bluuebunny/crossref_metadata_2025 huggingface dataset:
High Pressure Liquid Chromatography with Ultraviolet Absorbance or Fluorescence Detection of Carbaryl in Potato and Corn
Authors: Lawrence James F , Leduc Raymonde
Published: February 2020

Carbaryl (1 - naphthyl -N - methylcarbamate) was extracted from corn and potato with acetone. The acetone extract was partitioned into methylene chloride-hexane and concentrated for cleanup on a 5 % water-deactivated Florisil column. The fraction containing the carbamate was subjected to high pressure liquid chromatographic (HPLC) analysis on a 25 cm LiChrosorb Si60 (5 >m) column (2.2 mm id) by various means. First, the pesticide was analyzed directly with ultraviolet (UV) absorption detection at 254 nm and a mobile phase of trimethylpentane- isopropanol (96+4). After this, a fluorescent derivative was prepared, using dansyl chloride (5-dimethyIaminonaphthalene- 1-sulfonyl chloride), and analyzed by HPLC, using trimethylpentane-dioxane ( 9 5 + 5 ) as the mobile phase, with both UV absorption (254 nm) and fluorescence (excitation 365 nm, emission >400 nm) detection. The response/ng for the dansyl derivative with fluorescence detection was 1.3 times greater than that for UV detection and 8 times more sensitive than direct UV detection of the carbamate. About 10 ppb carbaryl could be detected after derivatization in the foods studied; for direct analysis, 30—50 ppb could be detected at a 2:1 signal:noise ratio. Recoveries at 0.1 ppm averaged 9 0% by direct analysis compared with 7 8% after derivatization.
Bioavailability, in vitro Solubility, and Physical and Chemical Properties of Elemental Iron Powders
Authors: Motzok Ilary , Verma Ramesh S , Chen Shy-Show , Hasper Jaroslava , Hancock Ronald G V , Ross Henry U
Published: February 2020

The relative biological value (RBV) for rats of the iron from 7 elemental iron powders (produced by electrolysis, reduction with hydrogen (H2), carbon monoxide (CO), and desiccated ammonia (NH3), and carbonyl process) were compared with the in vitro solubility of the iron powders in 0.2% HC1 (w/v, ca 0.05/V) for periods of 5 to 90 min. The values obtained for per cent solubility in 10 min were within the fiducial limits of the individual RBVs of 6 iron samples; the exception was one preparation of carbonyl iron whose solubility, but not RBV, was as high as that of electrolytic iron. These data indicate that dissolution rates were good predictors of bioavailability of some types of elemental iron powders. There was good agreement between specific surface areas and particle size distributions of discrete fractions containing fine particles of comparable sizes (7—10 μm) of electrolytic, H2- and CO-reduced iron, and whole preparations of carbonyl iron, but these measurements were not satisfactory criteria for predicting bioavailability. SLOWPOKE neutron activation analysis of the iron powders showed that the carbonyl iron samples contained the lowest concentrations of elements producing short- and long-lived radioisotopes (24Na, 27Mg, 49Ca, 38Cl, 28A1, 66Cu, 56Mn, 52V, 101Mo, 51Cr, 122Sb, and 60Co) with the exception that the Mo content of one preparation was ca 2 times higher than in the other iron samples. Electrolytic iron contained higher levels of Na, Ca, Al, Cu, Mn, V, Sb, and Co than carbonyl iron. H2-, CO-, and NH3-reduced iron samples contained the highest levels of impurities, notably Na, Mg, Ca, CI, Al, Cu, Mn, V, and Cr.
Semi automated Method for Determining Ferrous Sulfate in Pharmaceuticals: Collaborative Study
Authors: Mccullen Percy A
Published: February 2020

A semiautomated colorimetric method is described for determining ferrous sulfate in tablets, capsules, and elixirs. The method involves the formation of an orange-red complex between 1,10-phenanthroline and ferrous ion. Collaborators were supplied with 3 solid composites and one liquid sample. Two of the solid composites were prepared from commercial tablets of different dosage and one from commercial timed-release capsules; the fourth sample was an elixir. The results of the automated analyses for ferrous sulfate agreed well with those of the applicable USP method. No interference was found from ferric iron or from the red and green coloring used on coated tablets. The method has been adopted as official first action.
Liquid Chromatographic Determination of Lasalocid in Premixes
Authors: Hagel Robert B
Published: February 2020

A high pressure liquid chromatographic (HPLC) method has been developed to determine lasalocid in premixes. The method is simple and rapid, requiring an extraction of the drug and separation of insoluble material before HPLC. Elution times are typically <10 min per sample. The average recoveries for lasalocid at the 16.5 and 50% levels were 100.2±2 and 100.0±2%, respectively. The precision of the method (coefficient of variation = 0.02) compares favorably with that of the approved bioassay (coefficient of variation = 0.06).
Colorimetric Determination of Arprinocid in Feed
Authors: Fink David W , Martin Kobert P , Pivnichny James V , Shim Jung-Sook K
Published: February 2020

An analytical method has been developed for the determination of arprinocid (9-(2-chloro- fluorophenylmethyl) -9ff-purin-6-amine) in feed, based upon measurement of the absorbance of the diazo chromophore formed from product of zinc reduction of the drug in acidic solution. The analyte is extracted from the feed into chloroform in the presence of a pH 7 phosphate buffer and isolated by adsorption chromatography on alumina, followed by partitioning between hexane and 0.15M HC1. The reduction product in the aqueous phase is then treated for colorimetric measurement. This procedure has been applied to determining 0.0010-0.0080% arprinocid in feed with precision of <5% relative standard deviation near the middle of this concentration range. Of 32 feed additives examined, only zoalene and sulfamethazine were serious interferences. study and discussion of several factors, e.g., reaction time, pH, and amount of zinc metal, that affect the analytical reactions are also included.
Determination of Neomycin Residues in Eggs and Stability of Residues After Cooking
Authors: Katz Stanley E , Levine Priscilla R
Published: February 2020

