020

In the method described the amide group in the colchicine molecule is reduced with lithium aluminum hydride to the corresponding secondary amine. The latter is extracted with chloroform and then determined either colorimetrically by the copper dithiocarbamate reaction or volumetrically by dissolving in acid and titrating with sodium hydroxide or perchloric acid. The results were comparable with those obtained by the Egyptian Pharmacopoeia spectrophotometry method.
Chromatographic Methods for the Analysis of Hexachlorobenzene and Possible Metabolites in Monkey Fecal Samples
Authors: H Yang Raymond S , Coulston Frederick , Golberg Leon
Published: February 2020

The separation and identification of hexachlorobenzene (HCB), pentachlorobenzene (QCB), and pentachlorophenol (PCP) by thin layer, high-pressure liquid, and gas chromatography are reported. Satisfactory results were obtained with reverse phase thin layer and highpressure liquid chromatography. The 2 gas chromatographic columns tested gave adequate separation of HCB and QCB. A PCP methylation process using dimethyl sulfate was attempted. Procedures are presented for extraction, cleanup, separation, and identification of HCB and possible metabolites from feces of a rhesus monkey treated with 14C-HCB. Recovery of radioactivity in excess of 96% was attained in extracts from feces by these methods. Preliminary evidence suggests the formation of PCP and possibly other polar metabolites from HCB in the rhesus monkey.
Gas-Liquid Chromatographic Determination of Vinyl Chloride in Vinyl Chloride Polymers, Food-Simulating Solvents, and Other Samples
Authors: Breder Charles V , Dennison J Lawrence , Brown Margaret E
Published: February 2020

The determination of vinyl chloride (VC) in polyvinyl chloride (PVC), vegetable oils, foodsimulating solvents, mouthwashes, and blood anticoagulant solutions by gas-liquid chromatography is described. PVC polymers are dissolved in either tetrahydrofuran or dimethyl acetamide. Vegetable oils are diluted with an equal volume of tetrahydrofuran. The resulting solutions are injected into a gas-liquid chromatograph equipped with a flame ionization detector. Mouthwashes, blood anticoagulant solutions, and 3 food-simulating solvents, 3% acetic acid, 50% ethanol, and heptane, are analyzed by direct injection into a chromatograph. Sensitivities are such that 0.05 ppm VC in solution or 1 ppm VC in PVC can be quantitated.
A Screening Method for Determining Nitrofuran Drug Residues in Animal Tissues
Authors: Ryan John J , Lee Young C , Dupont Jo A , Charbonneau Claudette F
Published: February 2020

A method was developed for measuring low levels of total nitrofurans in animal tissues and milk. The antimicrobial nitrofurans (5 or more products) used in agriculture are extracted from tissue with aqueous acid in the presence of ethyl acetate. After centrifugation and evaporation, the organic residue is washed with hexane and the nitrofurans are hydrolyzed to 5-nitrofuraldehyde in aqueous acid at 70°C. The hydrolysis product is extracted with benzene and measured by gas-liquid chromatography with electron capture detection. Recoveries of nitrofurazone and furazolidone from fortified poultry and swine tissues at the levels of 0.5 and 0.1 ppm are 75 and 65%, respectively. This procedure can be used to detect the total nitrofuran content of as little as 10 ppb muscle tissues and milk, 100 ppb liver, and 50 ppb fat with no interference from related veterinary nitrodrugs.
Collaborative Study of a Spectrophotometric Method for Determining Maleic Hydrazide Residues in Tobacco and Vegetables
Authors: Ihnat Milan , Thompson Brian
Published: February 2020

A distillation-spectrophotometric method for the determination of maleic hydrazide residues in tobacco and vegetables reported previously was studied collaboratively. Ten laboratories submitted analytical results on 10 samples containing residues resulting either from field treatment or laboratory fortification. The samples were estimated to contain from 0.99 to 16.36 μg maleic hydrazide/0.5 g sample analyzed. The coefficients of variation based on precision standard deviation ranged from 57.7% for the lowest residue content to 32.4% for the highest. The corresponding coefficients of variation based on overall standard deviations were estimated to be at least one-fifth larger. Strong evidence of systematic laboratory differences was found (F-test, significant at 0.1%). Apparent recoveries of 10.0 fifl maleic hydrazide added to 0.5 g fluecured tobacco and potato were 97.3 and 89.7%, respectively. Apparent recoveries of 16.0 and 16.5 μg added to 0.5 g green bean were 87.4 and 85.5%, respectively. The precision of the method studied was no better than that of the current official final action method, 29.121–29.127, and its adoption is not recommended.
Resolution of Aflatoxins B1, B2, G1, and G2 by High-Pressure Liquid Chromatography
Authors: Pons Walter A
Published: February 2020

Aflatoxins were completely resolved as sharp peaks in the order B1-B2-G1-G2 by high-pressure liquid chromatography on a small particle (10 μm) porous silica gel column in 7–13 min (B1 through G2) by a water-saturated chloroform-cyclohexane-acetonitrile elution solvent (25+7.5+1.0), with detection by ultraviolet absorbance at 360 nm. The relationship between peak height and amount injected was linear over a 5–400 ng range for each aflatoxin. Both retention times and peak heights were highly reproducible, multiple injections of mixed standards giving coefficients of variation of 1.0–1.4% (retention time) and 1.6–2.8% (peak height) for the 4 aflatoxins. Detection was highly sensitive, with mean peak height, mm/ng, of 7.1 (B1), 6.4 (B2), 4.5 (G1), and 4.1 (G2), allowing detection of 1–2 ng of each aflatoxin.
Quantitative Determination of 4,4′-(Diazoamino)-dibenzenesulfonic Acid in FD&C Yellow No. 6 by Elution Chromatography
Authors: Fratz D Douglas , Bailey John E
Published: February 2020

An elution chromatographie procedure is presented which separates 4,4′-(diazoamino)-dibenzenesulfonic acid (DAADBSA) from FD&C Yellow No. 6 The DAADBSA is determined spectrophotometrically. Recoveries of DAADBSA added to FD&C Yellow No. 6 at levels of 0.03 to 0.2% ranged from 94 to 104%. DAADBSA was found in commercial samples of FD&C Yellow No. 6 in amounts ranging from 0.036 to 0.23%.