bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Feed Grains and Forages for Traces of Cobalt by Flameless Atomic Absorption Spectroscopy
Authors: Hageman Lynn , Torma Laszlo , Ginther Burton E
Published: February 2020

Flameless atomic absorption spectroscopy (AAS) has been used for the analysis of cobalt (5–200 ppb) in plant material. An ashing temperature study shows that some cobalt may be lost at temperatures >500°C. Direct methods using the carbon rod atomizer have been unsuccessful because of large non-atomic absorption and other interference problems. Calcium, iron, magnesium, and manganese can cause interference. An extraction technique using 1-nitroso-2-naphthol as a chelating agent is recommended for routine analysis. Samples are dry ashed, dissolved in dilute HC1, and extracted with 1-nitroso-2-naphthol-chloroform, and the cobalt level is determined by flameless AAS.
A Rapid Screening Method for the Determination of Di-(n-octyl) Tin Stabilizers in Alcoholic Beverages, Using a Heated Graphite Atomizer
Authors: Méranger Jean-Charles
Published: February 2020

A method is described for the rapid screening of di-(n-octyl) tin stabilizers in alcoholic beverages, using a heated graphite atomizer coupled to an atomic absorption spectrophotometer. Benzene can selectively extract di-(ra-octyl) tin stabilizers in the presence of inorganic tin. Nuclear magnetic resonance spectroscopy is used to confirm the presence of the ra-octyl grouping in a benzene extract of a plastic container and x-ray fluorescence spectrometry is used to follow the efficiency of the purification steps. The tin content of 5 types of plastic containers presently used in Canada for the storage of alcoholic beverages was obtained by x-ray fluorescence spectrometry and levels of up to 1700 μg Sn/g plastic were found. The alcoholic beverages contained therein, which included 22 samples of gin, martini, cognac, red wine, and sherry, were analyzed for di-(n-octyl) tin content. Although the method used will detect 0.04 ppm Sn, there was no evidence of leaching in any of the samples analyzed.
Gas Chromatographic Determination of Diols and Glycerol in Flavor Bases and Flavored Wines
Authors: Martin Glenn E , Dyer Randolph H , Figert Donald M
Published: February 2020

The determination of diols and glycerol in alcoholic products was investigated by gas chromatographic procedures based on gas adsorption, gas partition, or a combination of these. The best precision and accuracy were obtained by gas-partition chromatography, using SP-1000 as the liquid phase. The limits of detection were 0.04% for 1,2-propanediol, 1,3-propanediol, 2,3-butanediol, or 1,3-butanediol, and 0.5% for glycerol. The gas-partition chromatographic procedure is fast, precise, and accurate. The preparation of standards and samples can be carried out with ease.
Thermal Susceptibility of Salmonella in the Moroccan Food Snail, Helix aspersa
Authors: Andrews Wallace H , Wilson Clyde R
Published: February 2020

Thirty samples of 10–15 Helix aspersa food snails were examined for Salmonella by a surface rinsing method and by analysis of whole snails rinsed with 70% ethanol. Thirteen samples were positive by the rinsing method and 6 were positive by whole snail analysis, with this difference being significant (P < 0.01). Although Salmonella contamination in H. aspersa appeared to be predominantly surface, the pathogen was also found within the snail meat. The ability of surface and subsurface Salmonella organisms to survive in cooked snails was determined in 90 samples. Thermocouple readings indicated that an internal temperature of at least 200°F (93°C) was reached within the snail meat during cooking by a typical recipe. This temperature was sufficient to kill both surface and subsurface Salmonella in 29 samples positive for the pathogen prior to heating, A variety of serotypes representing several somatic groups was isolated.
Determination of Amphetamine by Schiff Base Formation and Quantitative Gas-Liquid Chromatography
Authors: Clark Charles C
Published: February 2020

A procedure was developed to determine amphetamine salts in solid dosage forms. Amphetamine was extracted from the solid matrix with dilute hydrochloric acid and reacted with cyclohexanone in a strongly basic aqueous methanolic solution. The Schiff base reaction product was extracted with hexane for gas chromatographic determination. Reaction time and optimum conditions were studied. Phcnethylamine, similarly treated, was used as an internal standard. Results compared favorably with those obtained by using USP methods.
Detection of Twelve Mycotoxins in Mixed Animal Feedstuffs, Using a Novel Membrane Cleanup Procedure
Authors: Roberts Basil A , Patterson Deryck S P
Published: February 2020

A multimycotoxin thin layer chromatographic screening method is described which is applicable to most animal feedstuffs. Interference from nonspecific lipid, pigment, and other components of simple and mixed feeds is reduced to a minimum by using a membrane cleanup step. Aflatoxins B1, B2, G1, and G2, citrinin, diacetoxyscirpenol, ochratoxin A, patulin, penitrem A, sterigmatocystin, T-2 toxin, and zearalenone may be reliably detected. The sensitivity of the method is generally low for mixed feeds but even so aftatoxin B4 can be detected at a level of 3 ppb and ochratoxin A at 80 ppb. While the basic method is less sensitive for sterigmatocystin (330 ppb), patulin (600 ppb), zearalcnone (1000 ppb), and the trichothecenes (1000–4000 ppb), it may be adapted so as to reduce the above detection limits when the presence of these toxins is suspected. Lower levels may be detected in extracts of simple feeds.
Confirmation of Polybrominated Biphenyl Residues in Feeds and Dairy Products, Using an Ultraviolet Irradiation-Gas-Liquid Chromatographic Technique
Authors: Erney D Ronald
Published: February 2020

