bluuebunny/crossref_metadata_2025 huggingface dataset:
Banminth and a Common Fragment Assay
Authors: Figdor Sanford K , Von Wittenau M Schach , Lynch Martin J
Published: February 2020

The metabolism of the anthelmintic pyrantel, Banminth™ (trans-l-methyl-l,4,5,6-tetrahydro- 2-[2-(2-thienyl)vinyl]pyrimidine) is characterized by extensive transformations. Evidence derived from excreted metabolites indicated nearly total destruction of the thiophene ring. The tetrahydropyrimidine moiety was less extensively degraded since the basic skeleton, iV-methylpropanediamine, was obtained after hydrolysis. In addition, some of the pyrantel radioactivity was degraded to small fragments and re-incorporated into normal tissue constituents since liver amino acids gave 14C02 after ninhydrin treatment. Attempts to develop a tissue residue assay involved the difficult task of distinguishing drug-related front tissue re-incorporated radioactivity in the parts per million range. An approach to choosing a marker residue was to select a feature common to the metabolites present in tissues, chemically liberate that entity, and designate it the marker residue. The tetrahydropyrimidine portion of pyrantel offered such an opportunity since N-methylpropanediamine was readily liberated by hydrolysis. It was demonstrated that approximately half of the radioactivity in long-term tissues was associated with N-methylpropanediamine and that the remainder of tissue radioactivity was re-incorporated label. Thus, for assay purposes, the hydrolysis of tissue followed by the quantitation of N-methylpropanediamine served as a useful procedure that permitted monitoring a number of drug-related residues which still contain the diamine moiety.
Comparison of Two Rapid Test Procedures with the Standard EC Test for Recovery of Fecal Coliform Bacteria from Shellfish-Growing Waters
Authors: Hunt Daniel A , Springer Janet
Published: February 2020

A study was conducted to compare recovery and enumeration capability of two 24-hr multitube fermentation tests with the standard EC test for fecal coliform levels in shellfish-growing waters. The 2 tests were the A-1 test developed by Andrews and Presnell, specifying 24-hr incubation in A-1 medium at 44.5CC; and a modification of the A-1 test requiring a 3-hr resuscitation at 35°C before incubation at 44.5°C for 21 hr. Fifteen State, Federal, and Provincial laboratories examined 10 routine shellfish-growing area samples per month in parallel by the 3 methods for 1 year. IMViC tests (indole, methyl red, Voges-Proskauer, and citrate) were conducted on all gas-positive tubes. The modified A-1 test recovered higher levels of fecal coliforms than the A-1 test. Although there were seasonal and geographic variations in recovery and enumeration by the modified A-1 test, overall there was good correlation of the modified A-1 test with the EC test. Both the A-1 and modified A-1 tests were more specific for Escherichia coli than the EC test. Results of the study indicate that the 24-hr modified A-1 test can be used as an alternative test for the standard 72-hr EC test as an adjunct to the sanitary survey for the classification and control of shellfish-growing area waters.
Improved Colorimetric Method for Determining Nitrate and Nitrite in Foods
Authors: Sen Nrisinha P , Donaldson Barbara
Published: February 2020

A method is described for determining nitrate and nitrite in cured meat products, cheeses, and vegetables. The nitrite is determined colorimetrically by diazotization of sulfanilic acid and subsequent coupling with N-(l-naphthyl)-ethylenediamine. The concentration of nitrate plus nitrite is determined similarly but after reduction of the nitrate to nitrite on a cadmium column. The difference of the 2 values is a measure of the nitrate concentration. The main improvements are replacing the Griess reagent, which contains a carcinogen, with a mixture of sulfanilic acid and N-(l-naphthyl)- ethylenediamine, providing for adjustment of pH of the sample suspension during extraction and digestion by heating, and maintaining constant pH by controlled addition of buffers and acids during color development. The method was successfully applied to the analysis of 15 samples of meat products, 23 cheeses, and 6 different vegetables. The average recovery of sodium nitrite added at levels ranging from 10 to 30 ppm was 9 5% and recovery of sodium nitrate added at levels from 30 to 400 ppm was 9 4% (corrected for cadmium column efficiency).
Two Lipoxidase Methods for Measuring cis,cis-Methylene Interrupted Polyunsaturated Fatty Acids in Fats and Oils : Collaborative Study
Authors: Sheppard Alan J , Waltking Arthur E , Zmachinski Helen , Jones Shirley T
Published: February 2020

Two methods for measuring the cis, cis methylene interrupted polyunsaturated fatty acids (cis, cis-PUFA) content of fats and oils were compared collaboratively. The methods evaluated were one proposed by the Food and Drug Administration (Method I) and one used by industry (Method II). Analyses of variance between methods and samples and between laboratories and methods showed similar select differences significant at the 95% level (P < 0.05) for both methods. The reproducibility standard deviations were lower with Method II for 3 of the 5 samples, but equally higher than with Method I for 2 other samples. The repeatability standard deviation for one of the oils was significantly higher for Method II but were significantly higher for Method I for 2 other oils. Over all of the samples, the 2 methods gave similar results and there was no overall statistical difference in the performance.
High Pressure Liquid Chromatographic Determination of Atropine Sulfate and Scopolamine Hydrobromide in Tablets
Authors: Walters Milda J
Published: February 2020

