bluuebunny/crossref_metadata_2025 huggingface dataset:
Chlorinated Compounds and Phenols in Tissue, Fat, and Blood from Rats Fed Industrial Waste Site Soil Extract: Methods and Analysis
Authors: Stein Vincent B , Rajinder Singh Narang
Published: February 2020

A method was developed to analyze rat tissue, fat, and blood for some of the chlorinated compounds found in an extract of soil from an industrial waste site. Extraction with hexane and then with ethyl ether–hexane (1 + 1) was followed by concentration over steam, and gas chromatographic analysis with an electron capture detector. Volatile compounds were analyzed in a glass column coated with 6% SP-2100 plus 4% OV-11 on Chromosorb W. Semivolatile compounds, chlorinated compounds, and pesticides were analyzed in a 70 m glass capillary column coated with 5% OV-101. Phenols were analyzed in a glass column packed with 1% SP-1240 DA on Supelcoport. However, the most efficient means of separation was to use the same glass column for volatile compounds, a DB-5 fused silica capillary column for semivolatile compounds, pesticides, and phenols, and the same 1 % SP-1240 DA glass column for separation of (J-BHC and pentachlorophenol. Recoveries ranged from 86.3 ± 9.1% (mean ± standard deviation) to 105 ± 10.4%. Sensitivities for semivolatile chlorinated compounds, pesticides, and phenols were about 4 ng/g for fat, 1 ng/g for tissue, and 0.2 ng/mL for blood. Sensitivities for volatile compounds were about 4-fold higher (16, 4, and 0.8, respectively). Sensitivities for dichlorobenzenes and dichlorotoluenes were 8 ng/g for fat, 2 ng/g for tissue, and 0.4 ng/mL for blood.
Simple Spectrophotometric Method for Determination of Phosphine Residues in Wheat1
Authors: Rangaswamy J R
Published: February 2020

A method has been developed for determination of phosphine residues in wheat, based on the reaction of phosphine with silver nitrate in aqueous solution to form an egg-yellow chromophore with an absorption maximum at 400 nm. At this wavelength, there is a linear relationship between absorbance and concentration of phosphine in the range 10–100 ng/mL. Phosphine-fumigated wheat is soaked in a known volume of AgNO3 solution, and the absorbance of the filtrate is read against a blank at 400 nm. The method is sensitive, with lower detection and estimation limits of 0.008 and 0.01 μg PH3, respectively. Recovery of added phosphine from a closed system was 85–100%. Accuracy for this method has been compared with that for the gas chromatographic method.
Extraction of Pesticides from Environmental Samples by Steam Distillation
Authors: Nash Ralph G
Published: February 2020

Steam distillation was used to extract several pesticides from samples of soil, plant tissue, and air (by using polyurethane foam filters). The major advantages of steam distillation over most other procedures are the small amounts of organic solvent required (10 mL) and the elimination of extract cleanup. In addition, the procedure is reasonably rapid and requires no special laboratory glassware. Recoveries of 22 pesticides from fortified samples were >75%, except for toxaphene and methoxychlor; recoveries were greater for the more volatile pesticides. Steam distillation extraction recoveries of chlorinated hydrocarbon insecticides from weathered (33 years) soil samples, compared with exhaustive Soxhlet extraction, were similar, except for DDT residues which depended on soil type. DDT residue extraction from a muck by distillation was poor (only 21–60% compared with Soxhlet extraction). The procedure is apparently limited to fairly nonpolar pesticides that are stable in steam or heat.
Thin Layer Chromatographic Determination of Deoxynivalenol in Wheat and Corn
Authors: Trucksess Mary W , Nesheim Stanley , Eppley Robert M
Published: February 2020

A thin layer chromatographic (TLC) method for determining deoxynivalenol (DON) in corn and wheat was developed. DON is extracted from the grain with acetonitrile–water (84 + 16) and filtered through a column of mixed alumina–charcoal–Celite (0.5 g + 0.7 g + 0.3 g). The solvent is evaporated on a steam bath. Ethyl acetate is added to the residue and heated to dissolve DON. After cooling, the residue is transferred to a vial with additional ethyl acetate and is dissolved in CHCl3–acetonitrile (4 + 1) for TLC on an AlCl3-impregnated silica gel plate with CHCI3–acetone–isopropanol (8 + 1 + 1). The plate is heated in a 120°C oven for 7 min; a blue fluorescent spot is produced under longwave ultraviolet light. DON is quantitated visually and/or fluorodensitometrically by comparison with reference standards. The minimum detectable amount of DON is ca 20 ng/spot. The limit of DON determination is ca 40 ng/g for wheat and 100 ng/g for corn. Recoveries of DON added to wheat and corn at 100, 500, and 1000 ng/ g levels were 85, 93, and 88% and 77, 80, and 80%, respectively.
Determination of Aflatoxin Mt in Milk by Liquid Chromatography with Fluorescence Detection
Authors: Cohen Huguette , Lapointe Michel , Marc Fremy Jean
Published: February 2020

A liquid chromatographic (LC) method is proposed for the determination of aflatoxin Mi in milk. The method was successfully applied to both liquid whole and skim milk and also whole and skim milk powder. The samples are initially extracted with acetonitrile–water followed by purification using a silica gel cartridge and a C18 cartridge. Final analysis by LC was achieved using a radial compression module equipped with a 5 μm C18 column and a fluorescence detector. The method was successfully applied to samples at levels of 10 to 0.08 ppb added aflatoxin Mi with recoveries in the range of 70–98%.
Performance of Methods of Analysis Used for Regulatory Purposes. I. Drug Dosage Forms. A. Chromatographic Separation/Spectrophotometric Measurement
Authors: Horwitz William , Albert Richard
Published: February 2020

The precision attributes of one of the most widely used methods for the assay of drug dosage forms, partition chromatographic separation on diatomaceous silica and spectrophotometric measurement (ultraviolet, risible, or fluorometric), were recalculated on a consistent statistical basis, using a computer program FDACHEMIST. Eighteen collaborative studies of methods approved by AOAC during the past 10 years, of 24 compounds involving 69 dosage forms (here designated as materials), conducted by an average of 10 laboratories each, were reviewed.