An ultraviolet (UV) irradiation-gas-liquid chromatographic (GLC) detection procedure was used to confirm the presence of polybrominated biphenyl (PBB) residues in sample extracts after GLC quantitation. Chromatograms of PBB standard and sample extract solutions showed similar photodecomposition peak patterns dependent on time and intensity of UV irradiation. Confirmation of PBBs in sample extracts by this procedure was possible for any amount detectable by the GLC system employed. Prolonged UV irradiation resulted in complete disappearance of all PBB peaks from the chromatogram, permitting their distinction from background peaks due to extraneous sample material unaffected by UV irradiation.
Analysis of Pesticides by Chemical Derivatization. I. A New Procedure for the Formation of 2-Chloroethyl Esters of Ten Herbicidal Acids
Authors: Chau Alfred S Y , Terry Ken
Published: February 2020

A new esterification procedure was developed to form 2-chloroethyl esters for 10 common herbicidal acids, using dicyclohexyl carbodiimide and 2-chloroethanol. This reagent was found to be more desirable than the commonly used boron trichloride/2-chloroethanol reagent. Maximum esterification was given for picloram at a lower reaction temperature with a shorter reaction time. Also, maximum esterification of dicamba and 2,3,6-TBA was achieved. The boron trichloride/2-chlorethanol gave poor or little esterification with these 2 acids under the various conditions investigated. The effect of solvents on esterification with the 2 reagents was also explored.
Survey for Aflatoxins and Zearalenone in 1973 Crop Corn Stored on Farms and in Country Elevators
Authors: Stoloff Leonard , Henry Sara , Francis Octave J
Published: February 2020

A total of 315 marketable and 57 obviously damaged corn samples were collected at 116 different farms and country elevators located in the United States in counties selected from among those producing more than 1 million bushels of corn in 1972. The samples were analyzed for aflatoxins and zearalenone. The most striking correlations observed were between geographical area and mycotoxin contamination. Aflatoxin contamination was most frequently encountered in the Southeast-Appalachia areas with a 44% incidence of marketable corn with detectable aflatoxins. Zearalenone was most frequently encountered in the Corn Belt with a 10% incidence in marketable corn from that region. When mycotoxin contamination was found in an establishment, most of the samples from that establishment were contaminated. There was no correlation between mycotoxin contamination and storage practices nor could the observed contamination of marketable corn be related to the contamination of the obviously damaged grain. These observations plus correlations with the geographic incidence and aflatoxin level distribution of published field contamination data suggest the possibility of a common contamination mode.
Collaborative Study of an Extension of the Mills et al. Method for the Determination of Pesticide Residues in Foods
Authors: Finsterwalder Charles E
Published: February 2020

Fifteen laboratories collaboratively determined parathion, o,p′-DDT, p,p′-DDT, and p,p′-DDE in kale, and lindane, dieldrin, heptachlor epoxide, and p,p′-DDE in eggs, using electron capture gas-liquid chromatography (potassium chloride thermionic detector for parathion). Pesticide levels ranged from 0.033 ppm heptachlor epoxide to 3.32 ppm p,p′-DDT. Mean recoveries (± standard deviations) were: parathion 91±15%, o,p′-DDT 99±8%, p,p′-DDT 97±8%, lindane 94±4%, dieldrin 106±8%, heptachlor epoxide 106±5%, p,p′-DDE 94±8% in eggs and 101±9% in kale. The methods have been adopted as official first action.
Automated Gel Permeation Chromatographic Cleanup of Animal and Plant Extracts for Pesticide Residue Determination
Authors: Johnson Lyle D , Waltz Ralph H , Ussary James P , Kaiser Floyd E
Published: February 2020

Applications of an improved gel-solvent system for cleanup of pesticide residues by gel permeation chromatography (GPC) were investigated. Elution characteristics using Bio-Beads SX-3 gel and a toluene-ethyl acetate (1+3) elution solvent were determined for 16 nonicnic chlorinated pesticides, 3 polychlorinated biphenyls (PCBs), 14 chlorophenoxy herbicide esters, and 7 organophosphate insecticides. Elution patterns for vegetable and animal lipids were also studied. Quantitative recoveries of the pesticides were achieved. No liquid-liquid partitioning cleanup steps were required with any type of nonionic chlorinated pesticide or sample matrix. Only GPC cleanup was required for the nonionic chlorinated pesticides, PCBs, and organophosphate pesticide residues in chicken and turkey fat samples. Electron capture and flame photometric detectors were used in the gas chromatographic method for the respective pesticides. Samples containing up to 0.5 g lipid each were processed at the rate of one every 30–40 min with the automated system. Results were in excellent agreement with those from accepted manual partitioning methods and were achieved with significant savings of both labor and chemicals.
Substitution of Cupric Sulfate for Mercuric Oxide as Catalyst for the Kjel-Foss Instrument
Authors: Wall Larry L , Gehrke Charles W
Published: February 2020

A mixture of cupric sulfate and titanium dioxide and cupric sulfate alone were evaluated as possible catalysts to replace mercuric oxide in the determination of protein nitrogen, using the Kjel-Foss automated instrument. It was necessary to modify the instrument to increase the digestion time from 6 to about 12 min to achieve acceptable protein nitrogen recovery with cupric sulfate as the catalyst. An experimental sample set of nitrogen-containing salts and American Association of Feed Control Officials check feed samples were analyzed with the Kjel-Foss instrument in its standard configuration with mercuric oxide and as modified with cupric sulfate as the catalyst. The average per cent nitrogen, standard deviation, and relative standard deviation with mercuric oxide and cupric sulfate were 10.37 and 10.36, 0.040 and 0.042, and 0.53 and 0.56, respectively. The substitution of cupric sulfate for mercuric oxide is feasible, and it eliminates the use of the potential pollutant, mercury.
Substances Interfering with the Gas-Liquid Chromatographic Determination of T-2 Mycotoxin
Authors: Mirocha Chester J , Pathre Sadanand V , Behrens Jerome
Published: February 2020

