bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid Chromatographic Method for Identity, Assay, and Content Uniformity of Five Tricyclic Drugs
Authors: Lovering Edward G , Beaulieu Normand , Lawrence Robert C , Sears Roger W
Published: February 2020

A liquid chromatographic (LC) procedure has been developed for the assay, content uniformity, and identification of single active ingredient solid and liquid formulations of amitriptyline, chlorpromazine, imipramine, thioridazine, and trifluoperazine. The drugs are extracted from their formulations with methanol or dilute hydrochloric acid, and identified by comparison of retention times with those of known standards; drugs are quantitated against these standards with rf/-norephedrine hydrochloride as the internal standard. The precision of replicate injections is better than 2.5% for peak area and better than 1% for peak height. The precision of triplicate determinations of tablet composites is better than 2.2%.
Enzyme Immunoassay for Screening Sulfamethazine Residues in Swine Blood
Authors: Fleeker James R , Lovett Leslie J
Published: February 2020

An enzyme immunoassay (EIA) was developed to screen for residues of sulfamethazine (SMT) and its metabolites in swine blood. Swine blood vas treated with perchloric acid and centrifuged. The supernatant solution was neutralized with K2HP04, centrifuged, and applied to a reverse phase Cg cartridge. The analytes were eluted with methanol- water (2 + 3), and the eluate was diluted and assayed. Average recoveries, using 14C-labeled compounds, were 73, 72, 61, and 62% for SMT, W4-glucosyISMT, iV4-acetylSMT, and W4-desaminoSMT, respectively. Tubes coated with antibody were incubated with the eluate and an SMT-P-galactosidase conjugate. Bound enzyme was detected with fluorogenic substrate. When blood was fortified with 0.1 ppm SMT or a molar equivalent of metabolite, the average relative response of the EIA was 100%, control blood; 61%, SMT; 66%, glucosylSMT; 60%, acetylSMT; and 77% desaminoSMT.
Liquid Chromatographic Determination of Narasin in Feed Premixes
Authors: Hussey Raymond L , Macy Thomas D , Moran John , Loh Andrew
Published: February 2020

A liquid chromatographic (LC) method has been developed to determine narasin in feed premixes. Narasin is extracted from the premix with a methanol-water solvent, and the extracted solution is assayed by using LC. Recovery of narasin from a 12.5 g/lb premix is quantitative (100%), with a relative standard deviation of 1.44%. The results correlated well (coefficient 0.92) with a turbimetric bioassay method.
Simple, Rapid Cleanup Method for Analysis of Aflatoxins and Comparison with Various Methods
Authors: Kamimura Hisashi , Nishijima Motohiro , Yasuda Kazuo , Ushiyama Hirofumi , Tabata Setsuko , Matsumoto Sachiko , Nishima Taichiro
Published: February 2020

A method is described for simple and rapid determination of aflatoxins in corn, buckwheat, peanuts, and cheese. Aflatoxins were extracted with chloroform-water and were purified by a Florisil column chromatographic procedure. Column eluates were concentrated and spotted on a high performance thin layer chromatographic (HPTLC) plate, which was then developed in chloroform-acetone (9 + 1) and/or ethermethanol- water (94 + 4.5 + 1.5)orchloroform-isopropanol-acetone (85 + 5 + 10). Each aflatoxin was quantitated by densitometry. The minimum detectable aflatoxin concentrations (μg/kg) in various test materials were 0.2, B1; 0.1, B2; 0.2, G1; 0.1, G2; and 0.1,M1.Recoveries of the aflatoxins added to corn, peanut, and cheese samples at 10-30 μg/kg were > 69% (aflatoxin G2) and averaged 91%, B1; 89%, B2; 91%, G1; 78%, G2; and 92%, M1. The simple method described was compared with the AOAC CB method, AOAC BF method, and AOAC milk and cheese method. These methods were applied to corn, peanut, and cheese composites spiked with known amounts of aflatoxins, and to naturally contaminated buckwheat and cheese. Recoveries were much lower for the BF method compared with our simple method and the CB method.
Comparison of the Volhard and Potentiometric Methods for the Determination of Chloride in Meat Products: Collaborative Study
Authors: Beljaars Paul R , Horwitz William
Published: February 2020

A collaborative study of the determination of chloride in meat products was conducted by the International Organization for Standardization (ISO) to compare the ISO 1841 method (Volhard titration) with the FAO/WHO Codex Alimentarius Committee method (potentiometric titration). Five canned luncheon meat products containing 0.25-2.0% sodium chloride at 4 different spiking levels were analyzed by 11 laboratories. The data were analyzed by ISO statistics (ISO 5725) and by AOAC statistics (Youden-Steiner), the major differences being in the rejection of outliers and in the statement of precision parameters. Good agreement was found between the mean chloride contents of the products as determined by both methods and with the added amounts, although statistically significantly higher sodium chloride recoveries were obtained with the potentiometric method. The within-laboratory variability (repeatability) is greater for the Volhard method, especially for chloride levels below 1.0%. Therefore it is proposed to set the lowest level of determination for the Volhard method at about 1.0% sodium chloride. The among-laboratories variability (reproducibility) of the potentiometric method was comparable with the results from the collaborative studies for chloride in cheese, giving acceptable values for relative standard deviations of 1.5-3.0% for meat products with 0.3-2.0% added sodium chloride. It is recommended that further work be conducted to reduce or eliminate the systematic error present with the potentiometric method as applied to meat and meat
Electrothermal Atomic Absorption Spectroscopic Determination of Chromium in Plant Tissues:
Interlaboratory Study
Authors: Cary Earle E
Published: February 2020

