bluuebunny/crossref_metadata_2025 huggingface dataset:
High Pressure Liquid Chromatographic Determination of the Intermediates/Side Reaction Products in FD&C Red No. 2 and FD&C Yellow No. 5 : Statistical Analysis of Instrument Response
Authors: Bailey Catherine J , Cox Elizabeth A , Springer Janet A
Published: February 2020

The statistical methods of regression analysis are applied to calibration data obtained by high pressure liquid chromatographic analysis for the intermediates and side reaction products of FD&C Yellow No. 5 and the former FD&C Red No. 2. Equations are presented which allow calculation of the regression line equation, correlation coefficient, the upper prediction limit on the blank (YUB)? t n e limit of detection in terms of concentration (XLD), response above which quantitation is performed (YQ) , and prediction intervals for a specific response. The HPLC methods for FD&C Yellow No. 5 and the former FD&C Red No. 2 are evaluated based on those calculations.
Further Studies on the Colorimetric Determination of Ronidazole in Feeds
Authors: Fink David W , Pivnichny James V , Shim Jung-Sook K , Tolan John W
Published: February 2020

A previously published colorimetric method for determining ronidazole, (l-methyl-5-nitroimidazoI- 2-yl) methyl carbamate, can be used as an analytical technique for measuring the stability of this drug in medicated feeds. Although the color reaction per se is not selective, elution profiles of ronidazole and its demonstrated hydrolytic degradation product, l-methyl-2-hydroxymethyl- 5-nitroimidazoIe, show that the chromatographic separation used in the sample preparation efficiently isolates the drug from the degradation product. No interference was found in feeds containing 0.010% ronidazole and up to 0.010% degradation product.
Column Chromatographic Determination of Mirex, Photomirex, and Poly chlorinated Biphenyls in Lake Sediments
Authors: Chau Alfred S Y , Babjak Ludwig J
Published: February 2020

Mirex (dodecachlorooctahydro -1,3,4 - metheno-2H-cyclobuta[cd]pentalene) and photomirex (8-monohydromirex) are separated from interfering polychlorinated biphenyls (PCBs) in lake sediments. Sediment samples were extracted with acetone-hexane (1+1) in an ultrasonic apparatus and the extracts were cleaned up on conventional Florisil columns. A charcoal-polyurethane column was used to quantitatively separate Mirex and photomirex from PCBs. Recoveries of Mirex, photomirex, and PCBs from the spiked sediments were each >95% at 0.1 to 3 ppb levels.
Ultraviolet Spectrophotometric Determination of Benzoic Acid in Soy Sauce
Authors: Goo Reginald K S , Wakatsuki Helen , Kanai Hiromitsu
Published: February 2020

Proteins and other interfering substances are precipitated from soy sauce, using sodium tungstate under acidic conditions. After centrifugation, the supernate is successively extracted with ethyl ether to isolate the benzoic acid in the organic solvent. The ettiyl ether extract is washed with dilute HC1. Benzoic acid is then quantitatively determined by ultraviolet spectrophotometry. Recovery of sodium benzoate added to soy sauce ranged from 94 to 104%.
Sample Homogenization Procedure for Determination of Lead in Canned Foods
Authors: Jones John W , Boyer Kenneth W
Published: February 2020

To improve the homogeneity of canned foods before Pb determination, composited samples or single can contents (150—500 g) are treated with an equal weight of dilute nitric acid, and then thoroughly blended in a high efficiency, probe-type Polytron homogenizer; subsamples are then either dry-ashed or wet-ashed in preparation for analysis. Within-can variability is reduced from the 20—50% coefficient of variation range obtained with conventional blending procedures to a coefficient of variation of <5% by using the procedure described. Precision data for Pb, using both the probe-type and conventional blade-type homogenizers, are compared. The procedure described for Pb determination was used to analyze a number of canned products. Data indicate that the Polytron plus dilute acid procedure improves overall Pb homogeneity for subtle as well as severe initial Pb heterogeneity.
Rapid Automated Turbidimetric Assay for Chlortetracycline Hydrochloride, Using Leuconostoc mesenteroides as the Test Organism
Authors: Mueller Dorothy L , Reed Shirley J , Barkate John A
Published: February 2020

A rapid turbidimetric assay has been developed for chlortetracycline hydrochloride (CTC-HC1) in finished animal feeds and feed supplements, using Leuconostoc mesenteroides as the test organism. Two modifications are presented: The incubation period of modification 1 is 2.5 hr and the sensitivity of the assay is 0.03 μg CTC-HC1/assay tube. Modification 2 has a sensitivity of 0.01 μg CTC-HC1/assay tube and requires an incubation period of 3.5 hr. For 21 feed formulations, the turbidimetric method recovered 95.7% of label claim. Recoveries of CTC-HC1 standards from the same feeds ranged from 93.4 to 134% with a mean of 103% . The relative standard deviation among day-to-day duplicates is 3.50% for the faster modification and 1.63% for the more sensitive modification.
High Pressure Liquid Chromatographic Determination of Sugars in Various Food Products
Authors: Dunmire David L , Otto Susan E
Published: February 2020

A high pressure liquid chromatographic (HPLC) method has been developed which is fast, simple, specific, and reliable over a wide range of sugar concentrations in a variety of food matrices. With few exceptions, sample preparation is simple, requiring only a waterethanol extraction, followed by a rapid minicolumn cleanup before injection into the HPLC system. The majority of samples can be prepared for analysis within 1—1½ hr, and the following sugars are separated in <45 min: fructose, glucose, sucrose, maltose, lactose, melibiose, raffinose, and stachyose. This method is applicable to baby foods, cereals, chocolate products, chocolate sirups, cookies, health food products, molasses, preserves, processed fruits, and soy protein products.
Identification and Gas-Liquid Chromatographic Determination of Aryl Phosphate Residues in Environmental Samples
Authors: Lombardo Pasquale , Egry Ivan J
Published: February 2020

