bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microchemical Determination of Sulfur by Oxygen Flask Combustion
Authors: Scroggins Laverne H 
Published: February 2020

Abstract
A collaborative study was conducted on the use of oxygen flask combustion in the microdetermination of sulfur. Eighteen collaborators performed duplicate analyses on 5 samples. In conjunction with the oxygen flask combustion, collaborators used gravimetric, colorimetric, and a variety of titrimetric procedures. All those employing gravimetric analysis used BaCl2 to precipitate BaSO4; the one analyst who employed the colorimetric technique used a recorded transmission at 530 nm with Ba(ClO4)2 and a Thorin-methylene blue indicator. Several indicators were used in the titrimetric procedures: sulfanazo III, dimethylsulfanazo III, Thorin-methylene blue, carboxyarsenazo-methylene blue, Thorin, and tetrahydroxyquinone. The differences in the precision and accuracy of the various methods were small except in the presence of potassium or phosphate ions. In the presence of these ions, dimethylsulfanazo III gave better results than any other indicator. It is recommended that the study be continued.
Nitrosopyrrolidine in Cooked Bacon
Authors: Fazio Thomas , White Richard H , Dusold Laurence R , Howard John W 
Published: February 2020

Abstract
N-Nitrosopyrrolidine has been found in cooked bacon but not in the raw bacon. Levels isolated from 8 commercial brands ranged from 10 to 108 ppb μg/kg). The identity of this nitrosamine has been confirmed by mass spectrometry.
Measurement of Egg Content of Noodles by Multiple Radial Immunodiffusion Analysis of Egg Proteins with Albumen-Specific Antiserum
Authors: Cantagalli Piero , Tassi-Micco Claudia 
Published: February 2020

Abstract
Extracts of egg noodles are prepared in 0.15M NaCl and analyzed by multiple radial immunodiffusion, using a commercially available albumen antiserum. Measurement of the area of the precipitation ring allows the quantitative evaluation of the egg content of noodles. Electrophoresis in polyacrylamide gel is used to identify the albumen proteins.
Electron Microscopy and X-Ray Microanalysis in Forensic Science
Authors: Brown John L , Johnson James W 
Published: February 2020

Abstract
The optical microscope has long been an important tool in forensic analysis for the comparison of firearms markings and the examination and identification of other minute bits of evidence. The electron microscope permits the examination of even smaller details and offers analytical capabilities unique to the type of instrument used. The transmission electron microscope can be used to identify very small amounts of crystalline materials through the process of electron diffraction. The scanning electron microscope can frequently supersede the optical microscope because of its superior depth of focus and range of magnification. When it is equipped with an energy dispersive X-ray analyzer, most of the chemical elements in a sample can be determined. Applications of these instruments have provided some interesting and instructive results in forensic analysis.
Quantitative Perchlorination of Polychlorinated Biphenyls as a Method for Confirmatory Residue Measurement and Identification
Authors: Armour Judith A 
Published: February 2020

Abstract
The perchlorination procedure for derivatization of PCBs described by Berg, Diosady, and Rees has been modified to achieve a micro-scale quantitative conversion (greater than 90%) of commercial PCB preparations (Aroclors) to decachlorobiphenyl. Cleaned up sample extracts containing PCB residues (1–20 μg) are allowed to react with antimony pentachloride in the presence of chloroform to form decachlorobiphenyl. This procedure converts a multicomponent mixture to a single derivative detectable by electron capture GLC, thus providing an easy method for quantitating and identifying PCB residues and at the same time increasing the sensitivity of detection. The usefulness of the perchlorination procedure is demonstrated by comparing results for environmentally contaminated samples quantitated by 2 methods: by measuring the total area of the electron capture response for the residue against the Aroclor it most closely resembles, and by measuring the single peak of the decachlorobiphenyl derivative and expressing the results in terms of the particular Aroclor.
Automated Method for the Determination of Direct Available P2O5 in Fertilizers
Authors: Hambleton Larry G 
Published: February 2020

Abstract
An automated photometric method for the analysis of direct available P2O5 in fertilizers has been developed. The method utilizes basic AutoAnalyzer equipment along with a heating bath to destroy ammonium citrate and coloring matter and also to hydrolyze non-orthophosphates. The 0.15 and 0.35 mg P2O5/ml ranges are expanded to read 10 and 90% T, respectively, with a sampling rate of 30 analyses/ hr. Experiments were conducted to show the effect of acid and ammonium citrate concentrations on color development. The normality of acid needed to completely hydrolyze the phosphorus in non-orthophosphate samples was also determined. Results for samples of urea-ammonium polyphosphate, sodium pyrophosphate, sodium metaphosphate, and ferric pyrophosphate analyzed by the automated method are reported and compared to results on the same samples analyzed by the official final action gravimetric quinolinium molybdophosphate method, 2.023–2.025; good agreement was shown between the methods. Six replicate determinations on 5 mixed fertilizer samples and a KH2PO4 primary standard by each method were in close agreement. The accuracy of the automated method was confirmed by analyzing 312 routine fertilizer samples by both the automated method and the gravimetric method; results did not show a significant difference when compared by Students’ l-test at the 5% level.
Gas-Liquid Chromatographic Determination of Erbon in Herbicide Formulations
Authors: Hanks Alan R , Engdahl Barbara S , Colvin Billy M 
Published: February 2020