An electrothermal atomic absorption (ETAA) method for determining chromium in plant tissues was collaboratively studied by 6 laboratories. The sample is digested in nitric, perchloric, and sulfuric acids. Chromium is reduced by sodium sulfite and then separated from the digest matrix by coprecipitation with ferric hydroxide. Iron is removed by dissolution and extraction. The remaining silica is dissolved with hydrofluoric acid, and chromium is then determined. After unusually high and low data sets and remaining outliers were rejected, the CV for samples containing 3 μg chromium was 2% but increased to 84% as the chromium concentration in tissue decreased to 0.02 μg/g. The method is recommended for further study.
Dc Polarographic Assay Of Piperazines
Authors: Walash Mohamed I , Rizk Mohamed S , Ibrahim Fawzia A
Published: February 2020

Piperazine, piperazine salts, and piperazine-containing compounds, e.g., diethylcarbamazine and piperazine theophylline, are determined by direct current polarography of the corresponding nitroso-derivative. The nitroso-derivative exhibits a well defined cathodic wave at — 0.8 V vs SCE. The plot of peak height vs concentration is rectilinear between 1.6 x 10"s and 19.2 x 10-5M. Recoveries from bulk drugs were 97.7-101.12% with a standard deviation of 2.14-3.44. The procedure was successfully applied to analysis of drug content in representative dosage forms with good accuracy.
Thin Layer Chromatographic Identification and Quantitation of Niacin and Niacinamide in Pharmaceutical Preparations
Authors: Sarangi Bandita , Chatterjee Sanat K , Dutta Kajal , Das Saroj K
Published: February 2020

A safe and simple thin layer chromatographic method has been developed for the estimation of niacin and niacinamide in pharmaceutical preparations containing other vitamins, enzymes, herbs, antiamoebic drugs, etc. The method involves removal of excipients from the preparation by ethanol precipitation and isolation of niacin or niacinamide from other ingredients by TLC on silica gel with water as developing solvent, followed by extraction in 0.1N HC1, and spectrophotometric estimation of the vitamin at 262 nm. The percent recoveries for niacin and niacinamide were 100.1 ± 1.9 and 100.2 ± 1.5, respectively.
Gas Chromatographic Detection of D-( - )-2,3-Butanediol and Butyric Acid Produced by
Sporeformers in Cream-Style Corn and Canned Beef Noodle Soup: Collaborative Study
Authors: Schafer Mary L , Peeler James T , Bradshaw Joe G , Hamilton Cleo H , Carver Ruth B
Published: February 2020

A gas chromatographic method that identifies sporeformers as the cause of spoilage in swollen cans of low-acid foods was collaboratively studied in 2 stages. Two organic compounds produced by sporeformers, D-( — )-2,3-butanediol and butyric acid, are measured in the upper phase after centrifugation of the liquid portion of the can contents. Each sample is assayed on 2 packed columns designed for the assay of aqueous solutions of volatile fatty acids, using flame ionization detectors. For study 1,16 duplicate inoculated cans of cream-style corn and beef noodle soup were sent to 9 collaborators. For study 2, 7 collaborators received 11 duplicate inoculated cans of the 2 foods. Duplicate uninoculated cans of each food served as negative controls. The inocula were 6 sporeforming organisms (4 Clostridium and 2 gas-forming Bacillus species) and 2 nonsporeformers. After the deletion of marginal samples, the percentages of correctly identified sporeformers and nonsporeformers in beef noodle soup were 83 (110/132) and 90 (54/60), respectively; corresponding percentages for cream-style corn were 80 (98/123) and 100 (35/35). The method has been adopted official first action.
Quantitative Liquid Chromatographic Method Using Fluorescence Detection for Determining Zearalenone and Its Metabolites in Blood Plasma and Urine
Authors: Olsen Monica E , Pettersson Hans I , Sandholm Kerstin A , Kiessling Karl-Heinz C
Published: February 2020

The liquid chromatographic (LC) method described, suitable for use with both blood plasma and urine, is applicable for determination of zearalenone and α-zearalenol at levels as low as 0.5 ng/mL plasma and 5 ng/mL urine. The sample is incubated overnight β with glucuronidase to analyze for both conjugated and unconjugated forms of zearalenone. The next day, the sample is acidified with H3P04, extracted with chloroform, and evaporated to dryness. The residue is dissolved in toluene and loaded onto a silica gel cartridge which is washed with toluene and eluted with toluene-acetone (88 + 12). The eluate is evaporated, and the residue is dissolved in chloroform, extracted with 0.18M NaOH, neutralized with H3PO4, and re-extracted with chloroform. The chloroform extract is evaporated, dissolved in mobile phase for LC, and injected onto a normal phase column under the following chromatographic conditions: mobile phase of water-saturated dichloromethane containing 2% 1-propanol, and fluorescence detector, excitation wavelength 236 nm, and 418 nm cut-off emission filter. Recoveries of zearalenone and its metabolites from blood plasma and urine are 80-89% in the range 2.0-10 ng standard/mL plasma, and 81-90% in the range 10-30 ng standard/mL urine. This method was used to analyze blood and urine samples from a pig fed zearalenone-contaminated feed (5 mg/kg), corresponding to 80 μg/kg body weight. Zearalenone was rapidly metabolized to a-zearalenol, which appeared in the blood only 30 min after feeding. Almost all zearalenone and αzearalenol was found conjugated with glucuronic acid in both blood plasma and urine.
Liquid Chromatographic Determination of Carbadox and Desoxycarbadox in Medicated Feeds and in Porcine Gastrointestinal Tract
Authors: Graaf Gerrit J De , Spierenburg Theodorus J
Published: February 2020