Two substances interfering with the gas-liquid chromatographic (GLC) detection of the T-2 mycotoxin were identified as 1-glycerylmonooleate and 1-glycerylmonolinoleate. These monoglycerides are natural products formed by species of Fusarium growing on cereal grains and are also additives contained in liquid vegetable and animal fats added to the feed mixture. The monoglycerides can be removed from the analytical sample by resolution by thin layer chromatography prior to separation by GLC. Trimethylsilyl ether derivatives of the monoglycerides and T-2 toxin have almost identical retention times on 3% OV-1 columns, whereas the trifluoroacetyl and pentafluoropropionyl derivatives give baseline separation on the same column. The monoglycerides can be misidentified as the T-2 toxin in analyses involving GLC.
Collaborative Study of the Food Chemicals Codex Method for the Determination of the Neutralizing Value of Sodium Aluminum Phosphate
Authors: Park Douglas L
Published: February 2020

Fifteen laboratories participated in a collaborative study to evaluate the Food Chemicals Codex method for the determination of the neutralizing value of sodium aluminum phosphate. The AOAC method for determining the neutralizing value of sodium acid pyrophosphate, sec. 8.010, was also included in the study. The precisions of the Food Chemicals Codex method, based on the between-replicate standard deviation and on one collaborator making one determination, are 1.16 and 3.66, respectively. The Food Chemicals Codex method for the determination of the neutralizing value of sodium aluminum phosphate has been adopted as official first action.
The Relative Nitrogen Utilization Method for Evaluating Protein Quality
Authors: McLaughlan J Murray
Published: February 2020

A single-dose rat assay for protein quality called relative nitrogen utilization (RNU) is described. The method includes a factor for the protein utilized for maintenance. The protein quality of the test protein is expressed as a per cent of the value for Iactalbumin, the reference protein. For good quality proteins RNU gives results that are similar to those obtained by net protein ratio and relative protein value; for poor quality proteins RNU results fall between values by the other 2 methods. The protein efficiency ratio (PER) gives much lower values for poor quality proteins than any of the other 3 aforementioned methods and is influenced more by both level of protein and lipid in the diet. RNU is a more precise assay than PER as judged by the coefficient of variation.
Pathogenicity of Escherichia coli Recovered from Food
Authors: Mehlman Ira J , Fishbein Morris , Gorbach Sherwood L , Sanders Arvey C , Eide Elmer L , Olson Joseph C
Published: February 2020

In Western nations, pathogenic biotypes are sporadically encountered in foodborne gastroenteritis. Cholera, dysentery, and chronic ulcerative colitis syndromes are recognized. E. coli has been associated on the average with 2% of annual food outbreaks and 5% of total cases. In developing nations, the incidence may be greater. In contrast with Salmonella and Shigella, significance can be assessed only by fulfillment of Koch’s postulates. Preliminary studies using vascular permeability reaction for the detection of heat-labile toxin and the Sereny keratoconjunctivitis test for demonstration of invasiveness indicate limited incidence of these pathogenicity markers in cultures from foods. Two per cent of isolates from cheeses involved in recent outbreaks were toxigenic; 14% were invasive. Corresponding values for food isolates not associated with illness were 10 and 0, respectively. To facilitate examination of multiple isolates, 10 may be pooled for the detection of heat-labile toxin, and 5 for invasiveness. Present model pathogenicity systems require standardization, estimation of specificity and sensitivity limits, examination by collaborative study, and ascertainment of human equivalence. Supplemental tests include capacity for colonization of intestinal epithelium and intracellular growth. Stereotypes based upon serology, host range, and recognized toxic factors may require modification.
Use of a Round-Bottom Resin Kettle for in vitro Dissolution Testing
Authors: Kirchhoefer Ross D
Published: February 2020

Dissolution tests are used to assist in the evaluation of drug bioavailability. A piece of glassware has been designed which allows one to take advantage of the dissolution properties of a 3-neck round-bottom flask and is compatible with and easier to use than existing stirring and bath equipment.
Appraisal of Existing Methodology in Aspiration Toxicity Testing
Authors: Osterberg Robert E , Bayard Steven P , Ulsamer Andrew G
Published: February 2020

New methods or modifications of currently used methods in aspiration toxicology must be capable of accurately assessing the hazard and toxicity potentials of those products which are capable of being aspirated. The methods evaluated in the rat were intratracheal injections, intravenous injections, and modifications of the Gerarde technique. A product containing petroleum distillates and a standard viscosity petroleum distillate sample were administered to Osborne-Mendel rats, rabbits, and guinea pigs in ml/kg doses. The utility of the methods was determined by comparing lung weight increases, lung-body weight ratios, gross pathological lung changes, and mortality. The modified Gerarde technique showed the best potential for predicting aspiration hazard and toxicity based on the severity of the reactions which, using a radiolabeled oil, was shown to be a function of the amount of product which enters and reacts with the lungs. The influence of preventing the swallowing reflex to assure aspiration of the oil was assessed in the rat. The results show that less than 10% of the dose is aspirated when the swallowing reflex occurs. Methods of sacrifice were investigated for an effect on rat lung weight. No tested method except stunning with cervical dislocation produced an effect. Tests were conducted on rats and rabbits to determine differences in lung reactivity to the influence of inhalation anesthetics, pentothal sodium, or no anesthesia in response to petroleum distillate administration and to determine which test species is the better animal model. The results indicate that the rat is the better test model because of degree of lung reaction, size, and economy, and that inhalation anesthesia with ether is preferable over the other choices.
Collaborative Study of the Serological Identification of Staphylococcal Enterotoxins by the Microslide Gel Double Diffusion Test
Authors: Bennett Reginald W , McClure Foster
Published: February 2020