Abstract
A simple and rapid gas-liquid chromatographic method, using flame ionization detection and a column packed with 5% silicone UCW 98 on Chromosorb W (HP), is described. Herbicide formulations containing Erbon are dissolved in chloroform, and Kepone is added as an internal standard. The sample solutions are injected directly into a gas chromatograph, and peak height ratios are used for quantitation. Using commercial herbicide formulations as test material, this procedure compares well with the more commonly employed titrimetric and total chloride procedures. As presented, this gas chromatographic technique has not been extended to include an estimation of the related compounds in technical Erbon. However, quantitation of these related compounds by this procedure is not precluded. This procedure does provide a method for more directly determining the compound of primary interest in Erbon formulations.
Gas-Liquid Chromatographic Determination of Chlorpyriphos in Dursban Insecticide Formulations
Authors: Hanks Alan R , Engdahl Barbara S , Colvin Billy M 
Published: February 2020

Abstract
A simple and rapid gas-liquid chromatographic method, using flame ionization detection and a column packed with OV-17/QF-1 on Gas-Chrom Q, is described. Chlorpyriphos is extracted from the formulation with chloroform, and dieldrin is added as an internal standard. The sample extract is injected into a gas chromatograph, and peak height ratios are used for quantitative measurement. Applicacation of the method to commercial samples gives good precision. The gas chromatographic procedure is far superior to the total chloride method for the determination of chlorpyriphos and yields values in close agreement to those obtained by infrared and colorimetric methods.
Collaborative Study of the Stability of Aflatoxin M1 Standards
Authors: Purchase Iain F H , Altenkirk Brian 
Published: February 2020

Abstract
Nine laboratories took part in an international collaborative study of the stability of aflatoxin M1 standards. The study confirmed the suitability of ultraviolet absorption spectrophotometry, as described for standardization of aflatoxin B and G solutions, for standardization of aflatoxin M1 solutions. Standards of aflatoxin M1 dissolved in chloroform were superior to those dissolved in benzene-acetonitrile (98 + 2), and no measurable decrease in concentration was observed after 4 months of storage at −10°C. The intensity of fluorescence of aflatoxins B1 and M1 after separation on silica gel thin layer plates was found to be nearly the same when measured visually or by densitometry.
Collaborative Study of a Colorimetric Method for Determining Arsenic Residues in Red Meat and Poultry
Authors: Buttrill W Hearon 
Published: February 2020

Abstract
A colorimetric method is described for the determination of arsenic residues, which uses the molybdenum blue complex for a Spectrophotometric readout. The method was studied by 9 collaborators, each analyzing 6 groups of 4 samples. Average recoveries for 0.28–2.41 ppm arsenic were 87.6–109.3%; standard deviations ranged from 0.037 to 0.225. The method has been adopted as official first action.
Improved Biological Assay Procedure for Oleandomycin in Animal Feeds
Authors: Mayerhofer Hans J 
Published: February 2020

Abstract
The AOAC method was modified by using a pH 8.0 phosphate bicarbonate buffer standard curve, improving assay simplicity, reliability, and precision while decreasing the assay time. Six blank feeds to which oleandomycin activity was added at levels of 2 and 5 g/ton (Exp. A) as well as commercially medicated feeds of the same formulation as the blank feeds (Exp. B) were assayed by both methods. Average recovery in Exp. A was 102% of theory by the modified method, against 89% by the AOAC method. For Exp. B, the recovery was 93% of label claim versus 82.5%, respectively. The AOAC method produced low biased results (12.5%), since 10% of the residual activity remained in the heated feed extract. The additive effect was further substantiated by “respiking” feed samples after they were inactivated. Samples assayed by the modified method tested 7.22% higher as compared with the medicated feeds assayed directly. Poultry feeds containing 2.0 g oleandomycin/ton were tested by the modified method with recoveries of 101.0% of theory.
Propanil Hydrolysis : Inhibition in Rice Plants by Diazinon and Carbaryl Translocated from the Soil
Authors: El-Refai Ali , Mowafy M M 
Published: February 2020