A liquid chromatographic method for the assay of carbadox and desoxycarbadox in medicated feeds and porcine stomach and intestinal contents is described. Samples were extracted with dimethylformamidewater and cleaned up on an alumina column. The eluate was chromatographed using either gradient elution for simultaneous assay of both compounds or isocratic elution for carbadox only. Detection of carbadox by its native fluorescence yielded a sensitive and specific assay without interferences by metabolites or matrix components. The optimal UV absorption of desoxycarbadox was at 280 nm. Mean recoveries of carbadox in spiked feed and stomach contents were 104 and 97%, respectively; mean recovery of desoxycarbadox in stomach contents was 106%. The day-to-day reproducibility for carbadox in different feed samples and stomach contents samples had a coefficient of variation of 6-13%.
Sensitive Enzyme Immunoassay of Colistin and Its Application to Detect Residual Colistin in Rainbow Itout Tissue
Authors: Kitagawa Tsunehiro , Ohtani Wataru , Maeno Yoshiko , Fujiwara Kunio , kimura Yukio
Published: February 2020

An antibody against colistin (CL), an antibiotic effective for gramnegative bacteria, was produced in rabbits immunized with a colistinprotein conjugate. The conjugate was prepared by a novel and convenient procedure devised to couple an amino group of CL to thiol groups of bovine serum albumin (BSA) introduced by thiol exchange reduction of its disulfide bonds with dithiothreitol, using N-(m-maIeimidobenzoyloxy) succinimide (MBS) as a cross-linker. Enzyme labeling of CL with β-D-galactosidase was performed by utilizing another crosslinker, N(γ-maleimidobutyryIoxy)succinimide, by means of a convenient labeling method. A double antibody enzyme immunoassay of CL, which could determine as little as 30 ng/mL of CL, was developed using labeled CL and anti-CL antiserum. With this assay, drug levels were easily determined in fish tissue after CL administration. The enzyme immunoassay should provide a useful tool for detection and quantitation of residual drugs in foods and related products.
Improved Liquid Chromatographic Determination of Riboflavin in Milk and Dairy Products
Authors: Ashoor Samy H , Knox Michael J , Olsen, Jacquelyn R , Deger Dru Ann
Published: February 2020

Reported here is a simple liquid chromatographic (LC) method for the i determination of riboflavin in milk (liquid, evaporated, and dry), yogurt, ' and cheese. The method involves passing liquid samples or filtrates of semisolid and solid samples through a Clg cartridge. Retained riboflavin is then eluted with an aliquot of 50% methanol in 0.02M acetate buffer of pH 4. A volume of the eluate is injected into the LC system | consisting of a CJ8 column, a solvent of water-methanol-acetic acid (65 + 35 + 0.1, v/v) with a flow rate of 1 mL/min, and a UV detector set at 270 nm. The method is precise and accurate and compares i favorably with the present AOAC method. Moreover, it involves fewer sample preparation steps and has a total analysis time of less than 1 h.
Simplified Cleanup and Liquid Chromatographic Determination of Oxamyl Residues in Potato Tubers
Authors: Mcgarvey Brian D , Chiba Mikio , Olthof Theo H A
Published: February 2020

A simple and efficient method is presented for the extraction, cleanup, and liquid chromatographic (LC) determination of oxamyl residues in potato tubers. Samples are extracted with methanol, partitioned into dichloromethane, and cleaned up using Sep-Pak Florisil cartridges. LC determination is performed using a Zorbax PSM 60 size exclusion ; column with an acetonitrile-water (1 + 9) mobile phase and UV detection at 254 nm. Recovery of oxamyl from spiked control tubers averaged 94.1 and 85.9% at fortification levels of 0.4 and 0.08 \μg oxamyl/g tuber, respectively. The minimum detectable concentration of oxamyl by this method is 0.01 μg/g
Statistical Examination of AOAC Use-Dilution Method for Testing Disinfectant Efficacy
Authors: Trout Richard I
Published: February 2020

The AOAC use-dilution method is examined from a statistical viewpoint by using the fundamental concept of operating characteristic curves to focus attention on the inadequately defined aspects of the acceptance/ rejection criteria used for disinfectant registration and enforcement purposes.
Determination of Total and Free Water in Triple Superphosphate Fertilizers by Using Thermal Analysis
Authors: Kostyrko Krystyna , Skoczylas Malgorzata , Klee Andrzej
Published: February 2020

Thermal analysis methods were used to study dehydration of triple superphosphate. A redrying procedure followed by Q-derivatographic analysis (under quasiisobaric and quasiisothermal conditions) as well as differential scanning calorimetry (DSC) was applied. Attempts were made to establish the correct drying-oven temperature for determination of water content, i.e., the temperature at which free or total water is removed from the fertilizer. Thermal decomposition of monocalcium orthophosphate monohydrate, the major component of triple superphosphate, was studied and a model was advanced for the reactions that occur during decomposition of this salt. The free water was completely released when superphosphate was heated at a constant temperature of 85°C. The total water was entirely released at 160°C. At 150°C, the process of removing the water of crystallization from the orthophosphate was disturbed by other concomitant dehydration processes which result in irreversible decomposition of this salt. The results obtained indicate that the thermal methods of analysis used are complementary.
Oxidation and Hydrolysis Determination of Sulfur Amino Acids in Food and Feed Ingredients: Collaborative Study
Authors: Macdonald John L , Krueger Mark W , Keller John H
Published: February 2020