A collaborative study was conducted, using the microslide gel double diffusion test for enterotoxin detection by determining the staphylococcal enterotoxigenicity of 7 strains of Staphylococcus aureus. Two strains produced staphylococcal enteroloxin A (SEA), 2 strains produced staphylococcal enterotoxin B (SEB), one strain produced both SEA and SEB, and 2 strains produced neither SEA nor SEB. To ascertain the effectiveness of this method for the detection of enterotoxins, strains of enterotoxigenic staphylococci which produced small or relatively large amounts of toxin were used in the study. The cultures were grown on semisolid brain-heart infusion agar and the culture fluids were assayed serologically for SEA and SEB. The qualitative results of this study by 16 collaborators indicated that this technique, in general, demonstrated a high degree of specificity as well as simplicity and reproducibility in the identification of the enterotoxins. Of the 16 participating laboratories, 14 reported the correct diagnoses for the 7 staphylococcal strains studied and 2 laboratories determined 6 of the 7 strains correctly. Based on these results, this method has been adopted as official first action.
Mass Spectra of Sodium N-Alkyl and N,N-Dialkyl Dithiocarbamates and Some Related Compounds
Authors: Onuska Francis I , Comba Michael E
Published: February 2020

Electron impact mass spectra of 8 sodium alkyl and dialkyl dithiocarbamate salts are reported with the spectra of 2 dithiocarbamate zinc salts and N′,N′-dimetliyl-N,N-dimethylthiocarbamylsulfenamide. The investigated compounds all gave molecular ions, and generalized descriptions of their fragmentation behavior are presented.
Aflatoxin Occurrence on Raw and Cooked York Soybeans Inoculated With Three Aspergillus Isolates
Authors: Sherertz Peter C , Eadie Thomas , Young Joy W , Llewellyn Gerald C
Published: February 2020

Raw and cooked soybean media were inoculated in separate experiments with Aspergillus flavus NRRL 3251, A. flavus ATCC 15548, and A. parasiticus NRRL 2999 isolates. The total quantity of aflatoxins produced and the percentage distribution of aflatoxins B1, B2, G1, and G2 varied with the state of the medium (raw or cooked) and with the fungal isolate used. Cooked soybean medium supported higher aflatoxin production by A. flavus NRRL 3251 and A. parasiticus NRRL 2999 than did raw medium. Larger quantities of aflatoxins B1, B2, G1, and G2 were produced by A. flavus ATCC 15548 on raw soybean medium than were produced by any of the isolates on cooked medium. Application of these data is discussed briefly in relation to possible use of soybean media as a source of aflatoxin production.
Methods for the Determination of Calcium in Beer
Authors: West Dwight B
Published: February 2020

The American Society of Brewing Chemists (ASBC) has submitted 2 new analytical methods for the colorimetric determination of calcium in beer to the AOAC. These 2 methods give similar results and have been tested by an ASBC technical committee for 3 years. The methods have been adopted as official first action.
Infrared Identification of Maleic Acid in Pharmaceutical Maleate Salts
Authors: Brannon Wilson L , Schwartzman George , Levine Joseph
Published: February 2020

Difficulties are encountered in the USP melting point identification test for maleic acid extracted from chlorpheniramine maleate. A general procedure is described for the isolation and infrared identification of the maleic acid moiety of pharmaceutical salts from drug substances or dosage forms. This procedure permits the concurrent infrared identification of the amine moiety.
Collaborative Study of a Method for the Analysis of Metoxuron and Its Formulations
Authors: Sauer Horst H , Bosshardt Hans P
Published: February 2020

The method collaboratively studied is based on 3 steps: free interfering amines are removed by acid extraction; dimethylamine is liberated by alkaline hydrolysis; and the liberated amine is distilled into an absorbing solution and continuously titrated. Interfering byproducts are separately determined by a thin layer chromatographic method. Two samples of metoxuron, the technical active ingredient, and an 80% wettable powder, were analyzed by 18 collaborators from Europe, the United States, and South America; results were satisfactory with an overall coefficient of variation of about 0.8%. Only one outlier was noticed. The method was adopted in 1974 as a full CIPAC method. The method was adopted in 1975 as an official first action AOAC method.
Comparison of Antibiotic-Amended Potato Dextrose Agar and Acidified Potato Dextrose Agar as Growth Substrates for Fungi
Authors: Mislivec Philip B , Bruce Verneal R
Published: February 2020

Fifteen fungal species, all isolated from foods, were compared for their growth abilities on potato dextrose agar acidified to pH 3.5, and on nonacidified potato dextrose agar amended with 40 ppm Chlortetracycline hydrochloride. Comparisons were made at 16, 21, 26, 32, and 37°C. Of the 15 species, only Penicillium expansum exhibited better growth on the acidified medium than on the nonacidified antibiotic medium, while 9 species grew better on the nonacidified antibiotic medium. Five species grew equally well on either medium.
High-Performance and Gas-Liquid Chromatography of Methyl Parathion Formulations
Authors: Jackson Edwin R
Published: February 2020