The original data with no outliers removed were used for the calculation of mean, median, and standard deviations and coefficients of variation, both within- (CVº) and between-laboratory (CVx), for each material. Outliers in each data set were flagged by the Dixon and Grubbs tests for extreme values, the Cochran test for excessive variance within a laboratory, and the Youden rank sum test for consistent systematic deviations by specific laboratories.

The change in CVs if outliers are removed is tabulated and evaluated, generally using a 20% or greater outlier removal rate as excessive. That CVx is chosen for each material which, with a minimum rejection of outliers (frequently zero), is acceptable in the light of the purpose of the assay and historical values. The method is approximately characterized by a CVx of 2.25% and CVº of 1.25% (CVº/CVx ratio of 0.56), with an average outlier rejection rate of 2.5% of the reported values. The precision parameters from the analyses of 80% of the materials studied could be accepted as is (without flagged outliers removed), although data from analyses of 48 % of the materials included contained outliers at the 95% or higher confidence level (single tail test).

The CVs appear to be independent of the chemical nature of the analyte (phenylalkanolamines, thiazides, steroids, alkaloids, and miscellaneous) or the nature of the matrix (tablets, capsules, solutions). The CVx to some degree depends on concentration with most of the values for CVx falling within the following crude prediction limits (95% confidence level) for each indicated analyte level: 100% concentration, 0-2.5%; 10%, 0.5-3.0; 1%, 1.0-3.5; 0.1%, 1.5-4.0; and 0.01%, 2.0- 4.25. Systematic deviations were not significant for this method, since means from the analyses of synthetic formulations were usually within 98-102% of the target value.
Liquid Chromatographic Determination of Hydrocortisone in Bulk Drug Substance and Tablets: Collaborative Study
Authors: Walters Milda J ,   Collaborators:, Falcone N , Hanel K G , Jefferson E H , Moyer L L , Scott E P , Tsuru K
Published: February 2020

A normal phase liquid chromatographic (LC) method for determining the hydrocortisone content of bulk drug substance, tablet composites, and individual tablets was subjected to a collaborative study by 6 laboratories. The results showed a mean recovery of 98.5% for an authentic tablet formulation and reproducibility coefficients of variation of 0.97, 1.6, and 2.7% for bulk drug substance, tablet composites, and individual tablets, respectively. Infrared (IR) and thin layer chromatographic (TLC) identification tests, also included in the collaborative study, were satisfactory. The LC method for determining hydrocortisone in bulk drug substance, tablet composites, and individual tablets, with IR and TLC identification, has been adopted official first action.
Separation and Identification of Nine Penicillins by Reverse Phase Liquid Chromatography
Authors: Briguglio Gregory T ,   Collaborators:, Lau-Cam Cesar A
Published: February 2020

A simple and rapid high performance liquid chromatographic method was developed for the separation and identification of amoxicillin, ampicillin, cloxacillin, dicloxacillin, methicillin, oxacillin, nafcillin, penicillin G potassium, and penicillin V potassium. The antibiotics were separated at ambient temperature on a Chromegabond 10 μm Cis column with acetonitrile-methanol-O.OlM potassium dihydrogen phosphate buffer, pH 4.7 (19 + 11 + 70), at 1 mL/min. A variable wavelength detector set at 225 nm, 0.16 AUFS, and a recorder set at 0.25 cm/min were used for the detection. Individual antibiotics and their mixtures were dissolved in the mobile phase and injected into the chromatograph through a 20 μL injection loop. Baseline separation was observed for virtually all 9 antibiotics. The entire mixture was resolved in less than 30 min. The method was sensitive, reproducible, and applicable to the qualitative analysis of commercial dosage forms.
Karl Fischer Determination of Water in Oils and Fats: International Collaborative Study
Authors: Bernetti Raffaele , Kochan Stephanie J , Pienkowski James J ,   Collaborators:, Hendrikse P W , Holme R A , Kielbaskiski R , Lin S W , Manning R G , Olah I , Pike M , Pocklington W D , Prins W F , Priss A , Somkaite R , Steele W M , Trautschold E W , Wijsman J A , Wolff P
Published: February 2020

Four samples of soybean oil refining process—a crude oil, a refined oil, an acid oil, and a deodorizer distillate—representing water contents from 0.02 to 3% were submitted to 16 laboratories for analysis by the Karl Fischer method ISO/TC 34/SC11/N99 recommended by the International Organization for Standardization. The laboratories were asked to perform 2 sets of replicate analyses within 2 weeks. Data population was homogeneous at the 95% confidence level except for the acid oil sample where a sampling problem caused wider than expected variation between laboratories. However, overall results indicated interlaboratory variations of the order of 15% at the 0.3% moisture level, in line with the 10% coefficient of variation suggested by the American Oil Chemists' Society at the 0.5% level. The experience of several participants in practicing the method leads to the recommendation that the draft method be modified to include special care in handling heterogeneous and semisolid or solid samples, use of test sample sizes of 5-25 g, adoption of alternative weighed water standardization, use of chloroform-methanol (1 + 1) or (2 + 1) premixed solvent, and use of reagent dilution for low water samples. The method has been adopted official first action by AOAC.
Liquid Chromatographic Determination of Benomyl in Wettable Powders: Collaborative Study
Authors: Teubert Wyatt E , Stringham Rodger W ,   Collaborators:, Bradway D E , Deubert K H , Folsom B , Hayes E H , Jaworski J , Jurgens D , Korger P D , Pilz-Weiskopf C , Plunkett R W , Stroh S
Published: February 2020