Abstract
Greenhouse and laboratory experiments were designed to determine the effect of soil-applied carbaryl and diazinon on the phytotoxicity of foliage-sprayed propanil. A time-course study of the activity of propanil-hydrolyzing enzyme in rice indicated a slow increase in the rate of hydrolysis during early stages of growth, followed by a sharp increase for extracts of the 7-week-old samples. The rate of hydrolysis reached its maximum at harvest time (approximately 17 weeks). The enzyme activity of barnyard grass was not detected at different growth stages. The enzyme was inhibited by diazinon and strongly inhibited by carbaryl absorbed and translocated from the soil over a wide range of growth stages of rice. Rice plants were more susceptible at early stages of growth and this confirms the significant correlation between growth stage and enzyme activities. Analyses of tissue extracts by paper chromatography and an enzyme inhibition method agreed closely at all intervals. It seems probable that the inhibition rate of enzyme is related to the persistence and rate of translocation of carbaryl.
Determination of Sodium Salt of 1-(p-Toluidino)-4-(o-sulfo-p-toluidino) Anthraquinone and the Sodium Salt of 1-Hydroxy-4-(o-sulfo-p-toluidino) Anthraquinone in D&C Green No. 5
Authors: Stein Charles , Cox Elizabeth Ann 
Published: February 2020

Abstract
A thin layer chromatographic procedure is presented which separates 1-(p-toluidino)-4-(o-sulfo-p-toluidino) anthraquinone (sodium salt) and 1-hydroxy-4-(o-sulfo-p-toluidino) anthraquinone (sodium salt) from D&C Green No. 5. The separated colors are extracted from the adsorbent and determined spectrophotometrically. Recoveries of the former, added at 0.4–5.0% levels, ranged from 88 to 100%. Recoveries of the latter, added at 0.4–5.0% levels, ranged from 87 to 124%. Commercial samples of D&C Green No. 5 analyzed by this procedure contained 0.1–3.7% of the former and 0.1 to 0.5% of the latter.
Collaborative Study of the Microscopical Characterization of Glass Fragments
Authors: Mccrone Walter C 
Published: February 2020

Abstract
The Emmons double variation method for the microscopical characterization of glass fragments was collaboratively studied. In this technique, identification is based on the measurement of the temperature and wavelength of refractive indices matches for glass fragments mounted in a known refractive index liquid. Seven collaborators and 3 intralaboratory analysts examined an unknown glass sample at 486, 589, and 656 nm. The respective wavelength errors (× l0−5) were 52, 26, and 20. The overall laboratory average error over all the wavelengths was 33 × 10−5. The method has been adopted as interim official first action.
Determination of Lead in Evaporated Milk by Atomic Absorption Spectrophotometry and Anodic Stripping Voltammetry: Collaborative Study
Authors: Fiorino John A , Moffitt Robert A , Woodson Albert L , Gajan Raymond J , Huskey Glen E , Scholz Robert G 
Published: February 2020

Abstract
A method for the determination of lead in evaporated milk was successfully collaborated by 11 laboratories. Five laboratories used both atomic absorption spectrophotometry (AAS) and anodic stripping voltammetry (ASV) for the determination, 5 used only the atomic absorption method, and 1 used only the polarographic method. Each collaborator received 12 samples, 2 at each of the 5 different levels (0.06–0.95 ppm) and 2 practice samples with a known lead content. Both AAS and ASV were equally suitable for the determination of lead in the concentration range studied. The pooled variation between duplicate determinations was 0.0010 and 0.0016 for the AAS and ASV methods, respectively. For the AAS determinations the coefficients of variation (random error components) decreased from 43% at the lowest Pb level to 4% at the highest level. Although the ASV results did not show the same regularity of decreasing coefficients of variation with increasing Pb level, the coefficients of variation were acceptable: 28% at the 0.06 ppm level and 6% at the 0.22 ppm level. The AAS method has been adopted as official first action and the ASV method as interim official first action.
Determination of Sucrose Diacetate Hexaisobutyrate in Soft Drinks by Gas-Liquid Chromatographic Analysis of Isobutyric and Acetic Acid Components as Decyl Esters
Authors: Conacher Henry B S , Chadha Rajinder K , Iyengar Jagannath R 
Published: February 2020

Abstract
A procedure is presented for the quantitative estimation of sucrose diacetate hexaisobutyrate in soft drinks based on quantitative determination of the acetic and isobutyric acid components. The method involves an acidcatalyzed transesterification of the sucrose esters with sulfuric acid in decanol followed by GLC analysis of the resulting decyl acetate and isobutyrate, using hexanoic acid as internal standard. Recoveries of sucrose diacetate hexaisobutyrate from drinks fortified with this compound ranged between 92.8 and 97.8% in calculations based on acetic acid content and between 97.1 and 99.3% in those based on isobutyric acid. The analysis of several commercialjdrinks gave sucrose ester contents ranging from 11.5 to 14.2 mg/10 fluid oz.
Spectrophotometric Determination of Dehydroacetic Acid in Fruits and Vegetables
Authors: Piwowar Theodore S 
Published: February 2020