Methyl parathion formulations (a synthetic sample, a technical material, and 6 emulsifiable concentrates) were analyzed by high-performance liquid chromatography (HPLC), gas-liquid chromatography (GLC), and infrared (IR) spectroscopy. The HPLC method used in ultraviolet detector and a Permaphase ODS column with a methanol-water mobile phase. The GLC method used an SE-30/OV-210 column and flame ionization detection. The IR spectrum was recorded at 8.16 μm. A synthetic sample formulated to contain 45.5% methyl parathion (analytical grade) was analyzed 8 times by each method. HPLC yielded an average value of 45.4%, GLC 45.9%, and IR 45.7%. Analyses of variance of this repeatability study showed that the differences between the GLC mean and both the theoretical value and the HPLC mean were small, but significant. Technical methyl parathion and 6 emulsifiable concentrates were analyzed in duplicate by each method. Variance calculations for each set of duplicates by each method indicate a high probability of difference in the methods. High results from the IR analysis are probably due to impurities in the technical material because analysis of the synthetic sample was satisfactory. The HPLC and GLC methods appear to be precise and will be studied collaboratively.
Collaborative Study of a Gas-Liquid Chromatographic Method for the Determination of Simazine
Authors: Hofberg Arthur H , Heinrichs Lee C , Gentry Gene A
Published: February 2020

A gas-liquid chromatographic method for the determination of simazine in a wettable powder formulation containing about 80% active ingredient was collaboratively studied, using a matched pair scheme. The samples were dissolved in dimethylformamide containing dioctyl phthalate as an internal standard, chromatographed on Carbowax 20M, and detected by using a flame ionization detector. Analysis of the 2 samples, based on peak height measurements, showed the following results: 1.5% overall coefficient of variation, 1.03% coefficient of variation for random error, and 0.23% systematic error. Sample A was an 80% powder formulation; Sample B was a 5% dilution of Sample A by the addition of inert material. The coefficients of variation were 1.20% for Sample A and 1.54% for Sample B. The larger variation in Sample B most likely resulted from nonuniform mixing during the dilution of Sample A. Since all collaborators used the same reference standard, the variation found in Sample A is more indicative of the variability of the method. The method has been adopted as official first action.
Rapid Screening Procedure for the Determination of Preservatives in Ground Beef: Sulfites, Benzoates, Sorbates, and Ascorbates
Authors: Karasz Albert B , Maxstadt John J , Reher Juergen , Decocco Frank
Published: February 2020

A procedure is described for the examination of large numbers of ground beef samples for the 4 most commonly used preservatives. A single sample solution is prepared and aliquots are taken for the various tests. Sulfite is determined colorimetrically with acid-bleached p-rosaniline. Ascorbic acid is titrated with 2,6-dichloroindophenol. Benzoic and sorbic acids are measured by ultraviolet absorption. Negative samples are rapidly sorted out in this procedure and positive samples are completed for quantitative determination of the preservative. Recoveries are 95% for sodium sulfite, 103% for sodium benzoate, 90% for potassium sorbate, and 81 % expected recovery for sodium ascorbate. The limit of detection is 0.005% for potassium sorbate, and 0.01% for the 3 other preservatives.
Collaborative Study of the Determination of Color in White Wines
Authors: Wildenradt Herb L , Caputi Arthur
Published: February 2020

A collaborative study was conducted on the determination of color in white wines by transreflectometry. The instrument used is designed to give a photometric response approximating the International Commission on Illumination CIE-z tristimulus function and provides transmittance values obtained from a 2.5 cm sample pathlength. Seven collaborators analyzed 13 samples (10 wines and 3 potassium dichromate solutions). Average transmittance values of the samples ranged from 75.34 to 87.56%. The standard deviations obtained in the study varied from 0.20 to 0.67 % transmittance. In view of the simplicity and reproducibility of the method, it has been adopted as official first action.
Colorimetric Assay of Reserpine in Formulations and Biological Fluids
Authors: Karawya Mohamed S , Sharaf Abdel-Aziz A , Diab Aly M
Published: February 2020

Two colorimetric methods are presented for determining reserpine. In the first method, an iron hydroxamate complex is formed through the ester group in position 16 in the reserpine molecule. The color is measured at 535 nm (0.5–6 mg/25 ml). This method is useful for routine and control analyses of reserpine formulations. In the second method the tertiary amino group of reserpine reacts with 2% citric acid in acetic anhydride to form a red-violet complex which is measured at 505 nm (5–400 μg/10 ml). This method could be useful in measuring trace amounts of reserpine present in biological fluids.
Gas-Liquid Chromatographic Determination of Diethylstilbestrol at Low Levels in Mixed Feeds
Authors: Einig Richard G
Published: February 2020

A gag-liquid chromatographic method for the determination of diethylstilbestrol (DES) at 2 ppb in mixed feeds and ingredients is presented. The DES is extracted into ethanol, the solvent is evaporated, and the residue is redissolved in chloroform. The extract is purified by washing the chloroform solution with carbonate buffer and transferring the DES to sodium hydroxide. The sodium hydroxide is washed with chloroform, the pH is adjusted to 10.3, and the DES is transferred to chloroform. The extract is derivatized with heptafiuorobutyric anhydride, chromatographed on an SE-30 glass column, and measured with a 3H electron capture detector. The method has been used for routine testing of a wide variety of feeds and ingredients.
Gas-Liquid Chromatographic Determination of Alachlor (2-Chloro-2′,6′-diethyh-N-(methoxymethyl)-acetanilide) Herbicide Residues in Corn and Soybeans
Authors: Ammann Barbara Dohman , Call Daniel J , Draayer Hans A
Published: February 2020