Aryl phosphates are widely used as flame retardant plasticizers and hydraulic fluids. Laboratory exposures of rainbow trout to a commercial phosphate hydraulic fluid in a flow-through system resulted in substantial biomagnification. Aryl phosphate residues in fish are extracted and cleaned up by the AOAC method for pesticides in fatty foods, and are detected by phosphorus-selective gas-liquid chromatography. Residues of several aryl phosphate mixtures were detected in fish near industrial sites at concentrations ranging from 0.04 to 1 ppm (edible portion basis).
High Pressure Liquid Chromatographic Determination of 3,5-Dimethyl-4-(Methylthio) phenyl Methylcarbamate in Formulations
Authors: Fuzesi Martha
Published: February 2020

Methiocarb (3,5 - dimethyl - 4 - (methylthio) - phenyl methylcarbamate) is extracted from commercial pesticide formulations with methanol, and carbaryl is added as an internal standard. The sample is chromatographed by reverse phase high pressure liquid chromatography, with ultraviolet detection at 254 nm. Peak height ratios are used for quantitative measurement. The method is rapid and accurate, and recoveries from laboratory-prepared formulations averaged 100.8%.
Gas-Liquid Chromatographic Method for the Analysis of Technical Dichlobenil and Its Formulations:1 Collaborative Study
Authors: Bemmel Pieter Van , Rossum Bram Van , Martijn Albertus
Published: February 2020

A gas-liquid chromatographic method for determining dichlobenil in technical material and formulations was collaboratively studied by 7 laboratories. Five samples were chromatographed on a 10% Carbowax 20M column with methyl myristate as the internal standard and flame ionization detection. The estimates of the repeatability (different analysts) and the reproducibility, expressed as coefficients of variation, were, respectively, 0.8 and 1.0% for the technical sample, 1.4 and 1.7% for the wettable powder, and 3.5 and 4.6% for the granular formulations. This method was adopted as a full CIPAC-AOAC method.
Rapid Spectrophotometric Method for Determination of Benzoic and Cinnamic Acids in Balsam Tolu
Authors: El-Masry Sawsan
Published: February 2020

A rapid spectrophotometric method is described for the individual assay of balsamic acids. The method has been applied to the determination of benzoic and cinnamic acids in samples of balsam tolu. Compared with the British Pharmaceutical Codex procedure, the recommended method combines the advantages of a faster analysis and the determination of individual balsamic acids without the need of organic solvent extraction. The sample is saponified and purified and the 2 balsamic acids are determined spectrophotometrically using the 2-wavelength method of analysis. The method has been successfully applied to the analysis of 4 batches of balsam tolu. The relative standard deviation is 1.85%.
Isolation and Concentration of Organophosphorus Pesticides from Drinking Water at the ng/L Level, Using Macroreticular Resin
Authors: Lebel Guy L , Williams David T , Griffith Georgina , Benoit Frank M
Published: February 2020

A screening method has been developed for determining organophosphorus pesticides at ng/L levels in drinking water. Sixteen organophosphorus pesticides, diazinon, diazinon-oxon, dimethoate, ronnel, β-phosphamidon, methyl parathion, ethyl parathion, malathion, chlorpyrifos, fenitrothion, ruelene, methidathion, ethion, EPN, phosalone, and phosmet, were extracted by Amberlite XAD-2 resin from 100 and 200 L drinking water previously spiked with these pesticides. The pesticides were eluted from the XAD-2 resin with acetone-hexane (15+85). The concentrated extract was analyzed by gas chromatography using a nitrogen-phosphorus selective detector and by gas chromatographymass spectrometry using selected ion monitoring. Recoveries at the 10 and 100 ng/L spiking levels were greater than 90%, except recoveries for dimethoate and phosphamidon were 37 and 42 %, respectively. The analysis of 300 L Ottawa tap water showed no detectable amounts (<1 ng/L) of any of the 16 organophosphorus pesticides.
Malt Beverages and Brewing Materials: Calculation of Carbohydrate Content and Caloric Content
Authors: West Dwight B
Published: February 2020

The American Society of Brewing Chemists (ASBS) has released one new procedure and one change in a present procedure. A new method for calculating the carbohydrate content of malt beverages, after determining the specific gravity, real extract, protein, and ash contents by AOAC methods, is presented. The method is applicable to either weight or volume amounts of malt beverages. Two changes are presented in method 10.027, caloric content of malt beverages: (1) the calorie factor for grams of ethanol is changed from 7.0 to 6.9, and (2) the ash content of the malt beverage is subtracted from the real extract before calculating the calories of the extract. The 2 changes are needed to make the caloric calculation more precise.
Flotation Technique for Quantitative Determination of Mite Populations in Powdered and Compacted Foodstuffs
Authors: Thind Bharat B , Griffiths Donald A
Published: February 2020

Samples are preheated in 25% aqueous ethanol at 65 °C for 5 min. A specially designed flotation flask and solvent mixture of kerosenetetralin (1+1) is used to form an interface with 25% aqueous ethanol. Mites, insects, and insect fragments are separated from vegetative material by an overflow method. Trials incorporating a known number of mites in samples of pigmeal indicate that at an infestation level of 1000 mites/kg the method always recovered 70% of the population and at 2000 mites/kg, 75%. The method permits collection of mite specimens for microscopic examination as well as allowing differentiation between live and long-dead insects. It does not use highly volatile solvents or corrosive acids. The apparatus has been successfully tested for quantitatively determining mite populations in flour, dried skimmed milk, animal feedstuffs, soya meal, wheat, rape seed, dates, and house dust. It has also been used to estimate insect contamination in packaged dates.
Assay of Formulations Containing 2,4-D and/or Picloram by Direct Injection High Pressure Liquid Chromatography
Authors: Stevens Timothy S
Published: February 2020