The procedure for neomycin residues used a surfactant to improve extraction, a centrifuge step to eliminate solids that interfere with the diffusion of the antibiotic, and a heat treatment to destroy interfering lysozyme activity. The use of Bacillus stearothermophilus and a 65°C incubation yielded a rapid assay with a sensitivity of 0.2 μg neomycin activity/g egg. Frying eggs caused little or no loss of activity, poaching resulted in 25% loss, and soft boiling and hard boiling caused little or no loss of applied activity. Neomycin residues in eggs were quite stable to normal egg preparation procedures.
Control of Hormone Treatment in Animals and Residues in Meat—Regulatory Aspects and Approaches in Methodology
Authors: Karg Heinrich , Vogt Karl
Published: February 2020

Although the benefit of using anabolic hormones for fattening purposes under specific situations in animal husbandry (for instance, veal production) has been acknowledged in European countries, the regulatory consequences were quite different from those in the United States. With the exception of the United Kingdom, there were no approvals to use estrogens for other than distinct veterinary purposes. Hence the methodological approaches were rather to control the illegal treatments and imports. One measure is the uterus weight bioassay. Furthermore morphological parameters (prostate test) and estrogen determinations by thin layer chromatography in urine (also from the bladder) were proposed for detection of treated animals. Radioimmunoassays are in development and considered sensitive enough for residue studies in carcasses, perhaps applicable in combination with high pressure liquid chromatography. The re-evaluation of the regulatory situation is in progress in France and Germany and under consideration in the United Kingdom. Guidelines may be the recommendations of the FAO/WHO Symposium 1975 in Rome on anabolic agents in animal production indicating the variety of risks due to different compounds in question and preference to those with low oral activity and defined bio-degradation.
Use of Radioimmunoassay for Monitoring Hormonal Residues in Edible Animal Products
Authors: Hoffmann Bernd
Published: February 2020

Radioimmunoassay (RIA) is valuable for sensitive and specific routine measurements of hormones in body fluids. The method is also applicable to determine tissue levels of hormones which, according to tracer studies and depending on the compound, are scattered in the lower ng and pg/g range. For practical assay application it must be decided whether the parent compound or a major metabolite should be measured. Both toxicological and practical regulatory aspects have to be considered, but in any case knowledge of the metabolic profile of the compounds is necessary, especially since the specificity of the RIA group analysis is limited. When applying extraction and purification steps, differences between compounds and between tissues have to be considered; generally more difficulties are encountered than with plasma. Validation of the method should first demonstrate no unspccific interference with the antigen-antibody reaction; then the other reliability criteria have to be established. So far RIAs for the quantitation of estrogens, testosterone, progesterone, and trienbolone—a synthetic androgen—in various bovine tissue samples have been developed. The lower limit of sensitivity ranges between 10 and 70 pg/g. Quantitation of physiological levels of testosterone and progesterone is possible, but there are still some problems with estrogens.
Reverse Phase High Pressure Liquid Chromatographic Determination of Aflatoxins in Foods
Authors: Beebe Roberta M
Published: February 2020

A method for determining aflatoxins by high pressure liquid chromatography (HPLC) with fluorescence detection after CB extraction and cleanup has been applied to various foods. Recoveries at 1—15 ppb levels from green coffee and peanut butter were 72-85 and 74—104%, respectively. Precision of the method has been tested for peanut butter. Other products to which the method has been successfully applied include tree nuts, seeds, grains, chocolate-covered peanut butter candy, and roasted, salted-in- shell peanuts. High levels of aflatoxins found in several samples of nuts by this method have been verified by the official thin layer chromatographic (TLC) method. The advantages of this HPLC method are speed, precision, sensitivity, selectivity, and immediate chemical confirmation of aflatoxins B1 and G1. None of the products analyzed required special cleanup procedures. Preparative-scale HPLC was used to isolate purified B1 for toxicity testing.
Microcrystalline Identification Test of Some Amphetamines and Hydrochlorothiazide: Collaborative Study
Authors: Auerbach Leonora
Published: February 2020

A previously described procedure for the identification of methamphetamine, dl-deoxyephedrine, dextroamphetamine, and amphetamine and a new procedure for hydrochlorothiazide identification have been subjected to collaborative study. The method for the amphetamines depends upon their volatilization from a strongly basic solution into a hanging drop containing gold chloride and the formation of characteristic crystals. The hydrochlorothiazide method is direct: the I2-KI solution is added to an alkaline solution of hydrochlorothiazide to cause the deposition of characteristic crystals. Of the 40 unknown drug dosage form powders supplied to 10 collaborators, 39 were correctly identified. The results indicate that the amphetamine procedure is capable of distinguishing between methampetamine and dl-deoxyephedrine. The age of the gold chloride reagent is important in these tests. The official final action tests for dl-deoxyephedrine and methampetamine were modified and Table 36:04 has been revised to reflect these changes. The hydrochlorothiazide test has been adopted as official first action and added to Table 36:05.
Efficient Concentration Procedure for Recovery of Nanogram Amounts of Hexachlorocyclohexane Isomers
Authors: Malaiyandi Murugan
Published: February 2020

