bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semiautomated Method for Riboflavin in Food Products: Collaborative Study
Authors: Egberg David C 
Published: February 2020

Abstract
A collaborative study was conducted comparing a semiautomated riboflavin method with a manual riboflavin method for 10 food products. Six laboratories provided results from the semiautomated method and 16 laboratories used the manual technique. The semiautomated method was more repeatable within a laboratory and more reproducible between laboratories than was the manual method. The semiautomated method results compared favorably with the manual method for all 10 products.
Atomic Absorption Determination of Tin in Foods: Collaborative Study
Authors: Elkins Edgar R , Sulek Arlene 
Published: February 2020

Abstract
Samples of green beans, applesauce, and a fruit juice were fortified with tin at 3 levels. Collaborators were asked to digest the samples, using HNO3-H2SO4, add methanol to enhance the absorption signal, and aspirate directly, using a nitrous oxide-acetylene flame. Results were received from 8 laboratories including 4 from Europe. However, only 6 laboratories used the prescribed methodology. All results were considered acceptable. The method has been adopted as interim official first action.
Lead, Fluoride, and Other Elements in Bonemeal Supplements
Authors: Capar Stephen G , Gould John H 
Published: February 2020

Abstract
The Pb, Cd, F, Al, Cr, Cu, Fe, Mn, Mo, Ni, Ti, and Zn content of 20 commercial bonemeal supplements was determined. Samples were mineralized with nitric and perchloric acids prior to determination of all elements except F, for which a diffusion method was used. Pb and Cd were determined by differential pulse anodic stripping voltammetry, F was measured using an ion selective electrode, and all other elements were determined by inductively coupled argon plasma spectroscopy. The mean recoveries of Pb and F were 97 and 99%, respectively. The concentration range of Pb was 1.5-8.7 μg/g. Cd was quantitated in only one sample at a level of 2.5 μg/g; all other samples were estimated to contain &lt;0.05 μg Cd/g. The concentration of F ranged from 261 to 921 μg/g.
Microdiffusion and Fluoride-Specific Electrode Determination of Fluoride in Foods
Authors: Dabeka Robert W , Mckenzie Arthur D , Conacher Henry B S 
Published: February 2020

Abstract
A simple and accurate method was developed for routine determination of fluoride in foods. Hydrogen fluoride is diffused 20 hr at 50°C from fresh or freeze-dried samples (0.1 g dry wt) in polystyrene petri dishes containing 2 mL 40% HClO4 and 0.3 g Ag2SO4, and is absorbed on the lids, previously spotted with 0.1 mL 0.5M NaOH. The absorbent layer is dissolved in 2 mL buffer solution, and the fluoride is measured potentiometrically. The method was verified by analysis of NBS Standard Reference Materials; recovery from 28 spiked infant foods (average = 99%, range — 75-135%); and comparison of results with colorimetry results for the same diffusates, after modification to handle 1 g samples. Relative standard deviations varied from 4 to 20% day to day. Detection limits were below 0.05 μg/g dry weight.
Liquid Chromatographic Determination of Methscopolamine Bromide in Various Veterinary Formulations
Authors: Hartman Patrick A 
Published: February 2020

Abstract
A reverse phase paired ion liquid chromatographic procedure is described for determining methscopolamine bromide (Pamine) in the presence of neomycin sulfate in 5 veterinary formulations (Biosol M). Methscopolamine bromide is separated from neomycin sulfate and other formulation excipients by extraction into ethanol. The sample preparations are then concentrated and dissolved in water before chromatography. Recovery of methscopolamine bromide added to 5 placebo formulations ranged from 99.7 to 100.7%, with relative standard deviations of less than 2%. Specificity of the method with regard to potential degradation products is demonstrated.
Colorimetric Determination of Hydralazine with 9-Chloroacridine
Authors: Stewart James T , Chang Yu-Chu 
Published: February 2020

Abstract
A spectrophotometric assay for hydralazine hydrochloride based on the interaction of the drug with 9-chloroacridine has been developed. The interaction shows an absorption maximum at 460 nm and is affected by temperature, heating time, and quantity of acridine reagent used. Color development is maximum when the drug is heated in the presence of a 30-fold molar excess of the acridine in a 50±l°C water bath for 1 hr. The method detects hydralazine hydrochloride in the 10-5-10-6M range with sensitivity to 0.2 μ/mL and 3-4% accuracy. Typical calibration data obtained from linear regression analysis of absorbance at various drug concentrations show r = 0.9997 (n=6). Hydralazine can be determined in dosage forms that also contain varying quantities of reserpine and hydrochlorothiazide. The 9-chloroacridine method is as sensitive as other spectrophotometric procedures for hydralazine but also more accurate and precise, and involves fewer manipulative steps.
Determination of Edrophonium Chloride Injection USP in the Presence of Preservatives
Authors: Hamill Thomas W 
Published: February 2020