A method has been developed for the extraction and determination of alachlor (2-chloro-2′,6′-diethyl-N-(methoxymethyl)-acetanilide) residues in green corn and soybeans. Residues are extracted with acetonitrile and cleaned up on a Fiorisil column. The methylene chloride extract is sufficiently clean for electron capture gas-liquid chromatographic analysis and for verification by thin layer chromatography. Average recoveries of spiked samples (0.2 ppm) were 69 and 82% for corn and soybeans, respectively. This procedure could be useful for the detection of the parent compound in these crops soon after field application, but it does not detect metabolites.
An Improved Protein Parameter for Analytical Control of Cured Pork Production
Authors: Perrin Carrol H , Kelly Patrick C
Published: February 2020

Protein content expressed on a fat-free basis, PRF, has been proposed as a control of weight gain or meat content of cured pork. However, PRf is complicated to use, since it is a direct measure of meat content of the fat-free part of the sample. It is doubtful that this was the intention of the control. We propose the use of protein, fat-corrected basis, PRC, which is directly related to meat content of the sample as well as to weight gain. This would mean that conclusions about product quality could be made with greater certainty. PRC = PR + kF, where PR = % meat protein, F = % fat, and k is a constant.
Uses of Field Desorption Mass Spectrometry in the Pharmaceutical Industry
Authors: Brent David A
Published: February 2020

Field desorption (FD) is a gentle method of ionizing molecules from the solid state. The method is still in its infancy and remains more of an art than a science. Purines, pyrimidines, pteridines, and nucleosides represent some of the compound classes which are studied repeatedly in our laboratory. Often the primary information sought is the molecular weight. Many of these compounds are thermally unstable or nonvolatile. In these instances, FD mass spectrometry has proven to be quite helpful. Molecular weights are obtained in a short time, eliminating the need for more time-consuming derivatization or chemical degradation methods. FD has been applied to the study of drug metabolism and has shown great promise in determining polar metabolites, including direct analysis of glucuronide, sulfate, and amino acid conjugates. Some problems have been encountered in handling samples of biological origins. Salt impurities introduced by the separation procedure may interfere with the desorption process. Cluster ions and background noise make it difficult to assign molecular ions, and some compounds do not yield molecular ions with FD.
High-Pressure Liquid Chromatographic Analysis of Urea Herbicides in Foods
Authors: Lawrence James F
Published: February 2020

A method is described for the direct analysis of the urea herbicides linuron, monuron, diuron, chlorbromuron, fluometuron, chloroxuron, and fenuron in cabbage, corn, potatoes, turnip, and wheat at 0.01–1.0 ppm. The samples are extracted with acetone; the filtrate is partitioned with hexane-methylene chloride (1+1) followed by 2 other extractions with methylene chloride. The organic phases are dried and concentrated for column chromatographic cleanup on 2 % deactivated Florisil. The column fractions are evaporated just to dryness and redissolved in 10 ml isooctane for high-pressure liquid chromatography on a 25 cm silica gel (5 μm) column. Isopropanol in isooctane is the mobile phase, and compounds are measured by ultraviolet absorption at 254 nm. Recoveries are >80% in most cases. These results are confirmed by alkylation with sodium hydride-methyl iodide in dimethyl sulfoxide to form the methyl products which are analyzed by the same chromatographic system or by gas-liquid chromatography.
Reference Raman Spectra of Ten Phosphorus-Containing Pesticides
Authors: Nicholas Mark L , Powell David L , Williams Theodore R , Huff Sarah R
Published: February 2020

The Raman spectra of malathion, ethion, methyl parathion, parathion, EPN, O,O-diethyl-O-(2,4-dichlorophenyl) phosphorothioate, dichlorvos, mevinphos, tributyl phosphorotrithioite, and 2,4-dichlorobenzyltributylphosphonium chloride have been recorded. These spectra are presented, along with tables giving values for the frequencies.
Gas-Liquid Chromatographic Determination of Chlorphoxim Residues in Water and Fish by In-Block Methylation
Authors: Dale William E , Miles James W , Churchill Frederick C
Published: February 2020

A gas-liquid chromatographic method has been developed for the analysis of residues of chlorphoxim, 2-chloro-α-(((diethoxyphosphinothioyl)oxy)imino)-benzeneacetonitrile, in water and fish. The method is based on the in-block methylation of chlorphoxim with 0.01M trimethylanilinium hydroxide in methanol. The derivative, O,O-diethyl O-methyl phosphorothioate, was determined quantitatively by using a flame photometric detector specific for phosphorus. The in-block reaction is 70% efficient. Water samples were extracted with hexane; fish were extracted with methylene chloride and cleaned up on an acetonitrile-hexane partition column. Recoveries from water and fish samples spiked with chlorphoxim averaged 86.3 and 80.4%, respectively. Limits of detection were 10.0 ppb for 5 g samples of fish and 0.10 ppb for 300 ml water samples.
Gas-Liquid Chromatographic Determination of Azinphos Ethyl in Human Plasma and in Mouse Plasma, Tissue, and Fat
Authors: Stein Vincent B , Pittman Kenneth A
Published: February 2020