Samples of 6 food and feed ingredients and a purified protein, plactoglobulin, were analyzed by 7 laboratories to determine the concentrations of cysteine as cysteic acid and methionine as methionine sulfone. Samples were oxidized by reaction with performic acid before hydrolysis with 6N HC1. The free amino acids were then separated and measured by ion-exchange chromatography on dedicated amino acid analyzers. Each laboratory was provided with a detailed method as well as sealed vials containing solutions of standards. For the determination of cysteine as cysteic acid, the coefficients of variation between laboratories for duplicate samples ranged from 7.13 to 10.8% for the 6 ingredients. For the determination of methionine as methionine sulfone, the coefficients of variation between laboratories for duplicate samples ranged from 1.18 to 12.8% for the 6 ingredients. Cysteine and methionine recoveries were determined by analysis of β-Iactoglobulin and were based on expected levels of each amino acid from amino acid sequence data. The mean recovery of cysteine was 95% with a range of 91-101%. The mean recovery of methionine was 101% with a range of 98-106%. This method has been adopted official first action.
Extraction of Light Filth from Unground Marjoram: Collaborative Study
Authors: Dent Russell G , Glaze Larry
Published: February 2020

Ihe present method for filth in unground marjoram is conducted in 2 parts. The first of these, which is for heavy filth and sand, requires the spice to be boiled with petroleum ether, then floated off with chloroform and, if needed, carbon tetrachloride. The second part, which is for light filth, is dependent on completion of the heavy filth section. After the spice is air-dried, the light filth is extracted with heptane and water. The proposed method was developed to make light filth independent of heavy filth analysis, improve filth recoveries, and reduce microscopic examination time. The light filth is extracted by ethanol defatting followed by a combination 15-60% ethanol/mineral oil extraction in a Wildman trap flask. Tween 80-NaEDTA solution is added to the trapping system to reduce the rising of excess plant material to the trap interface. The official method (AOAC 13th edition sees 44.142,44.120(b)) produced an average of 8 extraction papers per test portion and microscopic examination took an average of 88 min per test portion. The official method gave average recoveries of 14% for rodent hairs and 26% for insect fragments with 2 spike levels of 15 and 30 for each filth element. Recoveries of the 2 levels of each spike were not significantly different (P > 0.05). The proposed method gave average recoveries of 73% for rodent hairs and 70% for insect fragments. The proposed method has been adopted official first action to replace AOAC 13th edition sees 44.142 and 44.120(b) for unground marjoram only
Quality Assurance in the Pesticide Product Laboratory
Authors: Hill Dean F
Published: February 2020

Although the overall quality assurance concepts and goals for pesticide formulation analysis are similar to those required of an environmental or trace level analysis laboratory, some important distinctions exist, particularly for quality control. Generally, target levels (label values) are known and pesticide identification can be assumed, thus minimizing the need for verification of pesticide identity and for detailed confirmation of quantitative results reasonably close to the label value. Exceptions are cross-contaminant screening and by-product analysis. Quality control efforts in the formulation laboratory are concentrated on those samples falling outside the established acceptance criteria. The use of official (AOAC/Collaborative International Pesticides Analytical Council (CIPAC)) methodology, replicate determinations, second analyst confirmation, and alternative methodology (if necessary) is stressed. Specific attention must also be paid to the quality and preparation of analytical reference standards.
Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Meats: Validation Study for Swine and Beef Fats
Authors: Ault James A , Spurgeon Timothy E , Gillard Douglas S , Mallinson Edward T
Published: February 2020

A validation of a previously studied method for determining organochlorine residues in poultry fat was conducted to extend the usefulness of the method to beef and swine fats. The validation samples consisted of 16 materials all analyzed in duplicate. Fortification levels ranged from 0.02 to 1.2 ppm for a-BHC, lindane, cis- and Irans-chlordane, octachlor epoxide, o,p'- and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 101 % with a range of 7 9 - 113%, not including toxaphene. The ranges of coefficients of variation wtreCV. = 0-23.37% and CVX = 3.74-26.19%. The results were comparable to the previous collaborative study of the same method for poultry fat. The extended method has been adopted official first action
Multiresidue Method for Determination of Eight Neutral β-Lactam Penicillins in Milk by Fluorescence-Liquid Chromatography
Authors: Munns Robert K , Shimoda Wilbert , Roybal Jose E , Vieira Cassandra
Published: February 2020

A method of determining total penicillins begins with an enzymatic hydrolysis of the (J-Iactam ring to form their respective penicilloate product. Acetonitrile precipitates much of the casein and protein, which are then separated from the liquid by centrifugation. The lipids are removed from the aqueous fraction with methylene chloride. Mercuric chloride is added, which reacts with the penicilloate to liberate the side chain that has a terminal aldehyde. These penilloaldehyde products are extracted with methylene chloride and are subsequently reacted with dansyl hydrazine. The resulting fluorolabeled side chains are separated by liquid chromatography on a C18 column with acetonitrile- water as mobile phase. The fluorescence is measured by the mercury line at 254 nm excitation wavelength and a 500 nm filter on the emission side. The overall average recoveries from milk spiked at 25, 50, and 100 ppb are benzyl penicillin 79.4%; phenoxymethyl penicillin 59.7%; phenethicillin 75.9%; nafcillin 87.7%; methacillin 47.5%; oxacillin 57.6%; cloxicillin 37.3%; and dicloxicillin 26.4%.
Detection of Tricresyl Phosphates and Determination of Tri-o-Cresyl Phosphate in Edible Oils
Authors: Krishnamurthy Mahishi N , Rajalakshmi S , Kapur Om Prakash
Published: February 2020