Abstract
The determination of Edrophonium Chloride Injection involves a modification of a procedure for phenylephrine and offers an alternative to the compendial assay. Edrophonium chloride forms an ion-pair with di-(2-ethylhexyl) phosphoric acid which can be extracted with an immiscible solvent such as ether. When this procedure is coupled with partition chromatography, the drug can be isolated from preservatives and quantitatively determined by its ultraviolet absorbance. Recovery data on synthetic mixtures ranged from 99.8 to 101.9% and were in good agreement with the compendial method.
Colorimetric and Spectrophotometric Determination of Total and Non-phenolic Alkaloids in Ipeca and Its Formulations
Authors: Saleh Mohamed R I , El-Masry Sawsan , El-Shaer Nagwa 
Published: February 2020

Abstract
A simple method, requiring no chromatographic separation, is presented for the determination of the total and non-phenolic alkaloids in ipeca and its preparations. The complex formed between the alkaloid and methyl orange at pH 5.0 is extracted with chloroform and treated with 0.1N NaOH. The liberated dye, determined at 460 nm, is a measure of the total alkaloids. The chloroform phase remaining is treated with 0.1N H2SO4, and the acid extract is measured at 283 nm for the non-phenolic alkaloids, calculated as emetine. The proposed method was successfully applied to samples of ipeca powder, ipeca tincture, and 3 British Pharmaceutical Codex mixtures containing ipeca tincture, namely, ipecacuanha mixture, pediatric; ipecacuanha and ammonia mixture, pediatric; and belladonna and ipecacuanha mixture, pediatric. The proposed method compares favorably with the Egyptian Pharmacopoeia, British Pharmacopoeia, and USP methods and has a relative standard deviation of 1.54%. The present procedure is less time-consuming and requires about 45 and 90 min for the assay of ipeca tincture and powder, respectively. Only a small sample (0.2 mL tincture or 1.0 g powder) is required.
Spectrophotometric Determination of Piperazine and Its Salts in Pharmaceuticals
Authors: Abou-Ouf Abdel M , Walash Mohamed I , Rizk Mohamed S , Ibrahim Fawzia A 
Published: February 2020

Abstract
A spectrophotometric determination of piperazine and some of its salts is described. The method depends on the UV measurement of the N-nitroso derivatives formed by the interaction of piperazine with nitrous acid. The chromophore is developed by heating the reaction mixture at 80°C for 15 min, at pH 2.3-2.6. Beer's law is obeyed in the range 1-15 μg/mL.
Cleanup of Biological Samples for Determining p,p’-DDT and Its Metabolites
Authors: Ahmad Nazir 
Published: February 2020

Abstract
A method is described for extracting tissue samples with hexane-acetone and hydrolyzing the fat and protein with aqueous sodium hydroxide. p,p’-DDT and its metabolites are measured on a gas chromatograph with an electron capture detector after cleanup on an alumina column. The new cleanup procedure gives 98% recoveries for p,p’-DDT and its metabolites added to fat in vitro, compared with 84% recovery by a modified commonly used method. Comparison by Student's f-test of the new method with the modified method on 32 cattle biopsy, 46 bird, and 20 fish samples for in vivo incurred p,p’-DDT residues showed that the results by the new method were significantly higher at the 95% confidence level. Alkali-hydrolyzed extract did not contaminate the detector. The new procedure avoids the use of dimethylformamide and shortens the time of analyses. A correlation (r=0.68) was observed between the fat-soluble protein concentration of the n-hexane extract and the p,p’-DDT residues.
Gas-Liquid Chromatographic Determination of Bromide Ion in Lettuce: Interlaboratory Studies
Authors: Greve Peter A , Grevenstuk Willem B F 
Published: February 2020