Attempts to concentrate hexane solutions containing ca 1-50 pg/ml α-, β-, γ-, and δ-isomers of hexachlorocyclohexane (HCH) in Kuderna- Danish (K-D) evaporators gave inconsistent recoveries, ranging from 45.0 to 98.1%. This disadvantage has been overcome by adding a built-in distillation trap below the Vigreauxbubble condensing system of the Snyder column. Using the K-D evaporator with the modified Snyder column for concentrating 5 replicate solutions with 6 different concentrations of mixtures of HCH, mean % recoveries (standard deviation) of 92.4 (±5.5), 100.4 (±6.0) , 99.0 (±7.2) , and 79.7 (±9.7) were obtained for the α-, β-, γ-, and δ-isomers, respectively, indicating excellent performance efficiency of the system. A low F-ratio was obtained from statistical analysis of recovery data for the 4 isomers, denoting insignificant differences between concentrations for each isomer. Furthermore, the method has been evaluated by analyzing hexane samples fortified with isomeric mixtures of HCH by an independent analyst. For 3 different levels of fortification, mean recoveries (%) were 87.9, 94.9, 90.1, and 72.4 for the α-, β-, γ-, and δ-isomers, respectively.
Selective Colorimetric Determination of Linuron in Soils in the Presence of Metabolites
Authors: Friestad Håkon O
Published: February 2020

Intact residues of linuron in soils are determined by dichloromethane extraction, cleanup of the extract by partition between dimethyl sulfoxide and petroleum ether, acid hydrolysis in closed test tubes, and automated colorimetry of the resulting 3,4-dichloroaniline. Low blank values for soil types of widely varying characteristics make untreated controls superfluous. The detectability limit is approximately 0.1 mg/kg. Recovery is 88—106% and the standard deviation in the 0.5—1.0 mg/kg range is less than 0.1 mg/kg. Metabolites will not influence the analysis unless they are present in considerably higher amounts than the parent compound.
Gas-Liquid Chromatographic Method for Determining Fentin in Fentin-Maneb Preparations: CIPAC Interlaboratory Study
Authors: Basters John , Martijn Albertus , Van Der Molen Thomas , Pasma Piet , Rabenort Barend , Van Rossum Bram , Smink Jaap
Published: February 2020

A gas-liquid chromatographic (GLC) method is described for determining fentin acetate and fentin hydroxide in formulations in the presence of maneb. Triphenyltin acetate or hydroxide is converted to butyltriphenyltin by the Grignard reaction; the product is determined by GLC, using flame ionization or thermal conductivity detection, a column containing 5% SE-30 on Chromosorb W (HP) or Gas-Chrom Q, and docosane as the internal standard. Fifteen laboratories tested the method on 6 samples. The estimated repeatabilities expressed as coefficients of variation, ranged from 0.8 to 1.4% and the estimated reproducibilities from 1.3 to 1.7%.
Determination of Ethylene Dibromide in Fortified Soils by Molecular Emission Cavity Analysis Using a Modified Extraction Process
Authors: Abdel-Kader Mohammed H K , Peach Michael E , Stiles David A
Published: February 2020

A method is described for the determination of small quantities of ethylene dibromide (EDB) in soils. The EDB is distilled from an aqueous slurry of the fortified soil into a cooled mixture of acetone-isooctane, which is then decomposed in a Schoniger flask. The resultant hydrogen bromide is injected into an indium-lined cavity of a molecular emission cavity analysis instrument and is quantitated from the intensity of the InBr emission (λmax = 376 nm). The detection limit of EDB is less than 0.5 ppm. Recovery of EDB added to soils at 0.5—10 ppm was greater than 96%.
Minicolumn Detection Method Applied to Almonds: Collaborative Study
Authors: Stanley George I , Diprossimo Vincent P , Koontz Anna C
Published: February 2020

The minicolumn screening method for aflatoxins was collaboratively tested on naturally contaminated almonds. The nuts were extracted, and the extract was cleaned up and applied to a Velasco-type minicolumn. This permits the detection of total anatoxins (B1, B2, G1, G2) as a fluorescent band on the Florisil layer of the column. The results of 20 collaborators are presented. Samples containing 0, 2, 5, 10, and 25 ng aflatoxin/g were analyzed. Ninety-six per cent of the samples containing 5—25 ng total aflatoxins/g and 83% of the negative samples were correctly identified. The method has been adopted as official first action for detection of total aflatoxin levels of ≥5 ng/g.
Instability of PR Toxin in Blue Cheese
Authors: Scott Peter M , Kanhere Shriniwas R
Published: February 2020

PR toxin was unstable in solvent extracts of blue cheese and in strongly acidic solutions. However, it was appreciably stable over a 2.5 hr period in moderately acidic methanol-water extracts (pH 2—3) of blue cheese. Using this extraction mixture, it was determined that PR toxin was not stable in blue cheese itself. PR toxin reacted with model neutral and basic amino acids and the formation of PR imine from PR toxin in the presence of blue cheese was demonstrated. While PR imine added to blue cheese could be recovered on analysis after 5 min, over a 2—5 day period it too was unstable in the cheese.
Gas-Liquid Chromatographic Determination of Nicotine Contained on Cambridge Filter Pads: Collaborative Study
Authors: Wagner John R , Thaggard Neil A
Published: February 2020