A simple and rapid determination of benomyl in wettable powders was tested by 10 collaborators. Formulations of benomyl are extracted into acetonitrile containing 3% n-butyl isocyanate, filtered, and chromatographed on a reverse phase (C-18) column with a minimum of 1000 plates. Benomyl is detected at 290 nm and quantitated by peak height. Three closely matched pairs of benomyl formulations were assayed along with a duplicate pair of 9 8% technical benomyl. The coefficients of variation were 1.20% for the 50% wettable powder, 5.89% for the 10% benomyl formulation with 50% captan, and 2.49% for a formulation of 6% benomyl with 10% captan and 50% lindane. Analysis of the technical benomyl gave a coefficient of variation of 1.52%. Collaborators stated the method was simple, rapid, and reproducible, and the statistical analysis showed it to be precise and free from expected interferences. The method has been adopted official first action.
Liquid Chromatographic Determination of Sugars in Licorice Products
Authors: Vora Pramathesh S , Tuorto Raymond M
Published: February 2020

The classical methods for determining sugars in licorice products are nonspecific, have limited application, and are time consuming, requiring about 2½ h to analyze one sample. A rapid, quantitative liquid chromatographic method has been developed for determining sugars in a variety of licorice products. The method is specific for quantifying 4 component sugars, sucrose, fructose, glucose, and maltose, in about 15 min. Sample preparation is simple; no pretreatment or prereaction is required before injecting an aliquot for LC determination. Fructose, glucose, sucrose, and maltose are quantified and determined by comparison with a sugar standard under the same conditions. Coefficient of variation values for the method ranged from 1.2 to 11.3% for the 5 samples analyzed. Comparison of the classical method with the LC method showed that higher values are obtained by the classical method for both sucrose content and total reducing sugar content.
High Temperature Purge and Trap Procedure for Determining Seven Volatile N-Nitrosamines in Animal Feed, Using Gas Chromatography/Thermal Energy Analyzer
Authors: Billedeau Stanley M , Thompson Harold C , Hansen Eugene B , Miller Barbara J
Published: February 2020

A rapid and sensitive procedure is described for determining 4 N- nitrosodialkylamines (dimethyl, diethyl, dipropyl, and dibutyl) and the N-nitroso analogs of piperidine, pyrrolidine, and morpholine in animal feed. The volatile N-nitrosamines were isolated by using a modified high temperature purge and trap apparatus designed for multiple sample cleanup. The feed sample was mixed with mineral oil and a nitrosation inhibitor, and the N-nitrosamines were purged onto a ThermoSorb/N cartridge, eluted with acetone–dichloromethane (1 + 1), and determined by gas chromatography, using a thermal energy analyzer. The effects of purge rate, purge time, and temperature on recovery are discussed. Feed samples spiked with 10, 50, and 200 ppb of the 7 N-nitroso compounds yielded recoveries ranging from 70 to 97%, with precision ranging from 1.3 to 5.4% and minimum detectable levels in the low parts-per-billion range.
Survey of Fresh Vegetables for Nematodes, Amoebae, and Salmonella
Authors: Rude Richard A , Jackson George J , Bier Jeffrey W , Sawyer Thomas K , Risty Norris G
Published: February 2020

Contamination by nematodes, amoebae, and bacteria of the genus Salmonella was estimated in a 2-year survey of salad vegetables obtained from wholesale and retail sources. The vegetables examined were cucumbers, cabbage, lettuce, celery, carrots, radishes, tomatoes, mushrooms, cauliflower, and spinach. Nematode eggs and larvae were recovered by the Nacconol-ether centrifugation method. Some nematode eggs were identified as parasitic Ascaris sp.; the majority of larval nematodes were thought to be soil-dwelling species. Amoebae were recovered by rinsing the vegetables with distilled water, centrifuging the rinse water, and transferring the sediment to agar plates on which a bacterial lawn had previously been grown; trophozoites identified as the potentially pathogenic species—Acanthamoeba polyphaga, A. rhysodes, and A. castellanii–were the most common amoebae recovered on the plates. Salmonella spp. were grown from 4 of 50 samples.
Comparison of Semiautomated Method with Official Optical Somatic Cell Counting Method III for Determining Somatic Cells in Milk
Authors: Mochrie Richard D , Dickey David A
Published: February 2020

The new method specifying the Fossomatic-90 differs from the official method, 46.105–46.109, in that the modified instrument includes a halogen lamp; a semiconductor photoelectric detector; a less expensive, bench-top cabinet; manual injection of a larger sample, and a reduced capacity. The new instrument was compared with 2 optical somatic cell counters in routine use. On each of 3 days, 12 subsamples were prepared for each of 5 cell count levels from AM milk with half kept fresh and half preserved with 0.05% potassium dichromate. Subsamples were refrigerated and read 30+ h post-collection. Duplicate sets were read in random order on each machine daily (CV 0.77%). Two sets of slides read by 2 technicians each (strip reticle on 2 smears/slide) gave geometric mean direct microscopic somatic cell count (DMSCC) levels of 296, 526, 772, 930, and 1438 th/mL. Within-technician CV values (from day-level means) ranged from 1.6S to 2.28%. Geometric mean cells in th/mL on the new machine were significantly higher than those on the other two (674 vs 621) and were closer to the DMSCC (694). On the new machine, cell counts were 8.5% greater than on the original machines, were only 2.9% lower than the DMSCC, and showed no significant evidence of bias. Preserved samples averaged slightly greater than fresh (5.3%) but only on the original machines. Carryover by covariance analysis was insignificant. Except for cell levels, high machine precision (error CV value of 1.18%) gave differences with statistical but not practical significance, even for regulatory laboratories.
Effect of Sodium Chloride and Potassium Chloride on Growth Response of Yeasts Saccharomyces uvarum and Kloeckera brevis to Free Vitamin B6
Authors: Guilarte Tomas R
Published: February 2020