Abstract
The gas-liquid chromatographic method for the determination of bromide ion, as originally described for grain by Heuser and Scudamore, was adapted for use on lettuce, and later on products of other vegetable or of animal origin. After optimization of the ashing and derivatization conditions, 2 interlaboratory studies were carried out in The Netherlands. In the first, a preparatory study, 6 laboratories investigated freeze-dried lettuce; in the second definitive study, 8 laboratories investigated both freeze-dried and fresh lettuce. Four lots of lettuce with bromide contents ranging from about 5 to about 200 mg/kg were investigated. Average bromide contents (mg/kg) and between-laboratory coefficients of variation were 5.6 (11.0%), 13.3 (18.4%), 29.9 (8.3%), and 209 (12.8%). The results obtained are normal for the type of work and the conditions of the study. The method will be recommended for regulatory use in The Netherlands and in international organizations.
Long-Term Storage of Microorganisms Used in Antimicrobial Effectiveness Tests
Authors: Cosgrove Raymond F 
Published: February 2020

Abstract
Liquid nitrogen storage of organisms designated in the U.S. Pharmacopeia (XIX) for the assessment of antimicrobial effectiveness is described. By use of simple apparatus and procedures, 85-95% viabilities of pre-frozen cells are attained immediately upon freezing. Viability levels have remained constant over a 3-year period and the use of such inocula has considerably improved the reliability of the test. The superiority of liquid nitrogen storage for microbial test inocula over other types of storage is discussed.
Equivalence of Microbiological and Hydroxylamine Methods of Analysis for Ampicillin Dosage Forms
Authors: Lin Song-Ling , Sutton Vincent J , Quraishi Mateen 
Published: February 2020

Abstract
Ampicillin formulations were assayed by microbiological and hydroxylamine methods to determine whether the hydroxylamine analytical method is a suitable substitute for the microbiological method. Paired assay results by the 2 analytical methods were obtained on different strengths of tablet, capsule, and suspension formulations containing ampicillin and ampicillin degradation compounds. Several statistical tests were used to assess the equivalence of the paired assay results. The data analyses indicate that the hydroxylamine method is a suitable substitute for the microbiological method for potency assays and stability studies of ampicillin formulations. The hydroxylamine method yielded slightly higher assay results than the microbiological method for severely degraded formulations.
Spectrophotometric Difference Method for Determination of Capsaicin
Authors: Dicecco Joseph J 
Published: February 2020

Abstract
Capsaicin is extracted from capsicum spice with acetone. The extract is cleaned up on an activated alumina column and assayed by using a spectrophotometric difference method (SDM). The coefficient of variation of replicate samples for 2 pungency levels was 0.36%. The correlation coefficient between the organoleptic assay and SDM was 0.95.
Criteria of Purity for Zearalenone Standards
Authors: Pathre Sadanand V , Mirocha Chester J , Fenton Stuart W 
Published: February 2020

Abstract
cis-Zearalenone was identified as one of the impurities in commercial zearalenone used as a reference standard. Zearalenone purified chromatographically gave molar absorptivities of 29,512±376, 13,225±15, and 6,162±61 at the absorption maxima of 236, 274, and 316 nm, respectively, in methanol. The precision in the ratio of absorbances for the major spectral peaks for purified zearalenone preparations provided a useful criterion of purity for zearalenone. A comparison of the GLC measurements of various purified zearalenone preparations with the amount of zearalenone in each preparation as determined by absorbance measurements demonstrated the validity of using absorbance measurements for zearalenone quantitation. Results from a collaborative study demonstrated that the concentration of solutions of zearalenone standards can be determined by UV absorbance measurements.
Analytical Reference Materials. I. Preparation and Purification of Photomirex
Authors: Chau Alfred S Y , Thomson Rod 
Published: February 2020

Abstract
The preparation and purification of photomirex (1,2,3,4,5,5,6,7,9,10,10 - undecachloropentacyclo [5.3.0.02,6.03,9.04,8]decane) as an analytical reference standard is detailed. A previous synthetic procedure was modified and improved to reduce hazards and to increase yield. Briefly, Mirex is reduced by triphenylphosphine in the presence of propionic acid, and purified by alumina column chromatography to obtain 60-70% yield of the desired compound.
Switching Valve Designed For High Pressure Liquid Chromatographic Fraction Collection
Authors: Landen William O 
Published: February 2020

Abstract
The use of a collection valve specifically designed for high pressure liquid chromatography is described. Application of the valve to high pressure gel permeation chromatographic (GPC) separation of oil from the vitamin A active fraction of margarine resulted in efficient oil removal after one pass through 2 μStyragel (100A) columns connected in series. Using the normal collection mode of the high pressure liquid chromatograph, 2 passes through the GPC columns were required to adequately resolve the fractions.
Thin Layer Chromatographic Method for Analysis and Chemical Confirmation of Sterigmatocystin in Cheese
Authors: Van Egmond Hans P , Paulsch Walter E , Deijll Ellen , Schuller Pieter L 
Published: February 2020