Nicotine was extracted from Cambridge filter pads with 10 mL 2-propanol containing 1 mg anethole/mL as the internal standard. Five standards ranging from 0.25 to 1.25 mg nicotine/ mL were injected into a 6 ft × 1/8 in. column packed with 2% KOH and 10% Carbowax 20M on 45—60 mesh diatomaceous earth to standardize the procedure. The injection port and detector were operated at 200—250°C, the column was operated at 165°C, and the helium flow was adjusted to ca 40 mL/min. Data were taken with systems giving resolutions of 1 count/mv-sec. Results from 16 laboratories gave standard deviations ranging from 0.02 to 0.06 mg nicotine/mL. Suggested improvements were incorporated into a second study, and 13 laboratories analyzed 5 paired samples; standard deviations ranged from 0.02 to 0.03 mg nicotine/mL. The method has been adopted as official first action.
Colorimetric Determination of Carvone in Volatile Oils in the Presence of Menthone and Pulegone
Authors: Karawya Mohamed S , Hifnawy Mohamed S , El-Hawary Seham S
Published: February 2020

Carvone, menthone, and pulegone in volatile oils are determined by measuring at 370 nm the color obtained by their reaction with 3,5-dinitrobenzoic acid (DNBA) or m-dinitrobenzene (DNB). The DNBA method is sensitive to 50—1500 μg carvone or pulegone/10 mL and to 500-1500 μg menthone/10 mL. The DNB method is as sensitive to carvone and menthone as is the DNBA method, but it is less sensitive to pulegone (300—1500 μg/10 mL). Either carvone or pulegone in the presence of menthone can be determined by using the DNBA method at concentrations less than 500 μg menthone/10 mL. Carvone can also be estimated by the DNB method without pulegone and menthone interference when these constituents are present at levels less than 300 and 500 μg/10 mL, respectively. Other ketonic constituents, piperitone, methyl heptenone, and ionone, did not respond to the color reaction except at concentrations above 750 μg/10 mL. The method was successfully used for the estimation of carvone in oils of Mentha viridis, M. crispa, caraway, and dill.
High Pressure Liquid Chromatographic Determination of Furazolidone in Turkey Tissue
Authors: Hoener Betty-Ann , Lee Gloria , Lundergan William
Published: February 2020

A high pressure liquid chromatographic method for determining furazolidone in turkey tissue has been developed. Tissues are ground with methanol and centrifuged. For lower levels of furazolidone, 2—40 ppb, the supernate is evaporated to dryness and redissolved before it is injected onto the liquid chromatographic column. Using a reverse phase column and an ultraviolet absorption detector set at 365 nm, the assay is linear over the concentration range 2—400 ppb with a coefficient of variation of <4%. Average recovery from fortified tissues was 96% with a coefficient of variation of 6% at the 50-400 ppb level, and 105% with a coefficient of variation of 11% at the 2—40 ppb level.
High Pressure Liquid Chromatographic Determination of the Five Major Alkaloids in Papaver somniferum L. and Thebaine in Papaver bracteatum Lindl. Capsular Tissue
Authors: Vincent Phillip G , Engelke Beatriz Ferreira
Published: February 2020

A high pressure liquid chromatographic isocratic procedure is described for determining and quantitating the 5 major alkaloids narcotine, papaverine, thebaine, codeine, and morphine in Papaver somniferum L. and thebaine in Papaver bracteatum Lindl. Other papaveraceous alkaloids, including salutaridine, oripavine, laudanosine, isothebaine, cryptopine, alpinigenine, narceine, protopine, and gnoscopine, were also quantitated. The values for morphine, codeine, and thebaine in P. somniferum were in agreement within 5—9% with values obtained by the United Nations Narcotics Laboratory by other methods. In contrast to previously reported procedures, the advantage of this method is that no precolumn or other purification other than solvent extraction of the capsular tissue is necessary. Isocratic chromatography alone on a single column resolved the 5 major alkaloids.
High Pressure Liquid Chromatographic Determination of Saccharides in Corn Sirups: Collaborative Study
Authors: Engel C Earl , Olinger Philip M
Published: February 2020

A liquid chromatographic method for quantitative analysis of saccharides in corn sirup was investigated. Fructose, glucose, and related saccharides are separated on an Aminex 50W-X4, calcium form, cation exchange column or, alternatively, on an Aminex Q15-S, calcium form, cation exchange column. Water is the solvent. All carbohydrate components in the sirup elute from the column, permitting normalized computation vs. synthetically prepared standards. The corn sirup samples are diluted to an approximate dry substance and injected directly into the chromatograph. When required, interfering ionic material is removed with the aid of a mixed strong acid-weak base ion exchange resin. The reproducibility and repeatability coefficients of variation for fructose (on samples ranging from 15 to 90% fructose) are 0.9 and 0.3%, respectively. The reproducibility and repeatability coefficients of variation for glucose (on samples ranging from 8 to 50% glucose) are 1.4 and 0.5%, respectively. The method has been adopted as official first action.
Thin Layer Chromatographic Determination of Ctrinin
Authors: Chalam Ramaswamy V , Stahr Henry M
Published: February 2020

A thin layer chromatographic (TLC) method is described for the determination of citrinin in feeds. Citrinin is extracted from feed with methanol and water, the mixture is made alkaline with 10% sodium carbonate, and the aqueous solution is filtered and extracted with chloroform to remove most of the interfering materials. The aqueous layer is acidified with 2N HCl and extracted with chloroform. The chloroform extract is concentrated and spotted on a thin layer chromatographic (TLC) plate which is developed in chloroform-acetoneethanol- water (60+40+10+1). The citrinin is viewed under ultraviolet light after TLC. Either visual or fiuorodensitometric quantitation is used. Recoveries of citrinin from various feed samples spiked at levels of 2.0–5 μg/g were 75–92%. The proposed method can detect 0.5 μg/g feed, including corn, silage, ready mixed feeds, and feed pellets.
Gas-Liquid Chromatographic Determination of 7-Nonalactone in Alcoholic Flavors and Beverages
Authors: Dyer Randolph H , Martin Glenn E
Published: February 2020