A reverse phase high pressure liquid chromatographic (HPLC) system utilizing ion-pairing, similar to that previously reported for methscopolamine bromide, was developed for the quantitation of atropine sulfate and scopolamine hydrobromide in tablets. This HPLC system is capable of differentiating the major tropane alkaloids, with the exception of the atropine- hyoscyamine optical isomer pair, by their k' values and separating a significant degradation product, tropic acid. Optimum sensitivity is obtained by using a variable wavelength ultraviolet detector at 230 nm resulting in a detection limit of < 0.5 μg alkaloid/injection. The response is linear in the range of 3–19 ---g atropine sulfate and scopolamine hydrobromide. The coefficient of variation for injection reproducibility is < 1 %. The method has been applied to composite and individual tablet assays of scopolamine hydrobromide and atropine sulfate. The HPLC results are comparable (within 1%) to those obtained using the USP procedure; the HPLC method requires less sample preparation.
High Pressure Liquid Chromatographic Determination of Rotenone and Degradation Products in Animal Chow and Tissues
Authors: Bowman Malcolm C , Holder Claude L , Bone Larry I
Published: February 2020

An analytical procedure is described for determining residues of rotenone, rotenolone, dehydrorotenone, and rotenonone in admixture in animal chow and tissues. The methanol or ethyl ether extracts from samples of chow and tissues, respectively, are subjected to a liquidliquid partitioning cleanup with hexane-acetonitrile, further cleanup on a column of silica gel, and subsequent analysis by high pressure liquid chromatography using an ultraviolet absorption detector set at 295 nm. Animal chow, mouse fetuses, and gastrointestinal tracts spiked with 0.5 ppm of each compound in admixture yielded average recoveries of 92, 51, and 79%, respectively; minimum quantities of the 4 compounds detectable in the 3 substrates averaged 0.12, 0.04, and 0.14 ppm, respectively. Stability studies indicate that rotenone reacts with animal chow with a half-life of 7–8 days and is photodegraded in incandescent light with a half-life of 0.65 day. No transplacental transfer of rotenone or its products was observed in fetuses from mice receiving 7 consecutive daily doses of rotenone at levels up to 25 mg/kg.
Gas-Liquid Chromatographic Determination of Sodium 5- [2-Chloro-4- (trifluoromethyl) phenoxy] -2-nitrobenzoate Residues on Soybeans and Foliage, Soil, Milk, and Liver
Authors: Adler Irving L , Augenstein Larry L , Rogerson Thomas D
Published: February 2020

Residues of sodium 5- [2-chloro-4-(trifluoromethyl) phenoxy] -2-nitrobenzoate and its free acid are determined by treating a sample extract with diazomethane to convert the residues to methyl 5- [2-chloro-4-(trifluoromethyl)phenoxy] -2-nitrobenzoate. This compound is purified by chromatography on Florisil and measured by electron capture gas-liquid chromatography. The method has been used on soybeans, soybean foliage, soil, milk, and liver. It can detect 0.01 ppm with recoveries of 70–75%.
Confirmation of Pesticide Residues Identity. X. Mirex
Authors: Chau Alfred S Y , Carron John M , Tse Hung
Published: February 2020

Three procedures using 3 different ratios of chromous chloride and acetone at room temperature or 55–60°C are described for confirming the presence of Mirex (dodecachlorooctahydro- l,3,4-metheno-2H-cyclobuta [cd] pentalene). Each procedure gives a different major product with a different gas-liquid chromatographic retention time. The factors that could affect this reductive dechlorination were also studied. The procedures can detect, respectively, 1.1, 0.7, and 0.5 times the amount of the Mirex standard (taken as 1.0) used in the investigation.
Investigation of the Integrity of Seven Herbicidal Acids in Water Samples
Authors: Chau Alfred S Y , Thomson Karen
Published: February 2020

The stability of the following 7 herbicidal acids in distilled water and natural water preserved with sulfuric acid was investigated: 2,4-D, 2,4-DB (4-(2,4-dichlorophenoxy)butyric acid), 2,4-DP (2-(2,4-dichlorophenoxy)propionic acid), dicamba, MCPB (2-methyl-4-chlorophenoxyacetic acid), silvex, and 2,4,5-T. None of the acids showed detectable degradation in distilled water up to the 40 day period of investigation or in Hamilton Harbour water up to the 50 day period of investigation.
Analysis of Chloroxuron Technical and Its Formulations: Collaborative Study
Authors: Heizler Werner , Meier Juerg , Nowak Klaus , Suter Rolf , Bosshardt Hans P
Published: February 2020

Chloroxuron technical and its 50% wettable powder were analyzed by 17 participants in a CIPAC collaborative study. The analytical method used involves acid extraction to remove interfering free amines, followed by alkaline hydrolysis of the extraction residue, distillation, and titration of the liberated dimethylamine. Related byproducts which may interfere are determined by semiquantitative thin layer chromatography. Results obtained from 17 government and industrial collaborators showed good repeatability within laboratories. Good agreement was also achieved between laboratories. A reproducibility of about 1.5% was obtained. The method has been adopted as an interim official CIPAC-AOAC method.
Colorimetric Determination of Carbofuran in Formulations
Authors: Handa Swadesh K , Dikshit Anand K
Published: February 2020

Carbofuran formulations are cleaned up by thin layer chromatography to separate possible interferences from carbofuran. Carbofuran phenol is reacted with vanillin to form a colored compound with an absorption maximum at 550 nm. The relationship between absorbance and concentration of carbofuran is linear from 5 to 50 μ5 ml solution. Recoveries of carbofuran from laboratory-prepared formulations ranged from 98.0 to 98.93%.
Determination of Amitraz in Cattle Dipping Baths and Sprays
Authors: Machin Michael V , Mcdougall Kerryn W
Published: February 2020