Abstract
A semi-quantitative method is described for the analysis of sterigmatocystin in cheese. The method is based on extraction of cheese with MeOH-4% KC1 (9+1), followed by Florisil and polyamide column cleanup and 2-dimensionaI thin layer chromatography (TLC). Visualization of sterigmatocystin on the TLC plates is enhanced by an ALCL3 spray reagent. The identity of sterigmatocystin is confirmed by a 2-dimensional TLC test based on reaction with trifluoroacetic acid (TFA) on the plate after first development. The reaction product formed is visualized by spraying with ALCL3. The method allows detection and confirmation of sterigmatocystin in cheese at concentrations as low as 5 μg/kg. The method has been applied to cheese samples ripening in warehouses and naturally molded with Aspergillus versicolor
Gas-Liquid Chromatographic Determination of Sodium Fluoroacetate (Compound 1080)
Authors: Okuno Iwao , Meeker Dennis L 
Published: February 2020

Abstract
An analytical method is described for the determination of Compound 1080 (sodium fluoroacetate) residues in 1–10 g tissue. Sample extracts of tissues are cleaned up with silica gel, and Compound 1080 (as fluoroacetic acid) is separated by a micro-distillation procedure. The fluoroacetic acid in the distillate is derivatized with pentafluorobenzyl bromide to form pentafluorobenzyl fluoroacetate which is measured by electron capture gas-liquid chromatography. Recoveries of sodium fluoroacetate from fortified tissue samples averaged about 25%. Despite the limited recoveries, results were quite reproducible, and levels as low at 2 ppm were determined in fortified 1 g samples, and 0.2 ppm in 10 g samples. The method is relatively simple and has been used routinely in our laboratory for the analysis of various types of samples such as grain, and tissues from birds, rodents, and larger animals.
Some Factors Affecting Assay Variability in the Determination of Chlortetracydine in Premix Feeds
Authors: Ragheb Hussein S 
Published: February 2020

Abstract
There are many sources of error in the microbiological determination of high levels of chlortetracycline in premix. Among the critical factors that can be controlled by the analyst are careful weighing of the reference standard and careful dosing of cylinders. A spectrophotometric approach and automatic filling of cylinders are suggested to ensure proper monitoring of these operations. Among factors that cannot be controlled by the analyst is the assay design. A 3-point design which is a modified version of the (3+3) design is considered, and its advantages are illustrated.
Ion Exchange Method for Rapid Determination of Alkalinity of Water-Soluble Tea Ash Containing High Levels of Manganese
Authors: Qureshi Saidul Z , Najib Fadhil M , Mohammed Fahmi A 
Published: February 2020

Abstract
An ion exchange method to determine the alkalinity of water-soluble tea ash containing high levels of manganese is described. A chromatographic column containing a strong cation exchange resin (20–50 mesh) in Na+ form, with a bed volume of 5 mL is used. The present ion exchange method is compared to pH titrations and also to the official AOAC methods (31.012, 31.015, 31.016). Results with the new method are accurate and precise.
Separation and Detection of Arsenical Pesticide Residues and Some of Their Metabolites by High Pressure Liquid Chromatography-Graphite Furnace Atomic Absorption Spectrometry
Authors: Woolson Edwin A , Aharonson Nadav 
Published: February 2020

Abstract
A method was developed for the separation and quantitative determination of arsenite, methanearsonic acid (MAA), dimethylarsinic acid (cacodylic acid or CA), and arsenate by high pressure liquid chromatography (HPLC) coupled to a graphite furnace atomic absorption (GFAA) detector. The compounds are separated on a low capacity anion exchange column with gradient elution from 100+ water-methanol (80 + 20, v/v) to 100% 0.02M (NH4)2CO3-methanol (85 + IS, v/v) at 1.2 mL/min and a pressure of about 300 psi. The HPLC was coupled by an automatic sampling unit to the GFAA through an interface consisting of a Teflon flow-through sampling cup. Limit of detection for the arsenic compounds was about 5 ng As injected in aliquots of 20 μL (0.25 ppm As in solution). All 4 arsenical compounds gave similar calibration curves, which were linear from 0.1 to 2.0 ng for single atomizations in the GFAA and from 5 to 200 ng when multiple, sequential atomizations of HPLC eluant were used to quantitate HPLC peaks. Quenching by soil extracts as well as aqueous HPLC solvents was minimal.
Colorimetric Determination of Methyl Parathion and Oxygen Analog
Authors: Nanda Kumar Nanguneri V , Ramasundari Mattipalli 
Published: February 2020