A new method for the determination of azinphos ethyl (O,O-diethyl-S-(4-oxo-1,2,3-benzotriazin-3(4H)-ylmethyl) phosphorodithioate) in human plasma and in mouse plasma, tissue, and fat has been developed. The method is based on extraction with benzene or hexane and cleanup of fat and tissue samples by a minicolumn containing Florisil and sodium sulfate. Azinphos ethyl is eluted from the column with 10% acetonitrile in benzene and is concentrated to an appropriate volume for gas-liquid chromatographic analysis, using a 63Ni electron capture detector and a glass column containing 3% OV-1 on Gas-Chrom Q. The method is sensitive to 0.005 ppm in human plasma, 0.01 ppm in mouse plasma, 0.08 ppm in mouse liver, 0.05 ppm in mouse brain, and 0.10 ppm in mouse fat. The limit of detection is 2 pg; mean recoveries ranged from 96 to 98%.
Gas-Liquid Chromatographic Determination of Chloramphenicol in Agricultural Crops
Authors: Sasaki Kumiko , Takeda Mitsuharu , Uchiyama Mitsuru
Published: February 2020

A method is presented for the gas-liquid chromatographic determination of chloramphenicol in agricultural crops. Chloramphenicol is extracted with ethyl acetate, cleaned up by silicic acid column chromatography, acetylated with acetic anhydride and pyridine, and then measured by gas-liquid chromatography with electron capture detection. Two stationary phases, DEGS + phosphoric acid and Reoplex 400, were used. The sensitivity was ca 8 ng (40% full scale deflection). The efficiency of the analytical method was evaluated by analyzing crops fortified with chloramphenicol. The average recovery ranged from 72% in unpolished rice to 86% in Chinese radishes.
Investigation and Identification of the Bromination Products of Dimethoxyamphetamines
Authors: Bailey Keith , Gagné Denise R , Pike Richard K
Published: February 2020

The qualitative analysis of the aromatic bromination products of the 6 isomeric dimethoxyamphetamines and their hydrochloride or hydrobromide salts is described. Their ultraviolet, mass, and proton magnetic resonance spectra are not sufficiently different for distinction but infrared spectra allow a positive identification to be made and reference spectra are provided for the bromination products of 2,4-, 2,5-, 2,6-, 4,5-, and 3,5-dimethoxyamphetamines. The application of gas-liquid and thin layer chromatography for the analysis of these products is discussed. The bromination of 2,3-dimethoxyamphetamine consistently gave mixtures which could not be separated satisfactorily; spectra are included for completeness of the comparison of products.
Gas Chromatographic Resolution of Organochlorine Insecticides on Mixed Phase Systems. II. OV-1/OV-25, OV-210/OV-25, and OV-225/OV-25 Systems
Authors: Yamato Yasuhiro , Suzuki Manabu , Watanabe Tadao
Published: February 2020

The resolution of organochlorine insecticides and related compounds on OV-1/OV-25, OV-210/OV-25, and OV-225/OV-25 mixed phase column systems was investigated. α-BHC, β-BHC, and γ-BHC (lindane) were resolved on the 0.5% OV-210/2% OV-25 system; α-BHC, β-BHC, and γ-BHC were separated on the 0.5% OV-225/2% OV-25 or 1% OV-1/2% OV-25 system. Heptachlor, heptachlor epoxide, aldrin, and endrin were resolved on the 0.5% OV-1/2% OV-25 system. Dieldrin was separated on the 5% OV-210/2% OV-25 or 5% OV-225/2% OV-25 system. DDT and its related compounds except p,p′-DDE and o,p′-DDE were resolved on the 5% OV-210/2% OV-25 or 0.5% OV-225/2% OV-25 system.
High-Pressure Liquid Chromatography of Benzo (a) pyrene and Benzo(ghi)perylene in Oil-Contaminated Shellfish
Authors: Guerrero Humberto , Biehl Edward R , Kenner Charles T
Published: February 2020

A high-pressure liquid chromatographic procedure is described for the determination of benzo (a) pyrene and benzo(ghi)perylene. These polynuclear aromatics are extracted with acetonitrile and partitioned into petroleum ether, the petroleum ether is removed, and the residue is saponified. The compounds are purified and isolated by passing the residue through a silica gel column and a high-pressure liquid chromatographic column, and detected by their ultraviolet absorption. Recoveries of standards through the procedure averaged 104%.
Simplex Optimization as a Step in Method Development
Authors: Dols Thomas J , Armbrecht Bernard H
Published: February 2020

In the course of method development, an optimization procedure should be performed before critical performance characteristics are measured. Interaction among the operational steps should be assumed to exist. The analysis of variance or the simplex procedures are designed to determine defined optimal responses. Other things being equal, the simplex method is more efficient in terms of the number of experiments required. This is due, in part, to the sequentially operated feedback strategy employed. Decisions are made according to 5 defined rules.
Rapid Determination of Butylated Hydroxyanisole, tert-Butylhydroquinone, and Propyl Gallate in Edible Oils by Electron Capture Gas-Liquid Chromatography
Authors: Page B Denis , Kennedy Barry P C
Published: February 2020

A rapid method is described for the determination of 2- and 3-tert-butyl-4-hydroxyanisole (2- and 3-BHA), tert-butylhydroquinone (TBHQ), and propyl gallate (PG) as their heptafluorobutyrates in edible oils. A solution of the oil in ether-benzene is treated with heptafluorobutyric anhydride (HFBA) in the presence of trimethylamine as catalyst. Excess HFBA is destroyed and a suitably diluted aliquot is analyzed by electron capture gas-liquid chromatography. An internal standard is added before derivatization to aid quantitation and identification of the antioxidants. Average recoveries from an oil spiked at 1, 5, 5, and 5 ppm TBHQ, 2-BHA, 3-BHA, and PG were 110, 105, 106, and 102%, respectively. At these low levels, however, some late-eluting peaks interfered. Butylated hydroxytoluene is not determined by this method.
Colorimetric Method for the Determination of Ethylene Dibromide Residues in Grains and Air
Authors: Rangaswamy Jois R , Vijayashankar Yadathora N , Muthu Mysore
Published: February 2020