Infrared (IR) and gas chromatographic methods have been developed for determining the acaricide amitraz (N-(2,4-dimethylphenyl)-N - [[(2,4- dimethylphenyl)imino]methyl] - N - methanimidamide) in cattle dip solutions. Extraction with petroleum ether, followed by IR and gas-liquid chromatography (GLC) gave coefficients of variation of 3.4 and 3.6%, respectively, for 0.010-0.035% amitraz. Dilution of the dip sample with acetone and determination by GLC gave a coefficient of variation of 3.6% in the same range. Recovery of amitraz from fortified dip samples was 97–100%.
Determination of o-Toluenesulfonamide in Artificial Sweeteners Containing Saccharin
Authors: Kacprzak Jurgen L
Published: February 2020

A gas-liquid chromatographic (GLC) procedure with p-toluenesulfonamide (p-TS) as an internal standard is used to determine o-toluenesulfonamide (o-TS), a major impurity in artificial sweetening substances containing saccharin. Although p-TS can itself occur as an impurity in samples, it is usually absent or present in very small amounts; the highest quantity found in the 13 samples analyzed was about 1 ppm. The presence of appreciable amounts, however, would not pose a problem with the GLC procedure. Recoveries of standard o-TS added at various levels were approximately 90%.
Comparison of Methods for Determining Biuret in Urea
Authors: Corominas Luis F , Boy Victor M , Guijosa Manuel
Published: February 2020

The official first action AOAC method for the spectrophotometric determination of biuret in urea, 2.072—2.074, was compared with official first action AOAC method 2.C01-2.C03 (atomic absorption spectrophotometry), 2 simplified versions of 2.072-2.074, and modified versions of 2 alternative procedures of the International Organization for Standardization. Three synthetic urea samples (0.3, 1.4, and 3.0% biuret) and 1 commercial urea sample (1.0% biuret) were analyzed. The methods proved to be equivalent and none showed a definite advantage over 2.072-2.074. The purification of biuret and the interference by ammonia are also discussed.
Nuclear Magnetic Resonance Studies of Cyanogenetic Glycosides: Spectra of Amygdalin and Neoamygdalin in DMSO-d6 and D2O; Epimerization Studies; Predicted Laetrile Spectrum
Authors: Turczan John W , Medwick Thomas
Published: February 2020

The nuclear magnetic resonance (NMR) spectra of amygdalin and neoamygdalin have been studied in D2O and dimethylsulfoxide-d6 and have been compared. The epimerization of amygdalin has been studied under various conditions, using the NMR spectra to monitor changes in the aglycone chiral center. Observations indicate that a base is necessary to abstract a proton from the aglycone and permit epimerization. There is evidence that the surface of the glass container may provide the base (as silicate) because no epimerization is observed when a platinum vessel is used. Epimerization is observed when amygdalin is melted. On the basis of the spectra of prunasin, β3-D-glucose, and β-glucuronic acid, a spectrum has been predicted for Laetrile because the latter compound is not currently available.
Modified Chromogenic α-Amylase Assay for Sprouted Wheat
Authors: Mathewson Paul R , Pomeranz Yeshajahu
Published: February 2020

Sensitivity of a test in which a commercially available substrate was used for the assay of α-amylase in sprouted wheat has been increased by the use of optimally buffered (pH 6.20) Cibacron-Blue dyed amylose at 60°C. With the modified test, measurable α-amylase levels were in the range of 3—30 millidextrinizing units (mDU) as compared to the 10—90 mDU range in a test previously reported for bread wheats. The modification extends the use of the test to evaluation of sprout damage in wheats used in the manufacture of Japanese noodles and sponge cakes.
Reaction-Rate Method for Determining Protein Nitrogen in Grains and Feeds
Authors: Mccracken Michael S , Malmstadt Howard V
Published: February 2020

In a new automated reaction-rate method for the quantitative determination of protein nitrogen in grains and feeds, the ammonia-sodium phenate-hypochlorite reaction is used for the reaction-rate determination. After samples are digested by the official AOAC block digestion procedure, automated instrumentation is used to precisely and rapidly combine the reactants and transfer the mixed solution to an automated spectrophotometer. The rate of formation of the indophenol during 15 sec at 635 nm is automatically determined and compared with rates obtained for nitrogen standards to determine the protein nitrogen content in the sample. Relative standard deviations of about 0.6% are obtained. Results for grain and feed samples are comparable to those obtained by the official AOAC method.
Gas-Liquid Chromatographic and Mass Spectrometric Identification of Chlorinated Trifluorotoluene Residues in Niagara River Fish
Authors: Yurawecz Martin P
Published: February 2020

Several unknown halogenated compounds were detected in Niagara River fish using a method similar to the AOAC multiresidue method for chlorinated pesticides in high-moisture foods. From gas-liquid chromatographic-mass spectrometric (GLC/MS) data and GLC retention times on 3 columns, 7 of the compounds were identified as 4-chloro-α,α,α-trifluorotoluene (0.17—2.0 ppm), 2-chloro-α,α,α-trifluorotoluene (0.002—0.1 ppm), 3,4-dichloro-α,α,α-trifluorotoluene (0.02—0.28 ppm), 2,4-dichloro-α,α,α-trifluorotoluene (0.02—0.17 ppm), 2,3-dichloroa, α,α,α-trifluorotoluene (trace-0.005 ppm), 2,6-dichlorotoluene (not quantitated), and 2,4,5-trichlorotoluene (0.31 ppm was found in the only sample quantitated). Other isomers of triand tetrachloro-α,α,α-trifluorotoluene and di-, tri-, and tetrachlorotoluene were also present in these samples. Recoveries of the specific chlorinated trifluorotoluenes identified in these samples ranged from 86 to 108%.
Automated Sampling/Readout Devices for Analysis of Dissolution Media: Continuous-Cycling System and Application to Dissolution Profiling of Phenytoin Products
Authors: Myrick James W , Wells Clyde E
Published: February 2020