Acid hydrolysis is the most commonly used extraction procedure for the microbiological assay of vitamin B6 in food samples. Because NaCl or KC1 is formed as a result of the extraction procedure, these 2 salts were tested as possible agents that may influence the growth response of the yeasts Saccharomyces uvarum and Kloeckera brevis. Results indicate that NaCl and KC1 do effect the growth response of these 2 yeasts, depending on the salt concentration and the B6 vitamer present.
Spectrophotometric Determination of Cyanoglucosides in Cassava
Authors: Nambisan Bala , Sundaresan Sukumaran
Published: February 2020

A new method is reported for determination of cyanoglucosides in cassava. The method is simple, rapid, and sensitive. Ten g cassava tuber is homogenized with warm (65–70°C) 80% ethanol (1 + 6, w/v) to extract cyanoglucosides (CNG). The ethanol is evaporated, and an aliquot of the extract (0.1–0.2 mL) is incubated with added linamarase in pH 6.0 phosphate buffer for 15 min at 30°C. The reaction is stopped by adding 0.2N sodium hydroxide, the solution is neutralized, and cyanide is estimated by adding chloramine T and barbituric acid–pyridine reagent and measuring the absorbance at 570 nm. Complete CNG extraction and rapid inactivation of endogenous linamarase is possible with 80% ethanol. There is no interference from extractives in the linamarase reaction or in the estimation of cyanide. Recovery of added linamarin (as cyanide) is 98% by this assay. The minimum detection limit of cyanide in the assay is 0.1 μg/mL.
Determination of Fluoride in Fluoride Tablets and Solutions by Ion-Selective Electrode: Collaborative Study
Authors: Marzilli John R ,   Collaborators:, Acampora F L , Alexander L R , Alpert M Y , Baetz R A , Bohm G , Donovan J J , Landskov A O , McNerney F G , Simon P J , Tobias D Y , Votta R J
Published: February 2020

A proposed method using the fluoride (F) ion-selective electrode has been developed for determining the fluoride ion concentration in tablets and solutions containing sodium fluoride. The method has been subjected to collaborative study. Eight samples consisting of 2 authentic fluoride solutions, 2 commercial fluoride solutions, and 4 commercial fluoride tablets were sent to each of 11 collaborators together with a copy of the method. Single assays on the authentic fluoride solutions known to contain 1 mg F/5 mL were performed with average recoveries of 99.5 and 99.6% and relative coefficients of variation (CV) of 2.11 and 1.91%, respectively. Single assays of 2 commercial fluoride solutions declared at 1 mg F/5 mL gave mean values of 0.994 and 0.990 mg and relative CV values of 1.88 and 2.36%, respectively. Single assays of 2 commercial fluoride tablet preparations declared at 0.5 mg F gave mean values of 0.485 and 0.478 mg and relative CV values of 3.12 and 3.71 %, respectively. Single assays of 2 commercial fluoride tablet preparations declared at 1 mg F gave mean values of 0.991 and 0.981 mg and relative CV values of 2.99 and 2.85%, respectively. The method has been adopted official first action.
Effect of Residual Ascorbate on Determination of Nitrite in Commercial Cured Meat Products
Authors: Fox Jay B , Doerr Robert C , Gates Robert
Published: February 2020

Residual ascorbate in cured meat slurries results in different amounts of pigment being produced from different Griess reagent combinations. The phenomenon was used to study residual ascorbate in commercial cured meat products which had a variety of textures, acidities, moisture and meat content, fat, homogeneity, initial nitrite, and processing conditions. Diluting and heating the samples according to the AOAC procedure did not completely eliminate the ascorbate interference, but making the sample alkaline did. Determining nitrite separately in supernate and precipitate from the first dilution showed the effect of heating to be the elimination of interferences and solubilization or extraction of nitrite from the precipitate.
Liquid Chromatographic Determination of Sugars in Licorice Extracts: Collaborative Study
Authors: Vora Pramathesh S , Tuorto Raymond M ,   Collaborators:, Atchley F , Conway W , Hodge B , Norris K , Price B , Shuford C
Published: February 2020

A collaborative study to determine fructose, glucose, sucrose, and maltose in a variety of licorice extracts has been performed using liquid chromatography. Six collaborators participated in the study, and each collaborator was sent 5 samples which were analyzed in blind replicates. A practice sample was used with a specific range of 8-10% fructose, 10-12% glucose, and 5-7% sucrose. The individual sugar concentration of the 5 samples ranged from 2.0 to 10%. AH samples were quantitated by comparing results with a pure sugar standard containing fructose, glucose, sucrose, and maltose and analyzed under the same conditions. No significant problems were encountered running the practice or other samples despite the wide range of instruments and columns used. Results showed less deviation within laboratories compared with results obtained among laboratories. The method has been adopted official first action.
Genetic Methods for the Detection of Microbial Pathogens. Identification of Enterotoxigenic Escherichia coli by DNA Colony Hybridization: Collaborative Study
Authors: Hill Walter E , Payne William L ,   Collaborators:, Crouch R J , Davis V M , English L L , Ferreira J L , Gemski P , Jagow J A , Moseley S L , Noah C W , Silver R P , Singleton E , Weagant S D , Wohlhieter J A , Womble D D , Zink D L
Published: February 2020