A gas-liquid chromatographic (CLC) method was developed for the quantitative determination of γ-nonalactone in alcoholic flavors and beverages. Other common lactones (heptalactone, octalactone, decalactone, undecalactone, and dodecalactone) were separated using the GLC procedure, and mass spectrometric confirmation of these compounds and γ-nonalactone was carried out. In addition, fresh coconuts were analγzed; no γ-nonalactone was found at a detection limit of 0.5 mg/L. Thirty-six samples of flavors and beverages were analyzed for γ-nonalactone; the results ranged from 5750 to <0.5 mg/L.
Determination of Virginiamycin in Feeds
Authors: Ragheb Hussein S , Black Lisa J , Waisner Debra L
Published: February 2020

Virginiamycin was extracted from the feed by ethanol-pH 2.5 phosphate buffer (1+l). The pH during extraction was adjusted (when necessary) to between 4 and 5. Sample dilutions and the standard dose response line were prepared to contain ethanol-pH 6 phosphate buffer (2+8), and the test organism was Sarcina lutea. Three feeds (a poultry ration, a swine finishing ration, and a swine starter ration) showed virginiamycin recovery of 88.8–108.9% when standard solutions were added at concentrations of 4.54–90.8 g/ton. The coefficient of variation (4–20%) was larger for low potency feeds (10 g/ton) compared to the higher feeds (100 g/ton). Similarly, excellent recovery was obtained when the swine starter feed was fortified by a commercial premix. Amprolium, roxarsone, and monensin can be present at 20 times the concentration of virginiamycin with little or no interference in the antibiotic determination. Lasalocid at 10 times the concentration of virginiamycin caused a slightly positive bias (recovery, 107.4%).
Modification of the Neutral-Detergent Fiber Procedure for Cereals and Vegetables by Using α-Amylase
Authors: Mcqueen Ralph E , Nicholson James W G
Published: February 2020

Samples with a high starch content that were incubated at 40°C overnight (12-18 hr) in pH 7 buffer with bacterial α-amylase before determination of their neutral-detergent fiber (NDF) contents were easier to filter and had lower estimates of NDF and hemicellulose than when the conventional procedure was used. At neutral pH, bacterial a-amylase was more effective in this role than 2 common fungal amylase preparations. Pretreatment with pepsin at pH 1.8 also reduced the estimates of NDF content but some samples still proved difficult to filter. Bacterial α-amylase that was added during the initial step of the ccnventional procedure exhibited some activity even after boiling in neutral-detergent reagent for 30 min and promoted rapid filtration of the samples, but led to estimates that were higher than those obtained following overnight incubation at 40°C. The reported modification of incubating samples overnight with α-amylase promotes rapid filtration, and thereby gives more accurate NDF estimates and less analytical variation for samples of cereal grains and vegetables that have a high starch content.
High Pressure Liquid Chromatographic Separation of Rotenoids from Plant Extracts
Authors: Moring Stephen E , McChesney James D
Published: February 2020

The concomitant isolation, identification, and quantitative determination of rotenoids by high pressure liquid chromatography and ultraviolet and mass spectral analyses is presented. Plant samples are extracted with chloroform-methanol, subjected to a combination of solvent partitioning and silica gel open column chromatographic cleanup, and then chromatographed by HPLC reverse phase techniques. Concentrations of rotenone and deguelin are reported for Tephrosia virginiana (L.) Pers. and Amorpha canescens Persh.
Mass Spectrometric Identification and Gas-Liquid Chromatographic Determination of 2-Chloroethyl Esters of Fatty Acids in Spices and Foods
Authors: Heikes David L , Griffitt Kenneth R
Published: February 2020

The 2-chloroethyl esters of 5 fatty acids have been identified in spice and food samples by gas-liquid chromatography-mass spectrometry (GLC/MS). Twenty-four spice samples were analyzed for the 2-chloroethyl esters of fatty acids by AOAC official multiple residue pesticide procedures using CLC with microcoulometric detection. The esters of capric, lauric, myristic, palmitic, and linoleic acids have been identified at levels up to 1400 ppm. 2-Chloroethyl linoleate was the most abundant ester in all samples. Several foods analyzed by the same procedures showed levels of 2-chloroethyl linoleate as high as 35 ppm. Recoveries from fortified samples ranged from 84 to 98% for the various esters. A method using an acid-catalyzed esterification reaction was developed to rapidly determine the fatty acid content of these spices. CLC analysis with microcoulometric detection was used. Recoveries from fortified samples ranged from 92 to 110%. After 2 spice samples found to be free of 2-chloroethyl esters were fumigated with ethylene oxide, the level of 2-chloroethyl linoleate reached 77 ppm. All levels of 2-chloroethyl esters were confirmed by GLC/MS.
Collaborative Studies on Cytogenetic and Dominant Lethal Assays
Authors: Sheu Ching-Ju W
Published: February 2020

Two ire vivo cytogenetic studies and one dominant lethal study were jointly conducted by members of government, academic, industrial, and independent commercial laboratories between 1970 and 1975 to determine the validity and reproducibility of the techniques. The cytogenetic studies consisted of preparations and analyses of bone marrow cells from male rats for chromosome abnormalities. In the first study, participants from 4 laboratories jointly prepared slides at a Food and Drug Administration (FDA) laboratory according to a prescribed procedure and independently analyzed the slides in their own laboratories. In the second study involving 6 laboratories, a workshop was held at Dow Chemical Co. to reduce scoring differences and to develop a joint protocol. All participants then independently performed the exact procedure in their own laboratories, using animals from a common source. In the dominant lethal study involving 6 laboratories, a workshop was held at the FDA to discuss protocol and to practice the technique. All participants then independently conducted the study in their own laboratories using rats and test chemicals from common sources. In all 3 studies, significant interlaboratory variability existed, and the differences varied with the parameters analyzed.
Review of in vitro Test Systems Using DNA Damage and Repair for Screening of Chemical Carcinogens
Authors: Williams Gary M
Published: February 2020