An automated system has been developed for sampling and analyzing dissolution media for in vitro determinations. This system simultaneously takes filtered aliquots at precisely spaced intervals from 6 test vessels, dilutes each aliquot, and presents them sequentially either for direct absorbance monitoring or for additional chemical treatment before absorbance monitoring. Because the apparatus dilutes the aliquots by a factor of 1:6, the system is most effective in monitoring unit dosage levels of 50—500 mg. Lower dosages may be examined if an extremely sensitive detection method is available. Long-term operation of the sampler on a 10 min cycle basis showed a coefficient of variation of 0.46%. The sampling system was used with a newly developed, sensitive automated method for determining phenytoin and sodium phenytoin. The sample is treated at pH 8.1 with a mercuric chloride solution to form a phenytoin/mercury complex which is extracted into chloroform. Adding dithizone to the chloroform extract produces the typical orange mercuric dithizonate with peak absorbance at 480 nm. Detection sensitivity is 0.28 μg phenytoin/ml, corresponding to 5% dissolution of a 30 mg tablet in 900 ml medium. The sampler and detection system showed a coefficient of variation of 0.95% on a 15 min cycle basis. Phenobarbital interferes with the method.
Spectrophotometric Analysis of Binary Mixtures of Sulfonamides
Authors: Wahbi Abdel-Aziz , Abdine Hassan , Korany Mohamed , El-Yazbi Fawzi
Published: February 2020

Different methods for analyzing binary mixtures by using 2 wavelengths are reviewed. The absorbance ratio calculated at 2 wavelengths, not including the isoabsorptive point, was a quadratic function of relative concentration. The curve-fitting process using orthogonal polynomials was applied to obtain the quadratic equation. An absorbance ratio can be used as a rapid purity index for sulfacetamide sodium in the presence of sulfanilamide. Sulfacetamide sodium has been determined in eye drop preparations.
Preparation of Pure 1- and 2-Naphthalenesulfonic Acids and Analysis of Their Mixtures
Authors: Marmion Daniel M
Published: February 2020

Procedures are presented for the preparation of the pure sodium salts of 1- and 2-naphthalenesulfonic acids, and for the high pressure liquid chromatographic (HPLC) analysis of mixtures of both in the presence of highersulfonated homologs. The purified samples are prepared by the recrystallization from water of commercially available materials. The HPLC procedure specifies a 4.6 mm id × 25 cm Whatman Partisil PXS10/25 ODS-2 column, an eluant prepared by diluting 90 ml isopropanol to 2 L with 0.15M aqueous (NH4)2S04, and isocratic elution at 40°C.
Gas-Liquid Chromatographic Determination of Individual Sugars in Confectionery Products
Authors: Prager Manfred J , Miskiewicz Michael A
Published: February 2020

A gas-liquid chromatographic (GLC) procedure is presented for the separation and quantitative determination of sucrose, lactose, maltose, and glucose in commercial confectionery products. By converting reducing sugars to oximes and then forming trimethylsilyl ethers of these compounds and separating them on a 6 ft × 4 mm id glass column packed with 2% OV-17 on 100—120 mesh Supelcoport, single peaks were obtained for each of the sugars. Results for sugars present in samples at levels of 5% or more are within 2.8%, on the average, of results obtained by polarization measurements. The data also compare favorably with others in the literature on similar products analyzed by other GLC procedures that do not involve oxime formation.
Screening Test for Amygdalin in Tablets, Solutions, Powders, and Seeds
Authors: Egli Keith L
Published: February 2020

A rapid screening test for detecting amygdalin in tablets, solutions, powders, and seeds, based on the liberation of both hydrogen cyanide and benzaldehyde as a result of enzymatic decomposition, is described. The procedure can be easily performed outside the laboratory with small amounts of sample; the samples require no special preparation or pretreatment. The test can be performed in ≤60 min and is sensitive to at least 0.2 nig amygdalin. Vicianin, lucumin, prunasin, and sambunigrin would also give positive tests, but instrumental analysis can be used to distinguish amygdalin from these compounds.
Determination of Microquantities of Lead in Ferrous Sulfate, Zinc Oxide, Manganese Sulfate, and Iron Powder by Using Solvent Extraction and Flameless Atomic Absorption Spectroscopy
Authors: Ng Samuel S M , Bhattacharyya Pranab K
Published: February 2020

A method is described for quantitative measurement of lead at < 1 ppm levels in ferrous sulfate, zinc oxide, manganese sulfate, and iron powder by using solvent extraction and flameless atomic absorption spectroscopy. Lead is separated from the heavy matrix before the analysis. It is complexed with sodium diethyldithiocarbamate in the presence of excess sodium cyanide and ammonium citrate and extracted into methyl isobutyl ketone. The extract is placed in a graphite furnace for quantitation. The sensitivity and absolute sensitivity of this method are 0.01 μg/mL and 5.0 X 10-11 g lead, respectively. The recovery of lead from the spiked samples was good. The reproducibility of the signal response for sample solutions containing ≥ 0.2 ppm lead is within 6.0%.
Gas-Liquid Chromatographic Determination of Limonene in Orange Juice
Authors: Lund Eric D , Shaw Philip E
Published: February 2020