Enteropathogenic Escherichia coli strains may produce a cholera-like, heat-labile enterotoxin (LT) as a virulence factor. The gene that codes for LT can be purified by recombinant DNA techniques and used as a genetic probe for DNA hybridization. These probes detect enterotoxigenic strains as well as strains that may not manifest toxin production but carry the genetic information to do so. In this study, 13 laboratories tested 3 known and 25 unknown (10 positive and 15 negative) cultures off. coli for the presence of the LT gene. The isolates had been tested and classified by the mouse Y-l adrenal cell test and an enzyme-linked immunosorbent assay. Cultures were spotted on nitrocellulose filters on MacConkey agar and incubated. Colonies were lysed in situ and their DNA was hybridized to 32P-labeled, purified LT gene DNA (provided to the collaborators). Positive colonies were identified by autoradiography. Of 325 samples, 315 (96.9%) were identified correctly and 10 were misclassified; there were 6 false negative and 4 false positive identifications. Chi-square values indicated that the method agreed with the previous classification and was equally efficient in distinguishing positive and negative samples (95.7 and 98.1%, respectively). The method has been adopted official first action.
Liquid Chromatography of Liquid Formulations Containing 2,4-D, Dicamba, and MCPP as Their Salts: Collaborative Study
Authors: Grorud Robert B , Forrette John E ,   Collaborators:, Bajovich J , Bath R L , Billings J L , Counts J L , Diuquid J , Foster B E , Hodgins E , Stevens T S , Stringham R W , Vernetti J B
Published: February 2020

A liquid chromatographic method for any liquid mixture of the 3 herbicides 2,4-D, MCPP, and dicamba, found in commercial formulations, has been collaboratively studied. Each collaborator received 4 samples, 3 of which were ternary formulations and one a binary formulation of amine salts. Concentrations in the formulations range from 0.02 to 2.32% for dicamba, 0.32 to 21.7% for 2,4-D, and 0.22 to 11.6% for MCPP. A binary solvent system and the use of a specified 25 cm column of RP 10 μm in the reverse phase ion suppression mode will selectively quantitate each herbicide, separating many impurities found in the technical products. Standard deviations in each of 11 columns of results obtained indicate good precision. The method has been adopted official first action.
Simple, Rapid Method for Determination of Total Extractable Fat in Canned Pet Foods
Authors: Maxwell Robert J
Published: February 2020

The rapid column method described, unlike AOAC method 7.056, determines both neutral ("crude") and total fat in canned pet foods, and uses nonflammable solvent mixtures and simple laboratory equipment. Neutral fat values are obtained by eluting the column with dichloromethane, whereas total fat values are determined by using dichloromethane-methanol (9 + 1). For 7 samples analyzed in triplicate, fat ranged from 2.9 to 10.8%. Neutral fat values by the dry column method were significantly lower (P < 0.05) than were those by 7.056 (6.29 vs 6.49), although these differences were practically unimportant. Total fat determinations by the dry column method and by 7.056 yielded overall means of 7.40 and 6.49%, respectively. The 0.91% mean difference is significant (P < 0.01) and represents a more complete extraction of polar lipids by the proposed method.
Gas Chromatographic and Mass Spectrometric Determination of Ametryn and Its N-Dealkylated Products
Authors: Bardalaye Promode C , Wheeler Willis B , Templeton James L
Published: February 2020

Gas chromatographic and mass spectrometric properties of ametryn and its N-dealkylated products were studied to establish the potential use in a recently reported method describing the residue analyses of these compounds by gas chromatography with N-P detection. Electron impact mass spectra show base peaks at the molecular ion (M+), and methane chemical ionization mass spectra give base peaks at (M + 1) ion for all the compounds studied. Characteristic mass spectral fragmentations of ametryn, GS-11354, GS-11355, and GS-26831 are presented. Combined gas chromatography-mass spectrometry rather than gas chromatography alone provides unambiguous residue characterization. The technique also allows quantitation of ametryn and its N-dealkylated products that cochromatograph with interfering materials present in a complex substrate.
Liquid Chromatographic Determination of Benzoyl Peroxide in Acne Preparations
Authors: Chou Chih-Kuang , Locke David C
Published: February 2020

A rapid, precise, and accurate liquid chromatographic (LC) method is described for the determination of benzoyl peroxide (BP) in acne preparations. BP is extracted from a water dispersion of the preparation with dichloromethane (DCM), and an aliquot is eluted from a C-18 reverse phase LC column with acetonitrile-O.lOM aqueous NaCI04. Selective and sensitive quantitation is accomplished with a reductive mode electrochemical detector. This detector is an order of magnitude more sensitive than a 240 nm UV absorption detector; the lower limit of detection is 2 ng for a 4 μL injection. The recovery of BP is 99.4% and the detector response is linear to at least 2 μg per 4 μL injection.
Difference Spectrophotometric Estimation of Santonin
Authors: Habib Abdel-Azim M , Omar Abdalla A , Sarg Taha M
Published: February 2020

