bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectrophotometric Determination of Hydralazine Hydrochloride Tablets Using Ninhydrin
Authors: Dutt Manesh C , Ng Tju-Lik , Long Lian-Tun 
Published: February 2020

Abstract
A method is described for the assay of hydralazine HC1 in tablets, based on the colored product formed by the reaction between hydralazine and ninhydrin. The reaction is conducted at room temperature in a pH 3 buffer solution and the colored product is measured spectrophotometrically at the absorption maximum at 442 nm. Under the stipulated conditions, this reaction is highly specific for hydralazine and is not affected by other drugs which may be used in combination with hydralazine. Results of infrared and mass spectrometric studies suggested that the colored product is a hydrazone. Ultraviolet spectrophotometry also showed that dilute solutions of hydralazine degrade rapidly in the presence of alcohols.
Five-Year Study of Mycotoxins in Virginia Wheat and Dent Corn
Authors: Shotwell Odette L , Hesseltine Clifford W 
Published: February 2020

Abstract
Every year during the 5-year period 1976-1980, approximately 100 samples each of corn and wheat from trucks delivering the grains at elevators in Virginia were collected by personnel of the Federal Grain Inspection Service and shipped to NRRC. Samples were analyzed as soon as possible for aflatoxin, zearalenone, and ochratoxin A. The 3 mycotoxins were not detected in any wheat sample. Zearalenone and ochratoxin A were not found in any corn sample; however, aflatoxin was detected in at least 25% of the corn samples from every crop year. In 1976-1980, the incidence of aflatoxin at levels of 20 ng/g or more (the Food and Drug Administration guideline) ranged from 18 to 61%; aflatoxin incidence above 100 ng/g was 5-29%. The average aflatoxin levels in corn samples collected in the 5 years varied from 21 to 137 ng/g. Moisture content of the samples was not determined, so aflatoxin levels given may be higher than they were at harvest. However, there are obviously differences from year to year. In freshly harvested corn samples collected by fieldmen of the Statistical Reporting Service in yield surveys in 1978 and 1979, aflatoxin incidence above the FDA guideline was 10 and 13%, and above 100 ng/g was 4 and 7%. The average aflatoxin level in all samples collected in 1978 was 13 ng/g and in 1979, 36 ng/g. Some aflatoxin can be expected yearly in Virginia corn, but the incidence and levels vary from year to year.
Automated Sample Cleanup for Pesticide Multiresidue Determination. I. Evaluation of Solvent Partitioning Module
Authors: Gretch Fred M , Rosen Joseph D 
Published: February 2020

Abstract
An automated continuous flow procedure is described that improves the cost effectiveness and precision of AOAC methodology for multiresidue pesticide determinations in nonfatty foods. Individual modules capable of performing automated solvent partitioning and automated column chromatography were constructed and integrated into a continuous flow system. Data are presented comparing the recoveries and precision for the determination of 8 pesticides (aldrin, dieldrin, p,p’ - DDT, ethion, heptachlor epoxide, lindane, parathion, and ronnel) partitioned from 2 food crops (spinach and tomatoes) by both the manual and automated procedures.
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

Abstract
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

Abstract
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

Abstract
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 &gt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.