The limonene content of orange juice was quantitatively determined by a porous polymer trapping gas-liquid chromatographic (GLC) procedure. A 10 mL juice sample was stripped of volatiles by a nitrogen stream, and the limonene and other volatiles were trapped on Chromosorb 105. The volatiles were desorbed and collected in the upstream end of a GLC column. The column was rapidly heated, and the area of the resultant sharp limonene peak was measured. Recoveries ranged from 96 to 103% over the usual concentration range of limonene in orange juice (0.006–0.120 volume % ) . Coefficients of variation for repeated measurements (precision) were ±1 % , and for overall accuracy, ±3 % . Experimental error increased considerably in the 0.001-0.003% range. These errors are comparable to those reported for the presently used Scott-Veldhuis bromate titration procedure. Analysis of a canned orange juice sample showed that the titration method gave a slightly higher limonene value, probably due to consumption of bromine by a small amount of non-limonene volatiles.
Sampling of Insecticides from Pressurized Cans: Collaborative Study
Authors: Kawano Yoshihiko
Published: February 2020

Seven laboratories collaboratively studied 3 methods for sampling water-based insecticides in pressurized cans. Method 1 was a direct sampling method where the sample was collected continuously from an aerosol outlet into the solvent, using a U-shaped sampling assembly. Method 2 was an indirect method, in which the sample was collected in the solvent from an open can after the propellent was discharged under frozen conditions. Method 3 was an extension of Method 1, where ≥3 samples were collected continuously from an aerosol outlet into the solvent through a U-shaped sampling assembly. The solvent, which contained the active ingredient, was concentrated and transferred to a suitable volumetric flask for gasliquid chromatographic (GLC) analysis. The means of the analytical results for Methods 1 and 3 did not show a significant difference at the 95% confidence level. However, a significant difference was found at the 95% confidence level for the mean value for Method 2 compared with the means for Methods 1 and 3. Methods 1 and 3 have been adopted as official first action for sampling pressurized cans containing aerosols.
Methods for Determining Carbohydrates, Hydroxymethylfurfural, and Proline in Honey: Collaborative Study
Authors: White Jonathan W
Published: February 2020

A modification of the official selective absorption method for honey carbohydrates, 31.124–31.133, was studied collaboratively; the determinations of sucrose, total monosaccharides, disaccharides, and higher sugars by this procedure were satisfactory and were adopted by the AOAC. High pressure liquid chromatography of glucose, fructose, and sucrose in honey showed better precision than the modified official method and gave concordant results; it was also adopted. Two methods for hydroxymethylfurfural do not qualify. A method for proline was also adopted.
Spectrophotometric Determination of Tolbutamide in Tablets
Authors: Elsayed M Abdel-Hady , Belal Saied F , Elwalily Abdel-Fattah M , Abdine Hassan
Published: February 2020

Two spectrophotometric methods, Glenn's method of orthogonal function and the basic dye method, are described for determining tolbutamide in tablets without interference from the tablet excipients. In Glenn's method, the absorbance of tolbutamide in 95% ethanol is measured in the vicinity of 250–270 nm at 4 nm intervals and the p2 coefficient is calculated. The coefficient is linearly related to concentration within a range of 0.1–0.4 mg/mL. Tolbutamide gives a complex of a ratio 1:1 with basic dye Brilliant Cresyl Blue (BCB) or Safranin T (ST). The complex is easily extracted with chloroform. The absorbance of the chloroform extract is measured against either a blank or reference experiment. The latter is obtained by using a specific concentration of tolbutamide: 0.4 mg/mL in tolbutamide–BCB or 0.024 mg/mL in tolbutamide-ST. The ST complex method is more sensitive compared with the other methods. When the t-test is applied, the results of the proposed methods are more accurate than those of the traditional ultraviolet spectrophotometric method.
Spectrophotometric Determination of Acetaminophen in Tablets, Sirups, and Suppositories
Authors: Elsayed M Abdel-Hady , Belal Saied F , Abdel-Fattah M Elwalily , Abdine Hassan
Published: February 2020

A differential spectrophotometric method and Glenn’s method of orthogonal function are described for the assay of acetaminophen in tablets, sirups, and suppositories. Interference from excipients in the formulations is thereby avoided. Accuracy of the analyses is greater with the proposed methods than with the British Pharmacopoeia method.
Gas-Liquid Chromatographic Quantitation of Pheneyclidine.HCl in Powders: Collaborative Study
Authors: Clark Charles C
Published: February 2020

Six laboratories collaboratively studied a method for the quantitative gas-liquid chromatographic (GLC) determination of pheneyclidine. HCl in powders. The pheneyclidine.HCl and other water-soluble compounds are dissolved in dilute HC1. A portion of the aqueous solution is made weakly basic with K2HPO4, and the organic-soluble compounds are extracted in CHCI3 for the GLC determination of the pheneyclidine.HCl. Eicosane (n-C20) is incorporated in the extracting CHC13 as an internal standard. The samples collaboratively studied included samples of known pheneyclidine. HCl concentration and one sample of unknown purity. Recoveries ranged from 92.1 to 104% and per cent standard deviations from 1.05 to 3.39. The method was adopted as official first action.
Thin Layer Chromatographic Determination of Aflatoxins, Ochratoxins, Sterigmatocystin, Zearalenone, Citrinin, T-2 Toxin, Diacetoxyscirpenol, Penicillic Acid, Patulin, and Penitrem A
Authors: Gimeno Alberto
Published: February 2020

A general method is described for determining 16 mycotoxins in mixed feeds and other food products used in the manufacture of these feedstuffs. The mycotoxins are extracted and cleaned up by extracting with solvents of different pH. Thin layer chromatography is used to separate the toxins; toxins are then quantitated by the limit detection method. The minimum detectable concentration of mycotoxins in various products is: aflatoxin B1 or G1, 4–5 μg/kg; cchratoxin A or ethyl ester A 140–145 μg/kg; citrinin 600–750 μg/kg; zearalenone, 410–500 μg/kg; sterigmatocystin, 140–145 μg/kg; diacetoxyscirpenol, 2400–2600 μg/kg; T-2 toxin, 800-950 μg/kg; patulin, 750-800 μg/kg; penitrem A 14,000–14,500 μg/kg; penicillic acid 3400-3650 μg/kg.
Mineral Oil Extraction of Light Filth from Rubbed Sage Collaborative Study
Authors: Colliflower Emma J , Thrasher Joel J
Published: February 2020