Tricresyl phosphate (TCP) in contaminated edible oils was extracted using acetonitrile and detected by thin layer chromatography as well as gas chromatography (GC). The chromatoplate was developed with isooctane-ethyl acetate (90 + 10) and visualized by spraying with 2,6- dichloroquinone chloroimide. TCP gives a characteristic blue-violet spot when heated at 100°C for 15 min. The method is direct and sensitive and can be used to detect as low as 2.5 p.g TCP or TOCP (tri-o-cresyl phosphate). GC was carried out using 10% OV-101 as the stationary phase and flame ionization detection for confirmation and quantitation of TOCP in oils.
Microwave Oven Drying Determination of Total Solids in Processed Tomato Products: Collaborative Study
Authors: Chin Henry B , Kimball John R , Hung Joyce , Allen Bradford
Published: February 2020

Fourteen laboratories analyzed 7 samples of tomato products with total solids content ranging from 6.5 to 40.2%. Samples were analyzed directly with the exception of samples with solids contents greater than 15%, which were diluted with water (1 + 1 for up to 30% solids and 1 + 3 for greater than 30% solids). The 2-4 g samples were dried at 100% power for 4 min. The results of the collaborative study showed good repeatability and reproducibility: 5„ = 0.16 (CV = 0.46%) and S, = 0.36 (CV = 1.06%) for the higher solids samples and S„ = 0.37 (CV = 3.76%) and Sx = 0.14 (CV = 1.41%) for samples with total solids up to 15%. Results were compared with those obtained using vacuum oven drying. No difference was seen in the results by the 2 methods at the 95% level of confidence. The microwave oven drying method has been adopted official first action as an alternative to the vacuum oven drying method for total solids.
Multiresidue Method for Quantitative Determination of Organophosphorus Pesticides in Foods
Authors: Blaha John J , Jackson Patricia J
Published: February 2020

A multiresidue method for the quantitative determination of organophosphorus pesticides in foods from the Food and Drug Administration's Total Diet Study is described. The organophosphorus pesticides are separated on the basis of polarity and determined in both fatty and nonfatty foods with a minimum of interferences. The foods analyzed included raw and cooked individual foods as well as combination dishes, water, and whiskey. Recoveries of 17 organophosphorus pesticides in 41 foods ranged from about 80 to 118%.
Hydrolysate Preparation for Analysis of Amino Acids in Sorghum Grains: Effect of Oxidative Pretreatment
Authors: Elkin Robert G , Griffith Joseph E
Published: February 2020

Sorghum samples were either untreated or oxidized with performic acid (PA) before hydrolysis, and their amino acid contents were determined by cation exchange chromatography using an amino acid analyzer. HC1 was used to destroy excess PA. Oxidative pretreatment of the samples resulted in increased yields of Cys (as cysteic acid), Met (as Met dioxide), and His, destroyed Tyr and Phe, and resulted in the appearance of an extraneous peak which most likely consisted of halogenation by-products (HBP) of Tyr and Phe. The destruction of Tyr and Phe occurred despite the presence of phenol, a halogen scavenger, in both the PA and hydrolysis reagents. The higher His values observed in all oxidized samples most likely resulted from the co-elution of His with Tyr and Phe HBP. It was concluded that the complete (except Trp) amino acid content of a feedstuff cannot be accurately determined from only one oxidized hydrolysate preparation by using this particular procedure.
Screening and Quantitation of Ochratoxin A in Corn, Peanuts, Beans, Rice, and Cassava
Authors: Soares Lucia M Valente , Rodriguez-Amaya Delia R
Published: February 2020

To answer the need for simple, economical, rapid methods for mycotoxins, a procedure for screening and quantitation of ochratoxin A was developed. A methanol-aqueous KC1 extraction is used, followed by cleanup with clarifying agents and partition into chloroform. Part of the chloroform extract is used for screening and the other part for quantitation by thin layer chromatography (TLC). The screening procedure takes 40 min, using a silica gel/aluminum oxide minicolumn developed for this purpose. The limits of detection are 80 and 10 |xg/ kg, respectively, for minicolumn screening and TLC quantitation. Ammonium sulfate is efficient in cleaning samples of corn and cassava; cupric sulfate is better with peanuts, beans, and rice. Tests were conducted on triplicate spiked samples of yellow corn meal, raw peanuts, dried black beans, polished rice, and cassava flour at different levels (400, 200, 80, 40, and 10 p-g/kg). Recoveries ranged from 86 to 160% and the coefficients of variation ranged from 0 to 26%.
Determination of Monensin Sodium Residues in Beef Liver Tissue by Liquid Chromatography of a Fluorescent Derivative
Authors: Martinez Elizabeth E , Shimoda Wilbert
Published: February 2020

Monensin sodium does not have an ultraviolet (UV) absorbance above 220 nm, and therefore cannot be detected by liquid chromatography (LC) with a UV detector. A method was developed in which monensin residues are extracted from beef liver tissue, acetylated, partitioned, and reacted with 9-anthryldiazomethane to form a fluorescent derivative for quantitation by LC. The reliable level of sensitivity is 50 ppb, but 15 pjib can be detected. Recoveries ranged between 71 and 96% with an average of 83.5%.
Permethrin and Its Two Metabolite Residues in Seven Agricultural Crops
Authors: George Donald A
Published: February 2020

Metabolite residues of permethrin are not reported in the literature for most agricultural crops. This paper reports residues of permethrin and its 2 metabolites (dichlorovinyl acid and metaphenoxybenzyl alcohol) in 7 different agricultural crops (Chinese cabbage, spinach, asparagus, raspberries, green peas, turnip roots, and turnip greens). Permethrin residues declined approximately 85% within 7 days after treatment in all crops. In most cases, the acid metabolite residues peaked at 3 days, and declined after that. Translocation of residues into turnip roots was very slight; the average was less than 0.05 ppm for permethrin and alcohol metabolite residues and none was detected for the acid metabolite residue. Permethrin residues in the turnip greens averaged approximately 2 ppm for the 0.112 kg ai/ha treatment, and 6 ppm for the 0.224 kg ai/ha treatment.
Determination of Gibberellic Acid Residues on Fruits by Synchronous Scanning Derivative Spectrofluorometry
Authors: Blanco C Cruces , Sánchez F García
Published: February 2020