A rapid and precise fully automated, direct injection high pressure liquid chromatographic method is described for assaying liquid formulations of 2,4-dichlorophenoxyacetic acid (2,4-D) and/or picloram (4-amino-3,5,6-trichloropicolinic acid). The method is specific for the 2,4-D and picloram isomers. No sample preparation is needed, triplicate assays can be performed in 1 hr, and precision is about 1% relative at the 95% confidence level. Compounds are separated on a 9 mm id reverse phase microparticulate column with an eluant of ace* tonitrile-water (1+4) , buffered at pH 2.95. No bias was observed between this method and the official final action HPLC method for picloram and 2,4-D in picloram-2,4-D mixtures, 6.B09-6.B12.
Determination of Vitamin Bi in Pharmaceutical Preparations Using a Lead Ion Selective Electrode and Atomic Absorption Spectroscopy
Authors: Hassan Saad S M , Zaki Mohamed T , Eldesouki Mohamed H
Published: February 2020

Simple, rapid, and accurate methods have been developed for determining vitamin Bx in pharmaceutical preparations without prior separation of the vitamin. The methods are based on the desulfurization reaction with potassium plumbite and measurement of the unreacted lead (II) ions at 217 nm using atomic absorption spectroscopy (AAS), or by titration with EDTA at pH 4.5 with the lead ion selective electrode and Gran's plot. The results compare favorably with those obtained using the USP fluorometric method. Recoveries of pure vitamin Bx averaged 99.1%, with a standard deviation of 0.8%, and 99.0%, with a standard deviation of 0.7%, for the AAS and ion selective electrode procedures, respectively.
Bathocuproine Method for Determining Water-Soluble Copper in Water-Insoluble Copper Fungicides:1 CIPAC Collaborative Study
Authors: Sánchez-Rasero F , Henriet J
Published: February 2020

A spectrophotometry bathocuproine method for determining water-soluble copper in copper oxychloride and cuprous oxide was collaboratively studied by 9 laboratories. The samples are dispersed in deionized water. After centrifugation and nitration, the water-soluble copper in the nitrate is reduced to Cu+ with ascorbic acid. After the bathocuproine reagent is added, the colored complex is extracted with chloroform and its absorption is measured at 465 nm and compared to a standard calibration curve. Satisfactory results were obtained: Both the repeatability and the reproducibility standard deviations ranged from 0.002 to 0.04; the coefficients of variation ranged from 7.63 to 12.71.
Spectrophotometric Determination of Benomyl and Methyl 2-Benzimidazole Carbamate in Product Formulations by a Low Temperature-Solubilization Technique
Authors: Chiba Mikio
Published: February 2020

A rapid spectrophotometric method has been developed to determine benomyl (methyl l-(butylcarbamoyl)- 2-benzimidazole carbamate) and methyl 2-benzimidazole carbamate (MBC) simultaneously in wettable powder formulations by solubilizing all the ingredients in a special solvent mixture. A special solvent mixture consisting of chloroform, dioxane, and water was prepared at room temperature; the mixture was cooled to 1°C and used to dissolve samples. The degradation of benomyl, unavoidable at 25°C, was eliminated by this cold temperature operation. Absorbance of the diluted solution was measured at 294 and 286 nm in a ratiorecording spectrophotometer, and individual concentrations of benomyl and MBC were calculated by a simple equation. An alternative method has been suggested for users of nonautomatic scanning spectrophotometers. re-Butyl isocyanate was used to stabilize benomyl in standard solutions and to re-form benomyl from MBC. Analyses were conducted on Benlate® 50% WP and Benlate® 10% WP mixed with captan 50%. Most 50% WP formulations contained 50-55% intact benomyl and 0.4-2.3% MBC. Benomyl was stable in those WP formulations, although both time and conditions of storage varied significantly. Most 10% WP samples contained 8–12% benomyl and 0.1–2.9% MBC.
Thin Layer Chromatography Combined with Color Spot Test Reactions for Preliminary Identification of Papaveraceous Alkaloids
Authors: Engelke Beatriz Ferreira , Vincent Phillip G
Published: February 2020

Thin layer chromatography (TLC) and color spot test reagents (CSTR) were used consecutively to identify isolated papaveraceous alkaloids. Fourteen alkaloid standards were spotted on fluorescent and nonfluorescent silica gel G TLC plates and developed with 3 solvent systems. Spots were evaluated by appearance under daylight, appearance under short wavelength ultraviolet light, color developed by 2 spray reagents, and migration. Eighteen crystalline alkaloids were tested on spot plates with Frohde, Ferreira, Marquis plus oxidant, Mecke, and ferric oxidizing reagents. Colors developed were evaluated as a function of time. Color names were standardized by comparison with color plates from the Centroid Color Charts issued by the Intersociety Color Council of the National Bureau of Standards. TLC separation followed by CSTR is a useful analytical procedure for preliminary identification of alkaloids extracted from tissues of papaveraceae.
Extraction of Light Filth from Ground Nutmeg: Collaborative Study
Authors: Thrasher Joel J
Published: February 2020