Chemical carcinogens are mechanistically classified as genotoxic which interact directly with DNA, and epigenetic which cause chronic tissue injury, hormonal imbalance, and promotional effects. This review evaluates in vitro tests for their contribution to a battery for identifying genotoxic chemical carcinogens. In addition to bacterial mutagenic assays, nonspecific DNA damage/repair tests are recommended for screening chemicals, in particular the hepatocyte primary culture/DNA repair test.
Intercomparison Study on the Determination of Single Administration Toxicity in Rats
Authors: Hunter William J , Lingk W , Recht P
Published: February 2020

In 1977, the Commission of the European Communities initiated an intercomparison study to determine the single administration oral LD50 value in rats of each of 5 chemicals with the aims of comparing experimentation technologies, determining the degree of variation in the results and the various parameters used to establish the LD50 value, and establishing a common protocol for the determination of the LD50 value. Sixty-five laboratories in 8 countries took part in the first study. The significant variation in protocol may have led to the large interlaboratory variation observed in the results. Therefore, participating laboratories carried out a second study using a common protocol, preceded by a pilot study. A total of 100 laboratories in 13 countries participated. A majority of results of the second study are currently being analyzed, and the indications are that the interlaboratory variation has been significantly reduced.
Comparison of Studies on Saccharin and Sodium Nitrite
Authors: Taylor Jean M , Morgenroth Victor H
Published: February 2020

A review of long term animal studies of saccharin and sodium nitrite was undertaken to assess the effect of variability of selected protocol elements on the results obtained. These elements were divided into 4 general categories: design, including selection of test animals, basal diet, dosage form and doses of test substance, route of administration, and duration of exposure; observations, including gross observations during life and at necropsy, clinical tests, and histopathology; performance, including conduct of the test and animal husbandry; and analytical procedures, including chemical and statistical analyses. Because many of the protocol elements are not fully discussed in study reports, it was often impossible to determine what actually had been done. The review of various saccharin studies suggests that bladder tumors resulted following in utero exposure. In utero exposure with sodium nitrite did not appear to cause reticuloendothelial changes. The numerous variations in protocol elements in the nitrite studies precluded identification of a prime element responsible for the variation in reticuloendothelial changes observed. It can be concluded from this review that achievement of reproducibility in long term studies requires minimal variation of protocol elements for the new study.
Comparison of Stomacher and Waring Blendor for Homogenizing Foods to be Examined for Clostridium perfringens
Authors: Harmon Stanley M , Kautter Donald A
Published: February 2020

The Colworth Stomacher Model 400 homogenizer was compared with the Waring Blendor for preparing food homogenates to be examined for Clostridium perfringens. Forty-eight samples representing 6 different food types were inoculated with C. perfringens and examined by the AOAC official first action method for enumeration of C. perfringens in foods. Identical paired specimens of each food type were blended with the 2 devices, and plate counts were made as specified in the official first action method. The effects of frozen storage on plate counts were determined by examining 24 food samples that had been stored for 3 days at —68°C and homogenized by both devices. Results of a statistical analysis of the experimental data indicated no significant difference overall (P > 0.05) in the plate counts of homogenates prepared with the Waring Blendor or the Stomacher 400, either before or after frozen storage of the food samples. However, the overall plate count average of the 48 samples was slightly higher with the Waring Blendor than with the Stomacher 400 homogenizer.
Extraction, Cleanup, and Quantitative Determination of Aflatoxins B1 and M1 in Beef Liver
Authors: Trucksess Mary W , Stoloff Leonard
Published: February 2020

A method for the determination of aflatoxin Bx in eggs was applicable for aflatoxin B1 in liver, but ineffective for aflatoxin Mx in liver because of poor recovery of added aflatoxin and interferences in thin layer chromatography. The method was modified by the addition of citric acid to the extracting solvent and ammonium sulfate to the extract solution for removing protein. The elution system for silica gel column cleanup was also changed by substituting methanol for acetone, and adding a step for confirmation of aflatoxin M1 identity. The method has been used successfully for survey and research on aflatoxin residues in animal tissues.
Aflatoxin Variation Among Corn Samples with Varying Ratios of Aspergillus flarws-Inoculated/Noninoculated Kernels
Authors: Lillehoj Eivind B , Calvert Oscar H , Kwolek William F , Zuber Marcus S
Published: February 2020

Aflatoxin levels and physical properties of corn kernels inoculated with Aspergillus flavus during development and noninoculated kernels were compared in samples with various proportions of the 2 kernel types. The relationship between mean toxin levels and associated standard deviations of 5 samples demonstrated a linear association from the lowest toxin in noninoculated corn through a mixture of 60% inoculated/40% noninoculated. However, at the highest toxin level in the 100% inoculated material, a reduction in sample variation was observed. Examination of individual kernel weights showed that inoculated kernels were distinctly lighter than noninoculated seed. A uniform grinding procedure of the samples yielded heterogeneous particle sizes based on the starting corn. The large particle fraction (>500 μm) decreased from 100% noninoculated kernels through the mixtures to the 100% inoculated seed; particles below 150 >m were most abundant in the ground samples from inoculated kernels. In addition, the density of particles within a size category varied; lower densities were observed in samples obtained from A. flavus-inoculated kernels.
High Pressure Liquid Chromatographic Determination of Chloramine-T in Food
Authors: Beljaars Paul R , Rondags Theo M M
Published: February 2020