The official methods for extracting light filth from rubbed sage, 44.D08–44.D10, specifies a hot isopropanol pretreatment and flotation from cooled dilute isopropanol with mineral oil to extract light filth. The method gives good recoveries, but occasionally excessive interfering plant material is extracted along with the filth elements. A new method has been developed in which chloroform is used for pretreatment instead of isopropanol, and Tween 80-EDTA is added twice rather than once. This method has given consistently cleaner filter papers and better recoveries for rodent hairs, 85 vs. 79%, and for elytral squares, 95 vs. 84%. The new method has been adopted as official first action.
Extraction of Light Filth from Canned Green Leafy Vegetables: Collaborative Study
Authors: Dent Russell G , Boese Jack L
Published: February 2020

The official first action method, 44.108, for the extraction of light filth from whole or chopped canned greens specifies a waterheptane flotation that results in the flotation of an excessive amount of interfering plant material and in low recoveries. A new method has been developed using a 40% isopropanol-watermineral oil flotation. The new method yielded a decreased amount of plant material and 84.9% recovery of the aphid spike compared with 42.5% recovery of the spike by the official method. The new method has been adopted as official first action to replace the existing method, except for broccoli.
New Brine Saturation Technique for the Extraction of Light Filth from Rubbed Sage, Paprika, and Corn Meal: Intralaboratory Study
Authors: Freeman Clarence C
Published: February 2020

A new and widely applicable technique for the isolation of light filth from foods has been developed. It includes a simple alcohol defatting followed by a brine saturation of the product by heating and cooling and a subsequent trapping of the filth elements with olive oil and tap water. The methods circumvent the use of hazardous and expensive solvents and lengthy defatting and/or pre-treatment procedures. In an intralaboratory study, recoveries of elytral squares and rodent hair fragments added to paprika, rubbed sage, and corn meal ranged from 95.8 to 100%.
Gas-Liquid Chromatographic Determination of Monosodium Glutamate in Soups and Soup Bases
Authors: Conacher Henry B S , Iyengar Jagannath R , Miles Walter F , Botting Herbert G
Published: February 2020

A method is given for determining monosodium glutamate (MSG) in soups and soup bases by gas-liquid chromatography (GLC) of the trimethylsilyl ether derivative of glutamic acid. This method compared favorably with existing methods including GLC of the trifluoroacetate (TFA) /butyl ester derivative, and analysis on an amino acid analyzer. In addition, some samples were analyzed by GLC/mass spectrometry. The MSG content of various products ranged from approximately 0.2% in some condensed soups to 13.1% in bouillon cubes. The method, which can detect as little as 0.05%, requires only a 10 min single step derivatization at room temperature and is preferred to the TFA/butyl ester technique.
High Pressure Liquid Chromatographic Determination of Vitamins A and E in Cereal Products
Authors: Widicus Warren A , Kirk James R
Published: February 2020

A rapid method for the simultaneous determination of vitamins A and E in fortified cereal products has been developed. Saponification of retinyl or tocopheryl esters is not required, permitting direct injection of the extracted lipids onto the high pressure liquid chromatographic column without sample cleanup. Elution times of 2.46 and 3.40 min were determined for retinyl palmitate and tocopheryl acetate, respectively, using a μPorasil column and an isocratic mobile phase of hexane-chloroform (85+15) with a flow rate of 1.5 mL/min. The average recovery of retinyl palmitate was 99.2% (std dev. 4.28), and the average recovery of tocopheryl acetate was 94.9% (std dev. 4.10) in 2 cereals containing corn, oat, rice, and wheat. No significant amounts of naturally occurring tocopherols were found in the cereals.
Automated Fluorometric Determination of Thiamine and Riboflavin in Infant Formulas
Authors: Dunbar Walter E , Stevenson Kenneth E
Published: February 2020

Commercial infant formulas were analyzed simultaneously for thiamine and riboflavin by an automated fluorometric method and by the AOAC manual fluorometric methods. For 10 products, the mean thiamine and riboflavin results determined using the automated method ranged from 104 to 113% and 90 to 112%, respectively, of those by the AOAC manual methods. The coefficients of variation for thiamine and riboflavin ranged from 1.05 to 3.90% and 0.60 to 2.48%, respectively, for the automated method, and 1.48 to 3.86% and 0.69 to 10.9%, respectively, for the manual methods. Using the automated method, mean recoveries of thiamine and riboflavin added to samples were 103 and 104%, respectively. The automated method used a common sample preparation to determine both thiamine and riboflavin, and gave results equivalent to, or better than, those obtained by the manual methods.
Pyridine Extraction Method for Determination of Bacitracin in Feeds: Collaborative Evaluation
Authors: Ragheb Hussein S
Published: February 2020

Seventeen laboratories evaluated the pyridine extraction method and neomycin-sensitized agar for the determination of zinc and MD bacitracin in swine and broiler rations at 10 and 100 g/ton. The method was also applied to the analysis of 2 premixes labeled 50 g/lb (MD bacitracin) and 40 g/lb (zinc bacitracin). Bacitracin activity was determined on each of 2 days with 2 dilutions on each day. No significant difference was found between dilutions within a day or between days for each sample. The type of bacitracin or type of feed did not significantly affect results. The difference in results between MD and zinc bacitracin in premixes approached significance. The large coefficients of variation for premixes (ca 13%) and complete feeds (ca 15–30%) indicate operational problems. The main difficulty was evaporation of pyridine. Some laboratories were not able to evaporate it completely, whereas others lost bacitracin activity, probably due to high temperature of drying. The pyridine extraction method as in 42.200 and 42.204 should be discontinued.
Determination of Chlorinated Pesticide Residues in Foods. II. Potassium Permanganate Oxidation for Cleanup of Some Vegetable Extracts
Authors: Suzuki Takashi , Ishikawa Kiyoshi , Sato Nobutoshi , Sakai Kei-Ichi
Published: February 2020