The official method for extracting light filth from ground nutmeg, 44.116, gives variable recoveries of filth elements and results in large amounts of interfering plant material in the light filth extraction. A new method has been developed using a chloroform pretreatment for heavy filth followed by a water-40% isopropanol- mineral oil flotation of light filth. A comparison of the methods in the collaborative study showed a higher recovery of insect fragments, 90.6 vs. 65.2%, and of rodent hairs, 86.5 vs. 66.5%, for the new method over the present official first action method, 44.116. Frothing, an additional problem with the official method, has been reduced by the new method. The new method has been adopted as official first action to replace the existing method.
Fish Species Identification by Thin Layer Isoelectric Focusing
Authors: Lundstrom Ronald C
Published: February 2020

Conventional electrophoretic techniques generally lack the resolution and reproducibility needed for the reliable identification of fish species. Variations in stabilizing media composition, sample application technique, separation time, applied voltage or current, and the analyst’s skill all affect the protein pattern. Thin layer polyacrylamide gel isoelectric focusing (TLIEF), a high resolution protein separation technique, has been applied to the identification of fish species. Sarcoplasmic proteins are separated according to their isoelectric points in a stable, reproducible ptT^gradient. Protein patterns for 12 species of fish are compared in 4.0% polyacrylamide gels with pH 4.0–6.0 and pH 3.5–10 gradients. Similar patterns are shown in commercially prepared 5.0% polyacrylamide gels with pH 4.0–6.5 and pH 3.5–9.5 gradients (LKB PAG plates). The protein patterns are reproducible in each pH gradient and also correlate well between user-prepared and commercially prepared gels. The inherent high resolution and excellent reproducibility of TLIEF should allow the positive identification of fish species without the costly procedure of using known species as standards.
Determination of Chlorinated Pesticide Residues in Foods. I. Rapid Screening Method for Chlorinated Pesticides in Milk
Authors: Suzuki Takashi , Ishikawa Kiyoshi , Sato Nobutoshi , Sakai Kei-Ichi
Published: February 2020

A rapid analytical method for determining chlorinated pesticide residues in milk was developed. Thirteen pesticides were almost completely extracted. Ten mL samples of fortified milk were extracted 3 times with 20 mL portions of n-hexane as follows: (A) in the absence of water-soluble solvent; in the presence of (B) 1 mL acetonitrile; (C) 3 mL acetonitrile; (D) 5 mL acetonitrile; (E) 5 mL ethanol; (F) 5 mL acetonitrile and 1 mL ethanol. System F produced the highest pesticide recoveries but the lowest fat extraction, thus eliminating the necessity for liquid-liquid partitioning and minimizing Florisil column cleanup. Pesticide recoveries throughout the procedure were 94– 103%. It was noticed, however, that the fat in high fat-containing raw milk is more readily extracted than that in commercial milk. Although a number of rapid methods
Identification of Canned Salmon Species by Scale Characteristics
Authors: Newton Richard T
Published: February 2020

A modified method and key for the identification of canned salmon species have been subjected to an additional collaborative study. Of 54 samples examined, 11 collaborators accurately identified 10 of 10 samples (100%) of sockeye, 11 of 11 samples (100%) of chum, 11 of 11 samples (100%) of pink, 11 of 11 samples (100%) of coho, and 11 of 11 samples (100%) of chinook. Nine of 11 collaborators were able to find in all samples usable scales with intact clear areas for mounting and identification. Two of the 11 had a minor problem. The improved, modified method and key have been adopted as official first action for the identification of the sockeye, chum, pink, coho, and chinook salmon species to replace method 18.089.
Gas-Liquid Chromatography of Bolstar Formulations
Authors: Boyd Willard G
Published: February 2020

A simple and rapid gas-liquiJ chromatographic method for assaying Bolstar formulations is described. Flame ionization detection, a column packed with SE-30/OV-210 on Gas-Chrom Q, and on-column injection are specified. Tetracosane internal standard in benzene is added to the weighed sample, and integratorarea ratios are used for quantitative measurement. The integrator response ratio of Bolstar area to tetracosane internal standard area, plotted against Bolstar concentration, is linear over a 2.85–7.78 mg/mL range. A technical material, a synthetic formulation, and 4 commercial formulations of Bolstar were assayed with good precision. Three assays of technical material against 3 standard weighings gave a coefficient of variation of 0.479%. Eight assays of a synthetic sample formulation, containing 63.86 theoretical per cent Bolstar, yield an average of 63.81% Bolstar with a coefficient of variation of 0.213%. Two assays each of 4 commercial Bolstar formulations gave an average coefficient of variation of 0.280%. Statistical analysis of 12 integrator response ratios, standard area to internal standard area, for 1 set of analyses gave a coefficient of variation of 0.322%.
Flameless Atomic Absorption Spectrophotometric Determination of Vendex, an Organic Tin Miticide, in Apples, Oranges, and Tea Leaves
Authors: Sano Mitsuaki , Furukawa Masako , Kourai Miyako , Tomita Isao
Published: February 2020

A method is described for the determination of an organic tin insecticide, Vendex or hexakis(2-methyl-2-phenylpropyl)distannoxane (HMPD). Tin compounds are extracted from the sample homogenate with ethyl ether containing 1% acetic acid. HMPD and its degradation products are separated through a silica gel column, and analyzed by an atomic absorption spectrophotometer coupled with a heated graphite atomizer. By this technique, as little as 5 ng HMPD and its degradation products can be determined with an average recovery of 67–96%.
Quantitative Confirmation of Dimethoate Residues in Wheat Plants by Single Ion Mass Spectrometry
Authors: Lee Young W , Westcott Neil D
Published: February 2020