A high pressure liquid chromatographic (HPLC) method for determining chloramine-T (N-chloro-N-sodium-p-toluenesulfonamide) in foods such as ice cream, minced meat, and shrimp is described. Deproteinized samples are treated with sulfite to convert chloramine-T to p-toluenesulfonamide (p-TSA) and extracted, and HPLC analysis is performed on concentrated extracts. Sample extracts are chromatographed on a reverse phase 10 μm Lichrosorb RP-18 column with acetonitrile-water (10+90), and quantitated by an ultraviolet detector (220 nm) and digital integrator. The relationship between recorded peak area and concentration was linear to 0.600 μg p-TSA/μL. The detection limit was 2.5 ng p-TSA/μL, corresponding to a chloramine-T concentration of 0.8 mg/kg in samples. Recoveries of added chloramine-T were 88% for ice cream, 73% for minced meat, and 51% for shrimp. Precision data indicate a relative standard deviation of 1.54 and 2.14% for the complete analysis of ice cream with levels of 15 and 63 mg chloramine-T/ kg (n = 5 determinations), respectively. The HPLC method was applied to chloramine-T determinations in 62 ice cream, 25 minced meat, and 25 shrimp samples.
Further Study of the Spectrophotometric Determination of Capsaicin
Authors: Palacio José Jorge Ramos
Published: February 2020

This study has been undertaken to clarify the previous work on the determination of capsaicin so that the results will be more uniform. For a good colorimetric reaction, the ethyl acetate should have a low water content; 0.1% is optimum concentration for vanadium oxytrichloride. In samples with low Scoville rating, paprika pigment can interfere with the analysis. The absorbance due to this pigment has been studied to determine the absorbance due to capsaicin.
Modified Method for Carbadox in Feeds: Collaborative Study
Authors: Goras John T
Published: February 2020

The official first action method for carbadox in swine feed, 42.C01-42.C04, was modified in 2 respects. First, the samples were leached overnight at room temperature instead of boiled for 1 hr. This change avoided problems with overheating and excessive evaporation. Second, the dilution scheme for samples spiked with carbadox standard solution was changed to give absorbance values that were within the optimum working range of all types of spectrophotometers. The modified procedure was collaboratively studied by 21 laboratories. The repeatability standard deviation (σo) and reproducibility standard deviation (σo) were σ0 = 0.00029% and σx = 0.00056% (8.9% of grand mean) for feeds containing 0.00617% carbadox; and σo = 0.0012% and σx = 0.0019% (9.3% of grand mean) for feeds containing 0.0198% carbadox. The between-laboratory variance ratio was significant for feeds containing 0.0198% carbadox. The mean per cent of intent values for feeds containing 0.00617% carbadox and 0.0198% carbadox were 102% and 104%, respectively. In general, the statistical results were comparable to those previously obtained for the official first action method. Consequently, the modified procedure is not recommended as a replacement for the official first action method.
Infrared Spectrophotometric Method for Analysis of Guthion Insecticide: Collaborative Study
Authors: Cohen Charles J ,   Collaborators:, Audino J B , Byrne M , Grimes G S , Hanks A R , Jennings F A , Looker J , Minyard J P , Winstead G R , Winterle E R
Published: February 2020

A collaborative study on the assay of Guthion (azinphos methyl) has been conducted by 10 laboratories. Data were obtained on a 2 Ib/gal. liquid concentrate and a 50% wettable powder formulation. The procedure specifies extraction and/or dilution followed by infrared absorbance measurement at 654 cm-1. The method has been adopted as official first action.
Mycotoxins in Animal Feedstuffs: Sensitive Thin Layer Chromatographic Detection of Aflatoxin, Ochratoxin A, Sterigmatocystin, Zearalenone, and T-2 Toxin
Authors: Patterson Deryck S P , Roberts Basil A
Published: February 2020

Improvements have been made to a previously described multi-mycotoxin method that involved a membrane cleanup step. Using 2-dimensional thin layer chromatography and appropriate solvent systems, aflatoxin B1 can be detected in mixed feedstuffs and various ingredients at levels ranging from 0.1 to 0.3 μg/kg. Corresponding detection limits for ochratoxin A and sterigmatocystin are 5 to 20 μg/kg and for T-2 toxin and zearalenone 20 to 200 μg/kg.
Comparative Study of Two Methods for Extraction of Aflatoxin from Peanut Meal and Peanut Butter
Authors: Chang Henry H L , Vries Jonathan W De , Hobbs William E
Published: February 2020

The difference between the CB and Best Foods methods in extracting aflatoxins from peanut products has been studied. The CB method yields 60, 121, 35, and 22% higher results for aflatoxins B1, B2, G1, and G2, respectively for 4 samples of peanut meal and 6 samples of peanut butter studied. Both reverse phase liquid chromatography and thin layer chromatography were used to quantitate the extracted aflatoxins.
Detection of Admixtures of Turmeric, Curcuma longa Linn., with Curcuma aromatica Salisb. by Thin Layer and Gas-Liquid Chromatography
Authors: Raghuveer Kalyan G , Govindarajan Venkatesa S
Published: February 2020