A synchronous derivative spectrofluorometric method is described for the determination of the plant growth regulator, gibberellic acid (GA3). The method is based on the formation of a fluorogen in concentrated sulfuric acid. The reaction is carried out at 85% sulfuric acid and in aqueous medium. The common fluorometric method with a linear dynamic range of 137-400 ppb, and a detection limit of 48 ppb is described. The synchronous first and second derivative method has linear dynamic ranges between 7.6-40 ppb and 12-40 ppb, with detection limits of 3.5 and 6.7 ppb, respectively. The influence of reaction variables and of other plant growth regulators present, and the application to residues on oranges, lemons, and grapes, are also described.
Evaluation of Monier-Williams and Committee Methods for Bisulfite Determination as Used by the Potato Processing Industry
Authors: Moylan John G , Bowes F William , Pappin Walter J
Published: February 2020

The Monier-Williams and the iodometric Committee methods were evaluated for the determination of bisulfite in potato products. Both methods showed critical problems in accuracy and precision at concentrations below 60 ppm. Sensitivity levels of 25 ppm are possible with the Monier-Williams method. However, accuracy problems reflected by the coefficients of variation (Monier-Williams, 47.4%; Committee, 78.2%) as well as variability in recoveries and blank values for both methods produce qualitative rather than quantitative analytical data at low SO2 concentrations
Determination of Biuret in Urea and Mixed Fertilizers by Cupric Ion Selective Electrode
Authors: Corominas Luis F , Navarro Roberto A , Rojas Pedro , Cruz José L
Published: February 2020

A method for determining biuret in urea and mixed fertilizers by using a cupric ion selective electrode (CISE) has been developed to take advantage of the simplicity of the apparatus. The method is based on the same principle as the atomic absorption spectrophotometric (AAS) method, 2.091-2.093: formation of a biuret-copper complex, elimination of excess copper, and determination of complexed copper. However, some changes were needed to eliminate starch and alcohol interferences. The method was tested for ruggedness and then compared with the AAS method for 4 fertilizer samples. Averages and variances were equivalent at the 99% confidence level according to t- and F-tests. A collaborative study is recommended to compare behavior of both methods in different laboratories.
Determination of Sulfur Dioxide in Grapes and Wmes
Authors: Ough Cornelius S
Published: February 2020

Reasons for using SO2 in wine and the theoretical aspects of this use are discussed. Data are summarized on the amounts of SO2 found in wines in California and around the world. Methods of analysis are discussed.
Determination of Iodine Values of Lipids by Bromide Ion Selective Electrode
Authors: Abdel-Moety Ezzat M , Ahmad Abdel-Kader S , El-Din Mohie Sharaf
Published: February 2020

A semimicro method for determination of iodine values of lipids is described. An accurately weighed smear of sample (10-20 mg) on a strip of ashless filter paper, 14 × 40 mm, is brominated with bromine vapors for about 5 min. Excess bromine adsorbed on the filter paper is allowed to sublime. Bromine absorbed by the sample is directly related to the degree of unsaturation. Paper with brominated sample is subjected to oxygen flask combustion in the presence of 2 mL 1M sodium hydroxide solution and 10 mL water as absorbing liquid. Bromide formed, which is equivalent to unsaturation, is determined by bromide ion selective electrode. Bromide ions can be also determined by gravimetry or by indirect argentometric titration. The results were statistically analyzed. The iodine values of some fatty acids and oils, determined by this technique, are in accord with those of some officially approved methods.
Liquid Chromatographic Determination of Zoalene and Its Metabolites in Chicken Tissues with Electrochemical Detection
Authors: Parks Owen W , Doerr Robert C
Published: February 2020

A procedure is described for the quantitation of Zoalene (3,5-dinitro-o-toluamide) and its 2 major monoamino metabolites in chicken tissues. The method includes blender extraction of tissue with chloroformethyl acetate (1 + 1), adsorption of the drug and metabolites on neutral alumina, and subsequent elution of the residues with pH 3.5 formate buffer-methanol (6.5 + 3.5). Recovered residues were separated on a 5 μ C18 column with the alumina eluting solvent as the LC mobile phase. The parent drug and metabolites were detected and quantitated with an electrochemical detector in the reductive mode with a minimum level of reliable measurement of 0.1 ppm. Overall mean recoveries greater than 85% were obtained with Zoalene and its 2 monoamino metabolites in breast, thigh, and liver tissues fortified with 0.25-2.00 ppm. The results on tissues from chickens fed a diet containing 0.0125% Zoalene are presented.
Practical Screening Procedure for Sulfathiazole in Honey
Authors: Schwartz Daniel P , Sherma Joseph
Published: February 2020

A simple, inexpensive procedure is described for rapidly screening small samples of honey for sulfathiazole (ST), a drug formerly used but not approved in the United States for the prophylactic treatment of American foulbrood disease of bees. The method uses 2 plastic tubes arranged in tandem. The upper tube contains a bed of alumina, which removes some interfering pigments. The lower tube contains a very small bed of anion exchange resin in the HSO4- form, which traps the ST. The drug is eventually eluted and detected using the Bratton-Marshall diazotization-coupling reagents. Honey containing 0.1 ppm ST can be readily detected. An optional dye concentration step permits the detection of as little as 25 ppb ST.
Polarographic Determination of Antihistamines by Complexation with Cd(II)
Authors: Temizer Aytekin , Özaltin Nuran
Published: February 2020