A gas chromatographic-single ion mass spectrometric method was developed for determining dimethoate residues in wheat plants. The base peak (m/e 87) of dimethoate was chosen as the single ion peak, and methyl stearate was used as an internal standard for this analysis. The minimum detectable concentration of dimethoate by this method was about 0.1 ppm for a 20 g wheat plant sample. The recoveries of dimethoate were about 89% at 0.13 ppm and >96% at 0.5-1 ppm.
Identification Tests for Propantheline Bromide
Authors: Brannon Wilson L , Benson Walter R , Smith Myron M
Published: February 2020

A method is described for the isolation and identification of propantheline bromide from bulk drug substances and dosage forms, both alone and in combination with other drug sub-stances. The method permits the specific identification of the intact drug substance, using both infrared spectroscopy and thin layer chromatography.
Reverse Phase High Pressure Liquid Chromatographic Determination of Some Iodoamino Acid Contaminants in Sodium Liothyronine or Sodium Levothyronine
Authors: Smith Donald J , Graham Joseph H
Published: February 2020

Some iodoamino acids have been separated and determined by high pressure liquid chromatography on octadecylsilane reverse phase packing with a mobile phase consisting of methanol, potassium phosphate monobasic, and orthophosphoric acid at 44°C. The method separates and quantitates mixtures of 3,5-diiodothyronine, liothyronine, isoliothyronine, and levothyroxine. The procedure provides an accurate, sensitive, and rapid estimation of decomposition and/or impurities in standards in approximately 30 min, at the <75 pmole level, using an ultraviolet detector at 254 nm.
Microbiological Assays for Antibiotics and Vitamins: Considerations for Assuring Accuracy
Authors: Kavanagh Frederick , Ragheb Hussein S
Published: February 2020

Factors that may influence the accuracy and precision of microbiological manual and semiautomated turbidimetric methods as well as diffusion assays are discussed. Influence of kind of equipment, media, test bacteria, sample preparation, form of dose response lines, operations, and personnel on quality of assays is examined with the objective of reducing to insignificance those factors under control of the analyst that are responsible for low quality assays.
High Pressure Liquid Chromatographic Determination of Chlorophacinone in Formulations
Authors: Grant Ralph G , Pike Richard K
Published: February 2020

A simple and rapid method is described determining for 2- ((p-chlorophenyl) phenylacetyl-1,3- indandione (chlorophacinone) in rodenticides formulated as tracking powders and whole grain and crushed grain baits. The bait is extracted with methanol containing an internal standard, and the extract is injected into a high pressure liquid chromatograph. The sample is analyzed by reverse phase chromatography on octadecyl (C18) bonded to glass beads with a mobile phase of methanolwater (35+65) plus 0.75% NH4OH. A 5 μL injection containing 240 ng benzophenone internal standard and 77 ng chlorophacinone produces half scale peaks at 280 nm with a full scale absorbance of 0.01 absorbance unit. Two formulations and a spiked sample were analyzed by the method. Recovery as determined by peak area was >97%.
Gas-Liquid Chromatographic-Mass Spectrometric Determination of α- and β-Naphthylamines in FD&C Red No. 2 (Amaranth)
Authors: Stavric Bozidar , Klassen Raymond , Miles Walter
Published: February 2020

A method is described for the simultaneous quantitation of trace amounts of α- (α-NA) and β-naphthylamines (β-NA) with detectability in the 0.1 ppb range and sensitivity of 50 picomoles in certified food grade amaranth (FD&C Red No. 2; C.I. Food Red 9; CI 16185). The amaranth sample is extracted with benzene, and the evaporated residue is derivatized with perfluorooctanoic anhydride. The resulting derivatives are separated by gas-liquid chromatography and identified and quantitated by mass spectrometric monitoring of the m/e at 539.04. The method was used for quantitation of α-NA and β-NA in randomly chosen samples of amaranth. Of 11 samples from different manufacturers, 5 were free of the β-isomer; the remaining samples contained up to 1.2 ppb β-NA. The concentration of α-NA ranged from no detectable amount to 970 ppb; the majority of the samples contained less than 7 ppb.
Microdetermination of Naphthionic Acid in Serum and Amniotic Fluid
Authors: Stavric Bozidar , Craig Jane , Klassen Raymond , Willes Robert
Published: February 2020

A simple, rapid, sensitive, and reproducible microdetermination of naphthionic acid (NA) in serum and amniotic fluid is described. The detection limit of the method is 1 ng NA in 20 μL serum, and 3 ng NA in 50 μL amniotic fluid. The concentration of nonderivatized NA was measured by fluorescence spectrophotometry (excitation 328 nm, emission 420 nm) of the supernate, after precipitation of proteins with absolute ethanol and heating for 30 min at 75°C. Standard deviations of determinations for 2, 10, and 50 ng NA in 20 μL serum were 10.1, 7.59, and 7.64%, respectively. An analyst can perform about 100 determinations daily; results are available within 2 hr of sampling. A modification of the procedure to permit quantitation of NA in urine is also described.
Deep Solvent Trough for Thin Layer Chromatography
Authors: Trucksess Mary W , Stoloff Leonard
Published: February 2020

A deep solvent trough for thin layer chromatography is described. By use of this device a second development of a thin layer plate containing slow moving background compounds can be made without interference from these compounds when the solvent polarity is increased. A score line across the plate, separating the compounds of interest from the background, in combination with a solvent depth that bridges the score line, results in interference-free secondary development and reduced development time.
High Performance Liquid Chromatographic Determination of Nine Phenolic Antioxidants in Oils, Lards, and Shortenings
Authors: Page B Denis
Published: February 2020