A method based on the hydrolytic debromination of ethylene dibromide (EDB) in the presence of an oxidizing agent has been developed. Bromine liberated from inorganic bromide is used to brominate p-rosaniline. The intensity of the resulting violet-red bromo compound in chloroform is measured at 580 nm. The relationship between absorbance and concentration of EDB is linear in the range of 5–60 μg. The method is very sensitive and as little as 0.50 ppm unchanged EDB residue in a 20 g sample of fumigated grain and 1 ppm EDB in a 10 ml air sample can be detected.
Quantitative Determination of 4,4′-(Diazoamino)-dibenzenesulfonic Acid in FD&C Yellow No. 5 by Ion Exchange Chromatography
Authors: Fratz D Douglas
Published: February 2020

An ion exchange chromatographic procedure separates 4,4′-(diazoamino)-dibenzenesulfonic acid (DAADBSA) from FD&C Yellow No. 5 and DAADBSA is determined spectrophotometrically. Recoveries of DAADBSA added to FD&C Yellow No. 5 at levels of 0.01 to 0.4% ranged from 90 to 130%. DAADBSA was found in commercial samples of FD&C Yellow No. 5 in amounts ranging from 0.006 to 0.022%.
A Review of Sampling Plans and Collaboratively Studied Methods of Analysis for Aflatoxins
Authors: Schuller Pieter L , Horwitz William , Stoloff Leonard
Published: February 2020

Aflatoxins are the only food contaminants being monitored routinely on an international scale with methods operating at the order of magnitude of 10 μg/kg. At this concentration level, methods of analysis which can achieve coefficients of variation of 30–40% with recoveries of 70% or greater in interlaboratory collaborative studies can be considered eligible for referee status. In most cases, sample reproducibility is the variable limiting the reliability of methods of analysis. The inherent uncertainty of the identity of chromatographically separated entities requires the application of confirmatory tests to verify that the characteristic measured results from the presence of aflatoxin. The methods are also inoperable without a verification of the identity, purity, and concentration of the reference standards used. Screening methods which reliably eliminate negative samples from further consideration are indispensible for the practical operation of monitoring programs.
Analysis and Optimization of a Quantitative Organic Soil Neutralization Test for Disinfectants
Authors: Whitmore Elaine J , Miner Norman A
Published: February 2020

An analysis and optimization of a test to quantitatively assess the resistance of disinfectants to neutralization by organic soil is presented. The recommended method uses sterile, dry baker’s yeast as a standard organic soil, and 24-hr cultures of Staphylococcus aureus and Pseudomonas aeruginosa as test organisms. The test determines the maximum per cent (w/v) of organic soil which a disinfectant can tolerate and remain able to kill about 106 test organisms/ml in 10 min at 25°C. This per cent is defined as the organic soil neutralization number. The procedure offers several advantages over other organic soil capacity tests.
Differential Pulse Polarography of Cacodylate Injections
Authors: Holak Walter
Published: February 2020

A method was developed for the analysis of cacodylate injections, using differential pulse polarography for measuring As (III). The cacodylate molecule is decomposed to As(V) by heating with Mg(NO3)2 · 6H2O; As(V) is then chemically reduced to As (III) and polarographed in 1M HCl supporting electrolyte. The method of standard addition is used for quantitation. Recoveries based on the analysis of synthetic cacodylic acid solutions containing approximately 9 mg arsenic/ml ranged from 99.1 to 101.7%.
Collaborative Study of a Mineral Oil Method for the Extraction of Light Filth from Ground Paprika
Authors: Thrasher Joel J , Gentry Rose
Published: February 2020

An official first action method for the extraction of light filth from spices, 44.A03— 44.A05, was modified for the analyses of ground paprika. The sample is extracted with isopropanol and light filth is isolated from 40% isopropanol with mineral oil. Eight collaborators analyzed 4 paprika samples, 2 by the official method and 2 by the proposed method. Average recoveries of added elytral squares were 97 and 66%, respectively, for the proposed and official methods. Recoveries of added rodent hairs were 94 and 61%, respectively. The method has been adopted as official first action for the extraction of light filth from ground paprika.
Automated Determination of Thiamine and Riboflavin in Various Foods
Authors: Pelletier Omer , Madère Rene
Published: February 2020

Thiamine and riboflavin were determined in various foods by automated analysis. Foods hydrolyzed before diastase digestion usually yielded more of both vitamins, except for lower thiamine values in fish and nonprocessed meats. Loss of both vitamins during the separation of insoluble matter from certain fruits was prevented by adding ethylene glycol monomethyl ether. Extraction in the presence of cysteine gave higher thiamine values in samples dehydrated with heat such as milk and potatoes. Recoveries of flavin adenine dinucleotide (FAD) and thiamine pyrophosphate (TPP) were complete with the automated methods, but recoveries of FAD were less satisfactory with AOAC method 43.039—43.042. Riboflavin values by the AOAC method agreed with those by the automated method in cereals, meats, and dairy products but were slightly higher in other foods. The automated method appears more specific because it directly measures total riboflavin, including that derived quantitatively from FAD and flavin mononucleotide (FMN), while in the AOAC method the natural forms are hydrolyzed to FMN which is measured against a riboflavin standard. Much of the interfering fluorescent compounds are separated from riboflavin in the flow-through automated system. In general, variations from day to day were quite acceptable by the automated methods but often unacceptable by the AOAC riboflavin method.