A potassium permanganate-dilute sulfuric acid KMnO4/dilute H2SO4 oxidation procedure was developed to supplement Florisil cleanup of some vegetable extracts. Following sample preparation and Florisil cleanup, a reaction mixture of the n-hexane eluate from the Florisil cleanup, 4% KMnO4, and 40% H2SO4 (l+l+l) was shaken in a test tube 2 min at room temperature and then centrifuged. The n-hexane phase was washed with 2 mL 0.1N NaOH and analyzed by GLC. Twelve chlorinated pesticides were completely recovered in the n-hexane phase. Aldrin was not recovered because its extreme instability caused it to decompose even in neutral solutions. Chlorinated pesticide residues in onion, garlic, carrot, and radish root were easily analyzed by the application of this oxidation procedure.
Evaluation of Two-Way Riffles for Precise Division of Blended Fertilizers
Authors: Woodis Terry C , Holmes John H , Hunter G Bradley , Johnson Frank J
Published: February 2020

Evaluation of two-way riffles showed that gated riffles are superior to open-chute riffles. The proper technique appears to play a significant role in subdivision of blended fertilizers with the open-chute riffle, while the use of the gated riffle virtually eliminates error due to technique. A blended fertilizer prepared from materials having disparate particle sizes can be divided with a gated riffle to give a subsample that is representative of the original lot.
High Pressure Liquid Chromatography of Ester and Salt Formulations of 2-Methyl-4-Chlorophenoxyacetic Acid
Authors: Stevens Timothy , Grorud Robert B
Published: February 2020

A high pressure liquid chromatographic (HPLC) assay of amine salt and ester formulations of MCPA has been collaboratively studied. The AOAC 2,4-D HPLC method has been modified for application to MCPA products. The MCPA methodology is identical to that of 2,4-D except in strength of mobile solvent, pH of mobile solvent, heating of ester formulations to 50°C to ensure complete saponification, and the use of glass microfiber filters. The method is specific and separates all known impurities. Examination of chromatograms and percentage results from 8 collaborators indicate that selection of a practical internal standard would improve precision in the procedure and a second collaborative study is recommended.
Preparation and Spectral Analysis of 3,3',4,4'-Tetrachloroazobenzene and the Corresponding Azoxy and Hydrazo Analogs
Authors: Hsia M T Stephen , Burant Charles F
Published: February 2020

An efficient preparation was developed for 3,3',4,4'-tetrachloroazobenzene and the corresponding azoxy and hydrazo derivatives, based on the lithium aluminum hydride reduction of 3,4-dichIoronitrobenzene. Batches were analyzed for purity by using a reverse phase high pressure liquid chromatographic method. All 3 compounds can be synthesized in gram quantities with 97–99% purity. Detailed mass, infrared, and nuclear magnetic resonance spectral analyses are presented.
Gas-Liquid Chromatographic Determination of Thiabendazole and Methyl 2-Benzimidazole Carbamate in Fruits and Crops
Authors: Tjan Gwan H , Jansen John T A
Published: February 2020

A method is described for the electron capture gas-liquid chromatographic determination of thiabendazole and methyl 2-benzimidazole carbamate (MBC) after derivatization with pentafluorobenzyl bromide (PFB-Br). The samples are extracted with ethyl acetate, and the residual thiabendazole, benomyl, and MBC are isolated by liquid-liquid extraction into dilute HC1. After neutralization and re-extraction with ethyl acetate, thiabendazole and MBC are reacted with PFB-Br to form the PFB derivatives. Alumina column chromatography was used to clean up extracts, and the derivatives could be detected as low as 5–10 pg. Recoveries were 95-98% from fruits fortified with 0.3-2.0 ppm thiabendazole; recoveries were 91–97% when 0.05–1.0 ppm benomyl/MBC were added to fruits/crops. The PFB derivatives were identified by gas-liquid chromatography-mass spectrometry.
Rapid Methods for Differentiating Reactivated from Residual Phosphatase in Milk and Cream: Collaborative Study
Authors: Murthy Gopala K , Peeler James T
Published: February 2020

Three methods for differentiating reactivated from residual phosphatase in milk and cream were collaboratively tested using both magnesium acetate and magnesium chloride for reactivating phosphatase. The methods evaluated were the modified Scharer rapid test, the rapid colorimetric test, and the Rutgers method. Nine collaborators tested 6 unknown milk samples containing reactivated and/or residual phosphatase, and 16 collaborators tested 6 unknown cream samples containing reactivated and/or residual phosphatase. Results indicated that use of magnesium acetate in place of magnesium chloride for reactivating phosphatase improved test results. Visual tests (modified Scharer rapid and Rutgers) predicted correct results when the samples contained high levels of reactivated or residual phosphatase. In borderline cases where the reactivated phosphatase contents of the undiluted control sample and the diluted sample containing Mg were very close, the test results of the visual methods were significantly different from 100% correct results at the α = 0.05 level. Use of a photoelectric colorimeter or its equivalent for measuring the absorbance in conjunction with the modified Scharer rapid test improved results considerably. The modified Scharer rapid test was adopted official first action.
Modified Karl Fischer and Vacuum Oven Moisture Methods for Cheese Products: Comparative Study
Authors: Christen Genevieve L , Richardson Gary H
Published: February 2020