A simple, rapid technique is described for the determination of 2- and 3-tert-butyl-4-hydroxyanisole (BHA), tert-butylhydroquinone (TBHQ), 3,5-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butyl-4-hydroxymethylphenol (Ionox-100), 2,4,5-trihydroxybutyrophenone (THBP), propyl gallate (PG), octyl gallate (OG), dodecyl gallate (DG), and nordihydroguaiaretic acid (NDGA) in vegetable oils, lards, and shortenings. The antioxidants are partitioned from hexane-oil into acetonitrile, concentrated under vacuum, and determined by reverse phase, gradient elution, high performance liquid chromatography with detection at 280 nm. The mobile phase is wateracetonitrile with 5% acetic acid. With this system, only Ionox-100 and OG are not resolved. Recoveries from soya-sunflower seed oil spiked at 16 and 100 ppm and from lard at 32 ppm for 8 of the 9 antioxidants ranged from 96 to 103%, 100 to 102%, and 98 to 102%, respectively. The recoveries of BHT, due to incomplete extraction, were 84, 85, and 87%, respectively.
Analytical Reference Materials. II. Preparation and Sample Integrity of Homogeneous Fortified Wet Sediment for Polychlorinated Biphenyl Quality Control Studies
Authors: Chau Alfred S Y , Carron John , Lee Hing-Biu
Published: February 2020

A simple method fox the preparation of a large quantity of homogeneous wet sediment spiked with polychlorinated biphenyls (PCBs) is presented. By using a large blender and adding water to form a thick slurry, more than 2 kg spiked wet sediment was homogenized and 100-200 subsamples of 10-15 g, each suitable for checking precision and accuracy of a method or a laboratory, could be obtained. Eighteen Lake Ontario sediment subsamples were analyzed to check homogeneity. The mean recovery was 97.9% for a 1:1 mixture of Aroclors 1254 and 1260 fortified at 1 ppm; the coefficient of variation was 5.4%. For the Georgian Bay sediment, recovery for 5 replicates was 97.8% with a coefficient of variation of 3.2% for the same Aroclor mixture fortified at 0.629 ppm. Subsamples stored at — 20°C for up to 3 months showed no losses of PCBs for these 2 sediments. Stability data also provided additional support for the homogeneity of the subsamples for these 2 sediments.
Screening Method for Vitamins A and D in Fortified Skim Milk, Chocolate Milk, and Vitamin D Liquid Concentrates
Authors: Henderson Susan K , Mclean Lucia A
Published: February 2020

Vitamin A was determined in fortified chocolate milk and skim milk; vitamin D was determined in fortified chocolate milk, skim milk, and vitamin D concentrates, using reverse phase high pressure liquid chromatography (HPLC). The sample is saponified, extracted with hexane, and chromatographed in an HPLC system on a 10 μm Vydac TP reverse phase C18 column, using acetonitrile-methanol (9+1) as the mobile phase. For 6 replicates, the recoveries of vitamins A and D, using this procedure, were 99 and 98%, respectively.
Distribution of Aflatoxins B1 and M1 in Contaminated Calf and Pig Livers
Authors: Stoloff Leonard , Trucksess Mary W
Published: February 2020

The determination of aflatoxins B1 and M1 in multiple sections of livers from 4 calves and 1 pig exposed to high levels of aflatoxins showed a uniform distribution of the aflatoxins in each liver, within the precision of the analytical method used. The thin layer chromatographic method has an expected within-laboratory coefficient of variation of 15%.
Thin Layer Densitometric Determination of Gallic Acid and Gallotannins in Wine and Cider
Authors: Dadic Miroslav , Van Gheluwe Joris E A , Weaver Robert L
Published: February 2020

Free gallic acid and total gallotannins are determined in wine and cider by thin layer densitometry. The beverage is extracted with ethyl acetate and the extract is subjected to thin layer chromatography on silica gel. After elution with chloroform-ethyl formate-formic acid (50+40+ 10), the dry plate is sprayed uniformly with a freshly prepared solution of 0.3% aqueous FeCl3 and 0.3% aqueous K3FeCN6. If the gallic acid spot appears (Rf 0.28), densitometry readings are taken at 600 nm, and free gallic acid (GAF) is calculated from the formula GAF = GA (μg, from calibration curve) × 1.25. The calibration curve was obtained by plotting thin layer densitometric readings at 600 nm (prussian blue) vs. μg gallic acid. In a second method, the beverage is hydrolyzed, and extraction and densitometry are performed as before to give “total gallic acid after hydrolysis:” GAH (mg/L) = GA (μg, from calibration curve) × 25. Total gallotannins (GALLT) are calculated from the formula: GALLT (mg/L) = GAH – GAF. Results for 10 wines and 5 ciders are presented and briefly discussed.
Gas-Liquid Chromatographic Determination of Dioxathion and Quintiofos in Organophosphorus Dip Washes
Authors: Keating Molly I
Published: February 2020

A rapid method for the analysis of dip washes is described which eliminates the usual solvent extraction procedure. The dip wash is initially diluted with acetone and then with petroleum ether. The diluted dip wash is analyzed by gasliquid chromatography, using an alkali ionization detector sensitive to phosphorus compounds. The method was applied to the determination of dioxathion (2,3-ρ-dioxanedithiol S,S-bis(O,O-diethyl phosphorodithioate)), and quintiofos (O-ethyl O-8-quinolyl phenylphosphonothioate) dip washes. Average recoveries from fouled dip washes were 100 and 104%. GLC of these compounds with an internal standard is described, which improves the precision of the method to ±2%.
High Performance Liquid Chromatographic Determination of Bendiocarb on Wool
Authors: Zehner James M , Simonaitis Richard A , Bry Roy E
Published: February 2020