The polarographic behavior of the complexes formed by Cd(II) ion with ethanolamine derivative antihistamines such as diphenhydramine hydrochloride, dimenhydrinate, and chlorphenoxamine hydrochloride was studied. Antihistamines form spontaneous complexes with Cd(II) ion in the presence of KNO3. In addition, pH 8.00 borate buffer was added to increase the differential pulse polarogram peak height, and tetraalkyl ammonium salts were added to increase the linear range. The method of determination developed has been applied to commercial tablet, capsule, elixir, and injection forms of ethanolamine derivative drugs and has been compared with official methods.
Outliers in Collaborative Studies: Coping with Uncertainty
Authors: Albert Richard H
Published: February 2020

An overview is given of the options available in detecting and dealing with outliers in collaborative studies. The fundamental points of agreement and disagreement are highlighted. The common sense approach of just looking at the data is emphasized. The importance is stressed of making a harmonized choice of outlier treatments, even though such a choice may not be optimal for all circumstances.
Rapid, Semimicro Method for Determination of Polycyclic Aromatic Hydrocarbons in Shellfish by Automated Gel Permeation/Liquid Chromatography
Authors: Musial Charles J , Uthe John F
Published: February 2020

A simple, rapid, easily automated method is described for the determination of polycyclic aromatic hydrocarbons (PAHs) in shellfish such as American lobster (Homarus americanus) and blue mussel (Mytilus edulis). PAHs are extracted from small amounts (1-8 g) of tissue by saponification in IN ethanolic potassium hydroxide followed by partitioning into 2,2,4-trimethylpentane. This solution is evaporated just to dryness by rotary evaporation and the residue is dissolved in cyclohexane- dichloromethane (1 + 1) for gel permeation chromatography (GPC) on Bio-Beads SX-3. The GPC procedure is ideal as a screening method in the range 25-18 000 ng PAHs/g tissue. If individual PAH measurements are required, the appropriate GPC fraction is collected and PAHs are separated by reverse phase liquid chromatography (LC) with fiuorometric detection. Individual PAHs at concentrations as low as 0.25-10 ng/g can be determined. Recoveries of added fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[e]pyrene, benzo[A]fluoranthene, benzo[b]fluoranthene, benzo[α]pyrene, dibenz[a,h]anthracene, benzo[ghi]perylene, and indeno[l,2,3-cd]pyrene were quantitative, with relative standard deviations ranging from 0.0 to 16.9%.
Colorimetric Determination of Alkaline Phosphatase as Indicator of Mammalian Feces in Corn Meal: Collaborative Study
Authors: Gerber Harriet ,   Collaborators:, Beavin B , Brown S , Bryce J , Deblois B , Klein R , Knueppel J , LaRose J , Lmdroth S , Mayers D , McDonnell J , Schneider P , Trauba R
Published: February 2020

In the official method for rodent filth in corn meal, filth and corn meal are separated in organic solvents, and particles are identified by the presence of hair and a mucous coating. The solvents are toxic, poor separation yields low recoveries, and fecal characteristics are rarely present on all fragments, especially on small particles. The official AOAC alkaline phosphatase test for mammalian feces, 44.181-44.184, has therefore been adapted to determine the presence of mammalian feces in corn meal. The enzyme cleaves phosphate radicals from a test indicator/substrate, phenolphthalein diphosphate. As free phenolphthalein accumulates, a pink-to-red color develops in the gelled test agar medium. In a collaborative study conducted to compare the proposed method with the official method for corn meal, 44.049, the proposed method yielded 45.5% higher recoveries than the official method. Repeatability and reproducibility for the official method were roughly .1.8 times more variable than for the proposed method. The method has been adopted official first action.
Production and Isolation of Aflatoxin M1 for Toxicological Studies
Authors: Hsieh Dennis P H , Beltran Linda M , Fukayama Mark Y , Rice David W , Wong Jeffrey J
Published: February 2020

One hundred mg aflatoxin Mi was produced and purified for toxicological studies. Aspergillus flams NRRL 3251 was cultured on rice to produce aflatoxins B1, B2, M1, and M2. B1 and B2 were separated from M1 and M2 by a normal phase low pressure liquid chromatography (LC) column. M1 was then separated from M2 by a reverse phase low pressure LC column. Recoveries of aflatoxins from the LC columns were about 90%. The purified M1 was confirmed by ultraviolet-visible spectrometry, mass spectrometry, nuclear magnetic resonance spectrometry, optical rotation, and its mutagenicity to Salmonella typhimurium TA98.
Liquid Chromatographic Determination of Chlorpropamide in Tablet Dosage Forms: Collaborative Study
Authors: Everett Richard L ,   Collaborators:, Aranda E , Colon M , Illuminati J , Kelley N , Roberts S , Shostak D
Published: February 2020

A reverse-phase liquid chromatographic method was developed for determining chlorpropamide in tablet dosage forms. Linearity was established over the range 0.2-2.0 μg at a wavelength of 240 nm. The Associate Referee obtained a mean recovery for a synthetic tablet mixture of 99.2%, with a relative standard deviation (RSD) of 1.41. For an authentic tablet mixture, collaborators obtained a mean recovery of 99.6% with an RSD of 0.60%. RSDs were 1.24% for 250 mg/tablet commercial product and also for 100 mg/tablet commercial product. The method has been adopted official first action.
Headspace Gas Chromatographic Method for Determination of Ethanol in Canned Salmon: Collaborative Study
Authors: Hollingworth Thomas A , Throm Harold R , Wekell Marleen M , Trager William F , O’Donnell Michael W ,   Collaborators:, Hons F , Lerke P , Mowdy D , Saxton W , Wiggin K , Wood J
Published: February 2020