Abstract
A simple, sensitive, and rapid colorimetric method is described (or determining methyl parathion (0,0-dimethyl-O-ρ-nitrophenyl phosphorothioate) and methyl paraoxon (O,O-dimethyl-O-ρ-nitrophenyl phosphate), using ρ-nitrobenzene diazonium fluoroborate as the chromogenic salt. This colorimetric method is more sensitive than are other colorimetric methods based on nonenzymatic reactions. Pig liver acetone powder cholinesterase was found to be sensitive to methyl parathion. Inhibition can be detected at picogram levels, and 50–80 ng methyl paraoxon and 1–9 μg methyl parathion can be estimated.
High Performance Liquid Chromatographic Determination of Carbaryl Insecticide in Formulations
Authors: Mcdermott William H 
Published: February 2020

Abstract
A high performance liquid chromatographic method for carbaryl in formulations has been developed and used to assay 3 formulations in a 10-day repeatability study. The method uses a cyano modified silica gel column packing and a mobile phase of heptane-methylene chloride-isopropanol-methanol (60+35+4.8+0.2). The coefficients of variation for 2 wettable powders and one aqueous flowable formulation were 0.61, 0.62, and 0.75%, respectively. It is recommended that a collaborative study be conducted on this method.
Enhanced Detectability and Chromatography of Some Amines by High Pressure Liquid Chromatography
Authors: Noggle F Taylor 
Published: February 2020

Abstract
The high pressure liquid chromatographic properties of 13 phenylisothiocyanate derivatives of primary and secondary amines were examined with ultraviolet detection at 254 nm. Urine extracts of subjects who were taking ephedrine, phenylpropanolamine, and phentermine were also examined. The method described improves the chromatographic properties of the amines and also enhances their detectability.
Performance Specifications for Measuring Milkfat by Turbidimetric Means
Authors: Shipe W Frank , Senyk Gary F 
Published: February 2020

Abstract
Precision between duplicates of ≤0.03% for 0–5% and ≤0.04% for 5–8% fat is recommended regardless of type of milk. Maximum mean differences of ≤0.04% and standard deviations of difference of 0.10% for individual cow milk and 0.06% for bulk milks between instrumental values and standard chemical reference methods are specified. These recommendations are based on 95% confidence limits for 20 samples analyzed in triplicate. Sections 16.063–16.068 are revised to apply to all turbidimetric instruments regardless of model or manufacturer. A precaution section is included in the specifications to assure accurate instrumental performance. The specifications have been adopted as official first action.
Total Nitrogen Analysis of Soil and Plant Tissues
Authors: Nelson Darrell W , Sommers Lee E 
Published: February 2020

Abstract
Progress of the Dumas and Kjeldahl procedures over the past century is reviewed. Many recent papers claim that various modifications of the standard Kjeldahl method enhance accuracy, precision, or speed, and reduce cost of analysis. Furthermore, several authors advocate use of Pyrex tubes heated in an aluminum block for digestion instead of traditional Kjeldahl flasks. A review of current semimicro-Kjeldahl methodology suggests that proceeding under the following conditions gives satisfactory results: sample size, 50–200 mg for plant material, 100–500 mg for soil; digestion acid, concentrated H2SO4; sample size ratio (mL/g) of 16:1 for soils and 22:1 for plant materials; digestion salt, minimum 0.33 g K2SO4 added/mL H2SO4; catalysts, add CuSO4 5H2O at rate of 10% (w/w) of K2SO4 added, HgO at 5% (w/w) of K2SO4, or add Se to K2SO4–CuSO4 5H2O mixtures at rate of 1% (w/w) K2SO4; digestion time, 1 and 3 h past clearing for plant materials and soils, respectively; pretreatments, use salicylic acid or reduced iron to recover nitrate from sample. Use of Pyrex tubes heated in an aluminum block appears suitable for digestions. Our results indicate that the 2 commercial tube digestion systems tested produce satisfactory recovery of total N from soils and plant materials. Ammonium in Kjeldahl digests may be quantitatively determined by distillationtitration, ammonia electrode, or colorimetric techniques.