Santonin gives a characteristic alkaline vs acidic difference spectrum. This was used for its estimation in pharmaceuticals and in the crude drug. Santonin was first extracted and purified through a specific partition procedure; then the difference absorbance was measured either at the maximum, 285 nm, or the minimum, 242 nm. The percentage of santonin can be calculated either by reference to the difference absorbance of a reference santonin sample, treated similarly, or by making use of the determined absorptivity. Measurement at the maximum is advisable, especially when the crude drug is assayed, because natural contaminants may interfere with the difference absorbance at the minimum.
Determination of Pantothenic Acid, Biotin, and Vitamin B12 in Nutritional Products
Authors: Hudson Thomas S , Subramanian Shyamala , Allen Rebecca J
Published: February 2020

Until recently, liquid chromatographic (LC) methodology for pantothenic acid, biotin, and B12 (cyanocobalamin) has been only marginally successful. These vitamins are difficult to determine by conventional LC techniques and UV detection at 254 or 280 nm, because either the chromophore is inadequate for detection or interference from co-eluting vitamins is overwhelming. Biotin and B12 are usually present in pharmaceutical products at concentrations 100-1000 times lower than other commonly occurring water-soluble vitamins. Co-extraction of all water-soluble vitamins results in gross interferences, especially in LC when the interfering vitamins co-elute with biotin or B12. In addition, pantothenic acid and biotin are colorless in solution and do not exhibit strong UV absorption above 240 nm. As a result, they must be quantitated either by using a low UV wavelength for detection or by derivatizing the vitamin to obtain an adequate chromophore. A description of procedures for LC determination of pantothenic acid, panthenol, cyanocobalamin, and biotin in pharmaceutical products is presented. Pantothenic acid has been measured by using both a derivatization technique and low UV wavelength detection. Biotin has been quantitated by using low UV wavelength detection. The limitations of these techniques are also discussed. Chromatographic separation of cyanocobalamin is complicated by co-eluting vitamins such as riboflavin. It is detected by using the 546 nm wavelength where riboflavin does not interfere.
Fecal Pellets from a Commensal Shrew (Suncus murinus) and a House Gecko (Gekkonidae)
Authors: Olsen Alan R
Published: February 2020

Examination of excreta pellets from commensal shrews (Suncus murinus) and tropical house geckos (Gekkonidae) showed several characteristics that were useful in distinguishing these pellets from those of commensal rodents. Commensal shrew pellets contained a large number of embedded insect fragments but no embedded hairs. Each shrew pellet was associated with a distinctive circular stain on the floor or container surface where it was found. Gecko pellets were composed entirely of tightly packed insect fragments with no intervening matrix. In contrast to both shrew and rodent pellets, there was no surface mucous coating. A small white body containing uric acid adhered to one end of each gecko pellet.
Determination of Total Dietary Fiber in Foods, Food Products, and Total Diets: Interlaboratory Study
Authors: Prosky Leon , Asp Nils-Georg , Furda Ivan , Devries Jonathan W , Schweizer Thomas F , Harland Barbara F
Published: February 2020

An interlaboratory study was conducted to determine the total dietary fiber (TDF) content of food, food products, and total diets, using a combination of enzymatic and gravimetric procedures. Thirteen unknown products including 2 mixed diets (one lacto-ovo vegetarian and the other nonvegetarian) were analyzed by 32 analysts. Duplicate samples of dried foods were gelatinized with Termamyl, a heat-stable alphaam) lase, and then enzymatically digested with protease and amyloglucosidase to remove the protein and starch present in the sample. Four volumes of 95% ethanol were added to precipitate the soluble dietary fiber. The total residue was filtered, and then washed with 74% ethanol, 95% ethanol, and acetone. After drying, the residue was weighed. One of the duplicates was analyzed for protein, and the other was ashed at 525°C and the ash was measured. TDF was calculated as the weight of the residue less the weight of protein and ash. Coefficients of variation for 10 of the samples ranged from 2.95 to 26.39%. For 3 of the samples high coefficients of variation were obtained. The results compared satisfactorily with those obtained previously by the best method available for the individual foods studied.
Liquid Chromatographic Determination of Sodium Fluoroacetate (Compound 1080) in Meat Baits and Formulations
Authors: Kramer Harvey L
Published: February 2020

A liquid chromatographic (LC) method is described for the determination of sodium fluoroacetate in meat baits and formulations. Baits were extracted with water, ultrafiltered, partitioned into butanone, back-partitioned into dilute base, and diluted with acetonitrile. Aqueous formulations of 1080 were diluted with acetonitrile. The solutions were esterified with p-bromophenacyl bromide, using crown ether catalysis, and chromatographed on a 10 μm reverse phase column. Ultraviolet absorbance was monitored at 260 nm. Samples spiked to contain 1 mg and 10 mg 1080/100 g meat gave recoveries of 84.0-103.4%.
Chemical Confirmatory Tests for Ochratoxin A, Citrinin, Penicillic Acid, Sterigmatocystin, and Zearalenone Performed Directly on Thin Layer Chromatographic Plates
Authors: Goliński Piotr , Grabarkiewicz-Szczęsna Jadwiga
Published: February 2020

Published tests have been improved and a new procedure is described for chemical confirmation of mycotoxins directly on thin layer plates. After extraction and preliminary cleanup chromatography with nhexane or chloroform, the mycotoxins ochratoxin A, citrinin, penicillic acid, sterigmatocystin, and zearalenone were easily separated by thin layer chromatography (TLC) using toluene-ethyl acetate-90% formic acid (6 + 3 + 1) developing solvent. In chemical confirmatory methods, the developed chromatogram was exposed to vapors of pyridine, acetic anhydride, or a mixture, or the mycotoxins were over-spotted. With this treatment, ochratoxin A, citrinin, penicillic acid, and zearalenone were converted to new fluorescent compounds, and observed under 365 nm light after re-chromatography with the same developing solvent. Sterigmatocystin was confirmed chemically using TLC plates impregnated with 0.6N H2S04 or 10% oxalic acid in methanol. The described procedures are satisfactory for confirming mycotoxins present in standards, artificially contaminated grain samples (barley, corn, oat, rye, and wheat), and extracts from both fungal cultures and naturally contaminated grain samples.
Liquid Chromatographic Determination of Allopurinol in Tablets: Collaborative Study
Authors: Shostak Donald ,   Collaborators:, Uribe M P , Poplawski T , Savage T S , Reed G D , Smith F S , Krieger D , Roberts S E
Published: February 2020