A high performance liquid chromotographic method is presented for determining bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl methylcarbamate) on wool. Bendiocarb is extracted from wool with methanol containing methyl benzoate as internal standard, eluted through a Zorbax ODS column with methanol-water (55 + 45), and detected with a UV detector at 280 nm. The method can be used to determine bendiocarb at 0.001–0.02% by weight. The limit of detection is 0.0004%, or 4 ppm. At 4 analyses each, recovery at 0.013% was 101%, standard deviation 2.8%; at 0.003%, recovery was 96%, standard deviation 5.6%; at 0.001%, recovery was 103%, standard deviation 2.9%.
Extraction of Pentachlorophenol and Tetrachlorophenol Residues from Field-Contaminated Carrots and Potatoes: Comparison of Several Methods
Authors: Bruns Gary W , Currie Robert A
Published: February 2020

A number of solvent extraction systems were investigated for their efficiency in removing residues of pentachlorophenol (PCP) and tetrachlorophenol (TCP) from field-contaminated carrots and potatoes. Greatest numerical yields of PCP and TCP, for both carrots (9 and 5 ng/g, respectively) and potatoes (147 and 11 ng/g, respectively), were obtained by Soxhlet extraction with acidified acetone for 44 hr. Within the limits of experimental error, equivalent results could be obtained by using a 20 hr Soxhlet extraction with acidified acetone for carrots, and a 5 min blending with acidified acetone for potatoes. Extracts were reacted with diazoethane to form the ethyl ethers of PCP and TCP, followed by cleanup on a Florisil column. A gas-liquid chromatograph equipped with a 63Ni linearized electron capture detector was used for identification and quantitation.
The AOAC: Expanding Horizons
Authors: Schall Elwyn D
Published: February 2020

A review of presidential addresses of the past reveals a fair amount of agonizing at this time of the year as the outgoing President searched for relevant, or even sparkling, comments to pass along to the membership. This year has been no exception!
Container-Derived Contamination of Maple Sirup with Methyl Methacrylate, Toluene, and Styrene as Determined by Headspace Gas-Liquid Chromatography
Authors: Hollifield Henry C , Breder Charles V , Dennison John L , Roach John A G , Adams William S
Published: February 2020

Samples of maple sirup and associated plastic packaging were examined for the presence of methyl methacrylate, toluene, and styrene by a head space gas chromatographic procedure. The volatile components common to the sirup and the plastic container were identified by gas chromatography-mass spectrometry. The quantities of these contaminants in the sirup were determined at ppb levels by the standard additions technique and repetitive headspace analysis.
Mass Loss on Drying for Instant Coffee: Collaborative Study
Authors: Clinton William P , Manni Paul H , Ferry John M
Published: February 2020

A collaborative study was undertaken to define an acceptable routine working method for determination of mass loss in instant coffee. Fourteen laboratories of 24 invited to participate submitted results. The repeatability standard deviation and coefficient of variation were 0.026 and 0.7%, respectively. The reproducibility standard deviation and coefficient of variation were 0.153 and 3.8%, respectively. The method has been adopted as official first action.
Survey for Aflatoxins and Zearalenone in Canned and Frozen Sweet Corn
Authors: Stoloff Leonard , Francis Octave J
Published: February 2020

Aflatoxins and zearalenone were determined in 263 samples of canned or frozen sweet corn, collected from packing plants during the 1976 and 1977 packing seasons. As anticipated from geographic, agronomic, and microbiological considerations, no aflatoxin or zearalenone was found. Based on this sampling, the highest incidence of detectable aflatoxin that could be statistically anticipated in the major packing areas is 1.5%.
Coprecipitation of Heavy Metals Directly in Graphite Crucibles for Furnace Atomic Absorption Spectrometry
Authors: Nichols John A , Woodriff Ray
Published: February 2020

A rapid, direct method is described for separating trace heavy metals from excessive quantities of matrix constituents for analysis of digested biological materials by furnace atomic absorption spectrometry. The analytes are coprecipitated with ammonium pyrrolidinecarbodithioate and collected on a porous graphite filter medium which is suitable, after a brief drying step, for direct insertion into an electrothermal atomizer. A constant-temperature furnace is used to verify collection efficiency of the micro-scale procedure for cadmium, copper, and zinc, and to examine the procedural criteria necessary for accurate results. The procedure is very rugged with respect to precipitation variables, and only slightly sensitive to possible gas-phase chemical interferences during atomization at sub-optimal temperatures. Thus, the procedure should eliminate matrix interferences during analysis of complex samples with a carbon rod atomizer. Direct insertion minimizes blanks, avoids resolubilization problems, and allows rapid handling of large numbers of samples.
Sensitive Gas-Liquid Chromatographic Method for Asulam Residues in Peaches
Authors: Bardalaye Promode C , Thompson Neal P , Carlson David A
Published: February 2020

The current analytical method for determining residues of the herbicide asulam (methyl (4-aminobenzenesulfonyl) carbamate) is the nonspecific colorimetric procedure based on the coupling reaction of N-1-naphthylethylenediamine with the diazotized amine. A new analytical method for determining the residues of this herbicide and its 2 known major metabolites, acetylasulam and sulfanilamide, in peaches has been developed and evaluated using gas chromatography with an N-P detector. The method is based on the hydrolytic conversion of the parent compound and the known metabolites to the common product sulfanilamide which is then analyzed by gas-liquid chromatography as its per N-methylated derivative. The identity of the derivative has been confirmed by chemical ionization mass spectrometry. The method was tested by using fortified crop extracts and also by analyzing crop treated by postemergent application of the herbicide for weed control. Sensitivity of the method is 5 ng and the detection limit in the crop is 0.1 ppm. Recoveries ranged from 70 to 80% from peaches at fortification levels of 1, 5, and 10 ppm. At a fortification level of 0.1 ppm the recovery is 50-60%.
Modification of the AOAC Method for Determination of Fumigants in Wheat
Authors: Jr Marion Clower
Published: February 2020