Simple and definitive thin layer chromatographic methods are described for the detection of admixtures of Curcuma longa with Curcuma aromatica at the 5% levels. The tests are performed on hexane extracts, thus avoiding distillation of the volatile oil, and are based on the separation of high boiling sesquiterpene compounds by hexane or benzene. Chromatograms are sprayed with vanillin-sulfuric acid or Gibbs reagent to give distinct spots for C. aromatica which are absent from C. longa. Gas chromatography of the extracts also distinguishes the admixtures through a late-eluting peak for C. aromatica.
Elimination of the Hortvet Degree in Cryoscopy
Authors: Richardson Gary H
Published: February 2020

It is recommended that Hortvet degrees be replaced by Celsius degrees in official methods to prevent difficulties in interpretation of data on added water in milk, caused by differences in the 2 thermometers. At one calibration point, this difference amounts to >3% added water in milk, and could affect the action level.
Fungal Growth and the Presence of Sterigmatocystin in Hard Cheese
Authors: Northolt Martin D , Van Egmond Hans P , Soentoro Poppie , Deijll Ellen
Published: February 2020

Molds isolated from visibly molded cheeses in shops, households, and warehouses have been identified. Mold flora of cheeses in shops and households consisted mainly of Penicillium verrucosutn var. cyclopium. On cheeses ripening in warehouses, Penicillium verrucosum var. cyclopium, Aspergillus versicolor, Aspergillus repens, and Penicillium verrucosum var. verrucosum were the dominant mold species. Cheeses ripening in warehouses and molded with A. versicolor were examined for sterigmatocystin. Nine of 39 cheese samples contained sterigmatocystin in the surface layer in concentrations ranging from 5 to 600 µg/kg
High Pressure Liquid Chromatographic Determination of Naphthaleneacetamide Residues in Apples
Authors: Cochrane William P , Lanouette Monique , Grant Ralph
Published: February 2020

A simple, rapid, and accurate method has been developed for the determination of naphthaleneacetamide (NAAmide) residues in apples. After extraction with chloroform, separation is performed on an RP-8 high pressure liquid chromatographic column using acetonitrile-water (30 + 70) buffered to pH 3.5 at a flow rate of 1.7 mi/min. Either a variable wavelength ultraviolet detector set at 220 nm or a fluorometric detector can be used for quantitation. Average recoveries at the 0.01 and 0.1 ppm spiking levels were 83 and 89%, respectively. Incorporation into a previously described method for naphthaleneacetic acid (NAA) residues in apples has resulted in a procedure for the simultaneous determination of NAA and NAAmide.
Extraction and Thin Layer Chromatographic Confirmation of Urine Residues: New Plate Development
Authors: Thrasher Joel J , Hansen Mary Ann ,   Collaborators:, Bradicich R , Kaminski J , Kodoma D , Larose J , Palmer W , Senff W
Published: February 2020

AOAC method 44.146–44.148 (12th ed.) yielded incomplete separation of compounds recovered from urine residues. Problems with decomposition of standard compounds, loss of sample during extraction/concentration, and development of excessive background color during plate spraying were encountered. Modifications were made to deal with these problems as follows: Allantoin standard is now stored in 90% acetone, 30 mL beakers are used instead of conical tubes during extraction, and smaller amounts of pDMAB are used during plate spraying. A collaborative study was conducted to compare sandwich chamber spot separation to larger tank separation. The study showed that total separation of all spots among all analysts was obtained with the sandwich chamber, whereas incomplete separation of spots was obtained with the tank. Also, standard deviation of spot Rr values was smaller with the sandwich chamber. The modified method has been adopted as official first action.
Membrane Filter-Deoxyribonucleic Acid Method of Somatic Cell Counting: Collaborative Study
Authors: Bremel Robert D ,   Collaborators:, Bredar T , Case R , Cathardi B , Ellis R , Kroenke D , Marable V , Meyer D , Meyer R , Miller J , Rothering T , Schwinghammer G , Smith R , Tjornehoj J
Published: February 2020

In the membrane filter-deoxyribonucleic acid test, somatic cells are trapped on a special filter. A chemical determination of the DNA of the trapped material gives an estimate of the number of cells. The MF-DNA was evaluated and compared with the direct microscopic somatic cell counts (DMSCCs) in 10 laboratories. Cell levels in the 10 bulk milk samples analyzed ranged from 380,000 to 1,700,000/mL. Regression analysis gave a relation of 0.181 absorbance at 490 nm, when 2.5 mL of milk was analyzed and 5.0 mL reagent was used for color development. The 95% confidence limits on the slope were 0.158-0.204. Analysis of variance showed that both procedures had significant (P<0.001) systematic errors, but that only the DMSCC method showed a significant laboratory X sample interaction (P<0.001). The repeatability standard deviation of the MF-DNA procedure was 117,000 cells/mL (14%), and the reproducibility standard deviation was 198,000/ mL (23%). This compared favorably with the DMSCC method which had a repeatability of I62,000/mL (19%) and a reproducibility of 287,000/mL (34%). The error of the MF-DNA was constant at all cell counts, whereas there was a tendency for the error to increase in the DMSCC method at high cell counts. This method has been adopted as official first action.
Evaluation of Methanol Extraction for Determination of Badtradn in Feeds
Authors: Ragheb Hussein S ,   Collaborators:, Black L , Brenneke D L , Harpester C , Holm N , Knotts L , Skiles C
Published: February 2020

Five laboratories evaluated methanol extraction for the determination of zinc and methylene disalicylate (MD) bacitracn in swine and poultry feeds at 100 g/ton and 2 premixes labeled 50 g/lb (MD bacitracin) and 40 g/lb (zinc bacitracin). Bacitracin activity was determined on each of 2 days with 2 dilutions on each day. No significant difference was found between dilutions within a day or between days for each sample. The kind of bacitracin or type of feed did not significantly affect results.