A liquid chromatographic method for the determination of allopurinolin tablets was collaboratively studied by 7 laboratories. The methoduses a C,8 reverse phase column, a 0.05M ammonium phosphate mobilephase, hypoxanthine as the internal standard, and photometric detectionat 254 nm. Collaborators were supplied with samples of 2 commercialtablets and 1 synthetic tablet powder. The mean recovery value of allopurinol from the synthetic tablet powder was 100.0%. The combinedmean coefficient of variation for all 3 types of sample analyzedwas less than 2%. The method has been adopted official first action.
Analytical Methods for Determining Ascorbic Acid in Biological Samples, Food Products, and Pharmaceuticals
Authors: Pachla Lawrence A , Reynolds Donald L , Kissinger Peter T
Published: February 2020

Over the last decade, numerous publications have appeared describing \ analyses for ascorbic acid in food products, pharmaceuticals, and biological samples. This review focuses on the chemistry associated with many of these procedures. The papers discussed have historical importance, are important to understanding the method, or have significantly advanced ascorbic acid analysis. The review has 4 major, sections: spectroscopic, electrochemical, enzymatic, and chromatographic methods of analysis.
Indirect Enzyme-Linked Immunosorbent Assay for Saxitoxin in Shellfish
Authors: Chu Fun S , Fan Titan S L
Published: February 2020

An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of saxitoxin (STX). Antibodies against STX were demonstrated in rabbits 5 weeks after immunizing with STX-bovine serum albumin (STX-HCHO-BSA). In the ELISA, STX-HCHO-BSA or polylysine-STX was coated onto the microtiter plate, followed by incubation with standard toxin and anti-STX antibody. The amount of antibody bound to the solid phase was determined by incubation with goat anti-rabbit IgG peroxidase conjugate and a reaction with chromogenic substrate. Competitive indirect ELISA revealed that the antiserum did not cross-react with either carbamoyl-neo-STX-suIfate or tetrodotoxin. The antibodies for STX cross-reacted with decarbamoyl- STX and neo-STX about 56% and 16% as much as they did with STX, respectively. The lower detection limits for STX, decarbamoyl-STX, and neo-STX in this sytem were about 25, 45, and 156 pg per assay, respectively. When STX added to clams or mussels was assayed, the detection limit for STX was about 50-100 ppb, and recoveries were in the range of 86.8-107%.
Extraction of Organic Acids by Ion-Pair Formation with Tri-w-Octylamine. Part 7. Comparison of Methods for Extraction of Synthetic Dyes from Yogurt
Authors: Puttemans Marc L , Voogt M De , Dryon Louis , Massart Desire
Published: February 2020

Synthetic dyes were extracted from yogurt by different methods, but all methods had in common a liberation of dyes from the food followed by ion-pair formation with tri-n-octylamine. Extraction with pH 5.5 phosphate buffer gave high recoveries for 5 of the 7 dyes investigated and was relatively fast. Precipitation of proteins followed by polyamide adsorption and desorption gave high yields for all the dyes but was tedious and long.
Gas Chromatographic Determination of Trans Unsaturation in Margarine: Collaborative Study
Authors: Gildenberg Lawrence , Firestone David
Published: February 2020

An international collaborative study of a gas chromatographic (GC) method for the determination of trans unsaturation in margarine was conducted in 1980. Thirteen collaborators analyzed a set of 2 of 3 known mixtures of methyl esters and 4 margarine methyl ester samples. Two of the margarine methyl ester samples were blind duplicates. The experimental data were subjected to statistical analysis to determine within- and between-laboratory variation. The statistical data were in excellent agreement with data from a collaborative study of the AOACIUPAC GC method for the determination of methyl esters of fatty acids. Coefficients of variation (CVs) for components in the range of 4-40% were comparable (CV 2-6% for soybean oil methyl esters (AOAC-IUPAC study) as well as for margarine methyl esters (this study)). Good recoveries of total trans acids were obtained and betweenlaboratory as well as within-laboratory CVs were consistently better for the determination of total trans acids by GC vs infrared analysis. The GC method for determining trans unsaturation in margarine has been adopted official first action.
Comparison of Interlaboratory Variation in Amino Acid Analysis and Rat Growth Assays for Evaluating Protein Quality
Authors: Sarwar Ghulam , Blair Robert , Friedman Mendel , Gumbmann Michael R , Hackler Ross L , Pellett Peter L , Smith Trevor K
Published: February 2020