The official first action AOAC method for determination of residues of fumigants in grains has been modified for use by 6 laboratories in an FDA pesticide surveillance program. A 15% OV-I7 gas-liquid chromatographic column, installed in a chromatograph equipped with a constant current 63Ni electron capture detector, provides for improved resolution, multiresidue capability, and lower limits of detection. A study was made of the behavior of chloroform, carbon tetrachloride, ethylene dichloride, trichloroethylene, tetrachloroethylene, and ethylene dibromide through the method. Recoveries from fortified wheat samples averaged 105-115%. Experimental evidence is presented which suggests that part of the consistent trend toward high recovery can be attributed to selective sorption of acetone by the CaCI2 used in the final drying step.
Determination of Aflatoxins in Compound Feedstuffs Containing Citrus Pulp
Authors: Jain Anant V , Hatch Roger C
Published: February 2020

A method is described for determining aflatoxins B1, B2, C1, and G2 in compound feedstuffs containing citrus pulp. A finely ground sample is extracted with methylene chloride in a blender and cleaned with lead acetate. An aliquot of the cleaned extract is partitioned into methylene chloride and evaporated to dryness. The residue is dissolved in 0.5 mL chloroform. A 10 μL sample is applied to a thin layer chromatographic (TLC) plate and developed in 2 dimensions. Aflatoxins B1( B2, G1, and G2 are resolved and quantitated visually. The average recoveries were 96, 104, 98, and 102%, respectively. As little as 5 μg aflatoxin B1, or G1/kg, and 1.5 μg aflatoxin B2 or G2/kg can be determined by this procedure.
Modification of Official Method for Analysis of Carotenes and Xanthophylls in Dried Plant Materials and Mixed Feeds
Authors: Gimeno Alberto
Published: February 2020

The official method (43.018–43.023) for extraction and separation of carotenes and xanthophylls in dried plant materials and mixed feeds is modified. These pigments are extracted from samples lacking xanthophyll esters by stirring 2 hr, followed by 1-hr cold saponification. The official method recommends 16-hr static extraction preceding the cold saponification. For samples containing xanthophyll esters, we preceded the 20-min hot saponification step by 2 hr stirring. This extra step increased the yield of mono- and dihydroxy pigments, especially from marigold meal. For separation, Merck silica gel 60 plus Hyflo Supercel is substituted for silica gel G in adsorbent I, resulting in 30-min separation. Also, at least 4 separations can be performed using the same adsorbent, and the column is more easily cleaned between separations. Results of the modified method were comparable to those of the official method.
High Pressure Liquid Chromatographic Determination of Sorbitol in Bulk Sorbitol
Authors: DOkladalova J , Barton A Y , Mackenzie E A
Published: February 2020

An HPLC procedure for determining sorbitol in bulk sorbitol is described. An Aminex HPX-87 column (Bio-Rad) is used with water as a mobile phase and with a refractive index detector to monitor column eluate. Sorbitol is separated from pentaerythritol, erythritol, ribitol, ethylene glycol, propylene glycol, arabitol, galactitol, mannitol, iditol, and other carbohydrates. The precision of the sorbitol determination, characterized by a 95% confidence interval, corresponds to ±1.22%.
Rapid Method for Extraction and Colorimetric Estimation of Morphine in Indian Opium
Authors: Vaidya Prabhakar V , Pundlik Mukund D , Meghal Sharadchandra K
Published: February 2020

A rapid method for the extraction and estimation of morphine in Indian opium is described. Methanolic extract of opium is treated with activated charcoal and the colorless extract obtained contains all of the major opium alkaloids. Morphine content is estimated colorimetrically by using hydrogen peroxide–copper–ammonia. The reaction is specific for morphine, and no other major opium alkaloid responds. The results obtained by the proposed method are in general agreement with those obtained by the nitroso method.
Reverse Phase Thin Layer Chromatographic Procedure for Identification of Digoxin and Related Fluorescing Substances
Authors: Bloch Doris E
Published: February 2020

A one-step method was developed to replace the current USP monograph procedures for identification of digoxin and determination of related fluorescing substances. The new method is much quicker than the previous tests, which required paper chromatography and fluorometric measurements, respectively. Using reverse phase silica gel plates (C18 bonded to silica gel), digoxin was separated from digitoxin, gitoxin, and digoxigenin mono-digitoxoside, and partially resolved from digoxigenin bis-digitoxoside. A digoxin reference standard is used to correlate Rf values for identification, and a dilute solution of gitoxin is also co-spotted to give a maximum intensity limit for related fluorescing substances.
Comparison of Three Sample Preparation Techniques for Determination of Organic Bromide and Chloride in Halogenated Lipids by X-Ray Fluorescence Spectroscopy
Authors: Conacher Henry B S , Chadha Rajinder K , Lacroix Gladys
Published: February 2020

Three sample preparation techniques—thin-film, solution, and cellulose pellet—were applied to the determination of bromide in brominated lipids by X-ray fluorescence spectroscopy. Using brominated vegetable oils of known bromide content it was demonstrated that the thin-film technique could result in erroneously high bromide contents, which could also vary with the amount of oil applied, depending on the solvent used. As solutions in hexane, slightly high bromide contents were observed at high concentrations. With the cellulose pellets, bromide contents similar to known values were observed. It was concluded that the cellulose pellet procedure, although more time consuming, and less convenient for ready recovery of sample, was the most suitable for organic bromide determination. Similar results were indicated for chlorinated oils.