In a modified Karl Fischer method, methanolchloroform (1+1) was used to extract moisture from cheese after homogenization in an automatic titrimeter. The mean coefficient of variance was high (0.82%) for the modified apparatus as determined by the values obtained during computation of the Karl Fischer factor. Variance from other sources in the assay was not significant. Comparative data on 6 different cheese samples produced within-day coefficient of variance values from 0.46 to 0.85%, following discard of outlying data, compared to 0.12 to 0.30% for within-day values obtained using the official vacuum oven method. A sample could be assayed in 7 min. The apparatus costs less than equipment required for some rapid methods; however, solvent and reagent costs, high coefficient of variance values, and the need for expensive reagents suggest that this approach is impractical for extracting moisture from cheese products.
Interlaboratory Comparison of Behavioral Testing
Authors: Butcher Richard E , Hoar Richard M , Nolan Granville A , Vorhees Charles V
Published: February 2020

New requirements by several regulatory agencies for testing the psychotoxic potential of new drugs, chemicals, and environmental contaminants raise unique problems. In order to assess intra- and interlaboratory reliability of behavioral tests a model animal maze learning procedure was designed and run in 3 cooperating laboratories. Uniform procedures were written and identical mazes were constructed. Normal control animals of identical age and sex, but of different strains, were used by the participants. A positive control group of neurologically impaired rats was run by one laboratory. Significant differences in test results among the laboratories were found. Data obtained from the positive control animals (X− errors = 28.3) indicated a learning impairment statistically significant compared to the negative control data (X− errors = 12.7) from any of the participating laboratories. Based on the results of this study, a reasonable standard of interlaboratory reliability in behavioral testing appears an attainable goal.
Collaborative Studies on the Salmonella/Microsome Mutagenicity Assay
Authors: Dunkel Virginia C
Published: February 2020

Although the Salmonella/plate test has been used extensively, a collaborative study was undertaken to determine the interlaboratory reproducibility of this microbial mutagenicity assay. Four laboratories participating in the study have completed testing, under code, of 61 carcinogens and noncarcinogens. All chemicals were tested both with and without metabolic activation in Salmonella typhimurium strains TA1535, 1537, 1538, 98, and 100. The metabolic activation systems used were derived from the livers of both uninduced and Aroclor 1254-induced Fischer rats, B6C3F1 mice, and Syrian hamsters. Analysis of the results on 23 of the chemicals tested in 3 of the participating laboratories showed that 8 were negative when tested in all laboratories and 13 were positive. Two chemicals gave positive results in 2 laboratories; the same 2 chemicals were negative when tested in the third laboratory.
Overview and Status of in vitro Transformation
Authors: Sivak Andrew
Published: February 2020

The development of standardized assay procedures has permitted the exploitation of cell culture systems as bioassay tools for the detection of chemical carcinogens. These systems fall generally into 3 classes: diploid cell strains, Syrian hamster embryo cells; cell lines, mouse BALB/c-3T3 and mouse C3H-10½; and cells + virus, Fischer rat cells infected with Rauscher leukemia virus and Syrian hamster embryo cells infected with adenovirus. The results accumu-lated to date show a good correlation between transformation response in cell culture and carcinogenicity of chemicals in whole animal studies. The major advantages of these systems are their relative brevity (10 days–6 weeks) and resultant low costs, their agreement with whole animal bioassays, and their direct biological relevance to the carcinogenic process. The present major disadvantages are the uncertain nature of the metabolic capabilities of the target cells and the lack of a metabolic activation system that is reliable and adaptable for routine bioassays. The development of epithelial cell systems such as breast, liver, lung, and skin may solve the problem of carcinogen metabolism as well as provide target cells that are representative of major organ sites for cancer in man. The rational use of cell culture bioassays for neoplastic transformation is a valuable component of the toxicological armamentarium to assess risk to humans from exposure to chemicals.
Gas-Liquid Chromatographic Determination of Adipic Acid in Crackling Candy and Soft Drinks
Authors: Ito Yoshio , Ogawa Shunjiro , Iwaida Masahiro
Published: February 2020

A procedure was developed for the simple and rapid determination of adipic acid in crackling candy and also in soft drinks. An alkaline solution of sample was extracted with ethyl ether to remove fatty substances, and H2SO4 was added to water layer to adjust the pH to <2. The acidified layer was saturated with NaCl and then extracted with ether. After drying, the ether layer was concentrated and the adipic acid in the concentrate was methylated using the diazomethane method. An aliquot of the methylated solution was injected into a gas chromatograph equipped with a flame ionization detector. Recovery of adipic acid from crackling candy and from 2 kinds of soft drinks that had been fortified at the 200 ppm level was over 96 %. An interlaboratory test was carried out on the determination of adipic acid in orange soft drink. The results obtained by 6 laboratories were between 91 and 100% compared with the theoretical value.
Instrumental Evaluation of Readily Carbonizable Substances in Citric Acid
Authors: Dokladalova Jarmila , Upton Ronald P
Published: February 2020

A procedure has been developed for objective evaluation of the color generated in the USP test by readily carbonizable substances in citric acid. A tristimulus instrument–Hunterlab Color Difference Meter Model D25D3P–is used. The total color and yellowness defined by the aid of APHA (American Public Health Association) color standards can be measured with a precision better than ±2.5% relative (95% confidence interval). The procedure has been used successfully in our quality control laboratories for over 2 years, and the color determined in more than 1400 samples has been in agreement with the visual evaluation as required by USP.