Estimates of inter- and intralaboratory variation of protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR), relative NPR (RNPR), and nitrogen utilization (NU) were compared with those of amino acid analysis in the same batches of 7 protein sources (ANRC casein, egg white solids, minced beef, soy assay protein, rapeseed protein concentrate, pea flour, and whole wheat flour). Interlaboratory variation (estimated as between-laboratories coefficients of variation, CV) of NPR and RNPR (up to 6.0%) was lower than that of PER (up to 20.2%) and RPER (up to 18.5%). The interlaboratory determination of NPR and RNPR was also more reproducible than that of most essential amino acids (CV up to 10.0%), especially tryptophan (CV up to 23.7%), cystine (CV up to 17.6%), and methionine (CV up to 16.1%). Intralaboratory variation (estimated as within-laboratories CV) of amino acid analysis (up to 4.7%), however, was comparable to that of protein quality indices in most protein sources (up to 6.0%). The significant (P <0.01) positive correlations (r = 0.68-0.74) between amino acid scores and protein quality indices based on rat growth were further improved when amino acid scores were corrected for digestibility of protein (r = 0.73-0.78) or individual amino acids (r = 0.79- 0.82).
Amperometric Determination of Propantheline Bromide in a Flowing Stream at the Glassy Carbon Electrode
Authors: Shah Mumtaz H , Stewart James T
Published: February 2020

University of Georgia, College of Pharmacy, Department of Medicinal Chemistry, Athens, GA 30602 A flow-injection method is presented for the determination of propantheline bromide, based on electrochemical oxidation at the glassy carbon electrode. The amperometric method can determine propantheline bromide in the presence of phenobarbital, commonly found in its combination dosage forms. The procedure is stability-indicating for propantheline when an ether extraction of the dosage form is done before amperometric detection. At the electrode potential of + 1400 mV, the calibration curve is linear in the 2-16 p.g/mL concentration range, and minimum detectability is 20 ng (signal-to-noise ratio of 2). When applied to the analysis of propantheline bromide in selected pharmaceutical dosage forms, the method shows good accuracy and precision. Although automation was not used in this study, the method could readily be incorporated in automated systems because it uses the technique of continuous analysis in a flowing stream
Spectrophotometric Determination of Phosphine Residues in Rice
Authors: Rangaswamy Jois R , Muthu Mysore
Published: February 2020

Phosphine residues were determined in 2 types of rice samples, raw polished and parboiled. The yellow chromophore due to phosphine from raw polished rice had 2 absorption maxima, a strong one at 370- 380 nm and a weaker one at 400-410 nm. The chromophore from parboiled rice also had 2, one at 390-400 nm and the other at 410-420 nm. A closed system containing rice and a phosphine tablet or powder yielded 93-99% recovery of fortified phosphine. At any given dose of phosphine, parboiled rice retained a higher amount of residue after aeration than did raw polished rice.
Liquid Chromatographic Determination of 2-(2-Quinolinyl)-l/7-indene-l,3-[2#]-dione and Other Organic-Soluble Matter in D&C Yellow No. 10
Authors: Goldberg Allen L
Published: February 2020

A sensitive, reproducible method that uses an Extrelut QE column and liquid chromatography (LC) in the reverse phase mode is described forthe determination of 2-(2-quinoIinyl)-l//-indene-l,3-[2JJ]-dione and other organic-soluble matter found in D&C Yellow No. 10. With this method the organic-soluble matter is extracted from D&C Yellow No. 10 on an Extrelut QE column, and the extract is concentrated and analyzed by LC. Recoveries averaged 104% for 2-(2-quinolinyl)-l#- indene-l,3-[2tf]-dione added to purified D&C Yellow No. 10 at levels ranging from 0.50 to 5.96 ppm.
Elemental Analysis of Plant Tissue by Plasma Emission Spectroscopy: Collaborative Study
Authors: Isaac Robert A , Johnson William C
Published: February 2020

Fourteen laboratories participated in a collaborative study of 6 homogeneous plant tissue samples to determine the elements P, K, Ca, Mg, Mn, Fe, Al, B, Cu, Zn, and Na by plasma emission spectroscopy. Samples were dry ashed using AOAC method 3.007(a) (13th Ed.). An NBS citrus leaf standard was prepared and a portion of the resulting solution was sent to each collaborator to evaluate sample preparation errors independent of instrument error. Coefficients of variation were better than those obtained in an earlier collaborative study on multielement analysis by spark emission spectroscopy. The plasma emission method has been adopted official first action for determination of P, K, Ca, Mg, Mn, B, Cu, and Zn in plant tissues.
Liquid Chromatographic Determination of Morphine Sulfate and Some Contaminants in Injections and Bulk Drug Material
Authors: Jhangiani Rita k , Bello Ada C
Published: February 2020

A liquid chromatographic (LC) procedure is described for the assay of morphine sulfate in bulk drug material and injection solutions. The bulk drug and injection samples are prepared by direct dilution with LC mobile solvent. The average bulk drug purity (5 manufacturers) determined by the LC method was 99.9% with a difference of 0.1% from the average purity (anhydrous) found by the official USP XX procedure. The average LC recovery (19 studies) of morphine sulfate added to injection samples was 99.4% with a coefficient of variation (CV) of 1.14%. Morphine sulfate content was determined in triplicate for 53 injection samples (1-15 mg morphine sulfate/mL) formulated by 6 manufacturers, using the proposed LC procedure. Individual sample CV (n = 3) averaged 1.14%. The LC method is simple and specific for morphine sulfate. Major degradation products, preservatives, and some contaminants and related compounds are separated during LC.
Liquid Chromatographic Determination of Triadimefon in Technical and Formulated Products: Collaborative Study
Authors: Slahck Stephen C
Published: February 2020

A liquid chromatographic method for the determination of triadimefon (Bayleton™) in triadimefon technical and formulated products has been developed and subjected to a collaborative study with 7 participating collaborators. Formulations were extracted with mobile solvent and analyzed by normal phase chromatography, with 4-chlorophenyl sulfoxide as an internal standard. Collaborators were furnished with standards and samples of technical products, 50% wettable powders, and 25% wettable powders for analysis. Coefficients of variation of the values obtained on these samples were 1.42, 0.82, and 1.05%, respectively. The method has been adopted official first action.