Six laboratories collaboratively studied a headspace gas chromatographic method for determination of ethanol in the aqueous phase of canned salmon. Ethanol is determined by a headspace sampling technique with tert-butanol as the internal standard, using a gas chromatograph equipped with a Super Q column and a flame ionization detector. With outliers excluded, the mean recoveries from samples spiked with 25.1 and 78.4 ppm ethanol were 112 and 110%, respectively. For the 4 sample pairs quantitated, repeatability coefficients of variation ranged from 1.42 to 4.25% and reproducibility coefficients of variation from 2.55 to 8.09%, with 3 of the 4 reported values less than 5%. The method has been adopted official first action.
Gas Chromatographic Profile Analysis of Basic Nitrogen-Containing Aromatic Compounds (Azaarenes) in High Protein Foods
Authors: Grimmer Gernot , Naujack Klaus-Werner
Published: February 2020

A method is described for the determination of basic nitrogen-containing polycyclic aromatic compounds (N-PACs, azaarenes) in meat. The enrichment procedure includes liquid-liquid partition (dimethylformamide-water-cyclohexane), extraction of N-PACs by sulfuric acid, reextraction after neutralization by cyclohexane or, alternatively, by nonadsorbing ion exchange chromatography. Further purification is performed by column chromatography on Sephadex LH20 using a dosed system to avoid sample contamination by laboratory pollutants. N-PACs are analyzed by capillary gas chromatography and measured by comparing to the corresponding peak areas of an internal standard (e.g., lO-azabenzo(a)pyrene). The limit of detection of this method ranges from 0.1 to 0.4 ng for benzacridines, dibenzacridines, and their methyl derivatives. The results of a collaborative study, stimulated by IUPAC, are reported: Coefficients of variation for the various azaarenes were 4.0-13.6% for the check analysis and 10.4-25.4% for a spiked ham sample. Consequently, IUPAC suggests this procedure as a recommended method.
Variability of Mouse Bioassay for Determination of Paralytic Shellfish Poisoning Toxins
Authors: Park Douglas L , Adams Willard N , Graham Stuart L , Jackson Randolph C
Published: February 2020

Toxic shellfish extracts and paralytic shellfish poison (PSP) standard solutions, tested over a range of pH levels, storage conditions, and temperatures, were monitored for toxin concentration, using the mouse bioassay and thin layer chromatography (TLC). A comparison of PSP toxin concentrations in toxic shellfish extracts and PSP standard solutions when dilution was varied suggests that other factors in the shellfish extracts contribute to the toxicity in mice; the closest agreement was at the death time range of 5-8 min. The toxicities of PSP standard solutions at pH levels ranging from 2 to 6 and held at 4°C for various times were relatively constant; however, there was a gradual decrease in toxicity with pH 6 solutions. Also, standard solutions (pH 6) held at 4°C for 28 days showed a 50% decrease in toxicity when the pH was adjusted to 2. TLC analyses of PSP standard solutions and toxic shellfish extracts revealed multiple spots at the Rf ranges of saxitoxin/neosaxitoxin and gonyaulax toxins I-IV. PSP standard solutions usually had a single spot in the saxitoxin/neosaxitoxin area. No attempt was made to confirm the identity of these compounds. Previously tested toxic shellfish extracts with subsequent pH adjustment to 1.5 and additional heat treatment (100°C for 5 min) showed no appreciable difference in mouse toxicity. The use of antifoaming agents during the acid extraction step did not affect the final amounts of PSP obtained
Gas Chromatographic Determination of the Plant Growth Regulator Flurprimidol in Soil and Soil-Grass Samples
Authors: West Sheldon D , Rutherford Bonnie S
Published: February 2020

A method is described for the determination of flurprimidol residues in soil and soil-grass samples. Flurprimidol is extracted from the sample by refluxing with methanol-water. An aliquot is partitioned into hexane and purified by alumina B Sep-Pak column chromatography. The compound is detected and measured by gas chromatography with electron capture detection. Residue identity is confirmed by gas chromatography-mass spectrometry with detection at m/z 269.0. The detection limit is 0.01 ppm, and recoveries for control samples fortified with flurprimidol at 0.01-2.0 ppm averaged 80% for soil and 78% for soil-grass samples.
Identification of cis- and trans-1,1,2,3,4-PentachIoro-4-[1-methylethoxy]-l,3-butadiene Residues in Mississippi River Fish
Authors: Yurawecz Martin P , Chen Jo-Yun T , Puma Bartholomew J
Published: February 2020

The cis- and trans-isomers of 1,1,2,3,4-pentachloro-4-[1-methylethoxy]-1,3-butadiene have been identified as contaminants in fish caught from the Mississippi River at St. Louis, MO, and as far as 150 miles south of that location. Up to 0.1 ppm of the cis-isomer and 0.8 ppm of the trans-isomer were determined by using a method based on the AOAC multiresidue method for detecting organochlorine and organophosphorus pesticides. In tests of the modified AOAC method on spiked fish, both isomers were quantitatively recovered (95-106%). A mixture of the cis- and trans-isomers was synthesized by reacting hexachlorobutadiene with sodium isopropoxide. Separation of the reaction products by Florisil column chromatography provided reference standards of the individual isomers for identification and quantitation of the residues. The stereospecificity of the synthesis reaction and the infrared and mass spectral data used to verify the structures of the products are discussed.