Abstract
A method for the determination of the preservative dehydroacetic acid (DHA) in strawberries, bananas, and zucchini squash is described. The samples are blended and extracted with chloroform. The chloroform extract is cleaned up on a preparatory silicic acid-glass fiber sheet. The DHA is determined by its ultraviolet absorbance at 307 nm. The average recovery of DHA added at levels of 5 to 80 ppm was 100.2 ±4.8% (15 analyses). The method is sensitive to 2 ppm DHA.
Instrumental Parameters for Determination of Mercury by Flameless Atomic Absorption Spectrophotometry
Authors: Hoggins Frank E , Brooks Robert R 
Published: February 2020

Abstract
Studies have been made on the instrumental parameters affecting the performance of the solution-reduction and the thermal-volatilization techniques of flameless atomic absorption for mercury. Optimum conditions established for the solution-reduction technique were: gas flow 5 L/min, stirring time 100 sec, and stirring rate at least 1250 rpm. Optimum conditions for the thermal-volatilization technique were: flow rate 1.5 L/min, heating time 20 sec. The 2 techniques are compared.
Collaborative Study of the Rapid Determination of Moisture and Fat in the Same Sample of Meat or Meat Product
Authors: Pettinati Julio D , Cohen Edward H 
Published: February 2020

Abstract
A method utilizing azeotropic distillation for determining moisture and fat in the same sample of ground beef, frankfurters, or pork sausage was collaboratively studied. The apparent moisture content of these products, determined by measuring the volume of condensate after 30 min distillation with cumene, m-xylene, or ethylbenzene, was 1 % lower than that determined by method 24.003(a). The fat content was determined by weighing the residue from an aliquot of the extract taken after 30 min (ground beef and frankfurters) or 45 min (pork) distillation. The fat content of ground beef and frankfurters, determined by using all 3 solvents, agreed with results obtained by method 24.005(a); results for pork samples were about 1% low. Significant positive correlation (r = 0.99) was obtained for both moisture and fat data with results from the AOAC methods. Statistical evaluation of the collaborative results for the 3 meat products, using the 3 solvents, led to expected standard deviations, se, of ±0.94% moisture and ±1.03% fat. Azeotropic distillation with cumene, m-xylene, or ethylbenzene is useful as a rapid screening procedure for determining moisture and fat in meats prior to processing or in finished products where rapid analysis is more important than maximum accuracy and precision.
Improvements and Modification of the Gas-Liquid Chromatographic Determination of Vitamin D2 in Multiple Vitamin Tablets and Raw Materials
Authors: Edlund David O , Filippini Florido A 
Published: February 2020

Abstract
A gas-liquid chromatographic procedure used to determine vitamin D2 in multiple vitamin tablets and raw materials has been improved by the use of a Dexsil 300 GC column packing. Sample preparation procedures have been modified. The improved procedure has been statistically evaluated and found to be both accurate and precise.
Optical Rotation Assay for Determination of Sorbitol in the Presence of Mannitol and Sugars
Authors: Dokladalova Jarmila , Upton Ronald P 
Published: February 2020

Abstract
The optical rotation of molybdate complexes of mannitol and sorbitol are measured in low acidity medium and thus only the mannitol content is determined. In high acidity medium both hexitols exhibit concentration-dependent optical rotation. Mannitol content is corrected for and the concentration of sorbitol is calculated. The effect of sugars can be corrected for by measuring optical rotation in the absence of molybdate. Reproducibility of the sorbitol determination is characterized by a standard deviation of 0.328%.
Colorimetric Determination of Saccharin in Foods
Authors: Fernandez-Flores Enrique , Johnson Arthur Russell , Leber Barry , Larry Damon , Lerner Sylvia 
Published: February 2020

Abstract
Samples of 6 types of foods containing saccharin were subjected to a cleanup procedure, using lead acetate or alcohol precipitation. Saccharin was extracted with a combination of solvents and the extracts were treated with phenol and sulfuric acid and heated to form colored phenolsulfonphthalein derivatives. The color was measured spectrophotometrically at 558 nm. The method was applied to soft drinks, fruit juices, food sweetener tablets, concentrated liquid sweeteners, jellies, preserves, low calorie high protein powders, granulates, and liquids, and chocolate bars. Recoveries ranged from about 90.3 to 121.0% in spiked samples. Satisfactory recovery was obtained for levels as low as 5 mg/100 g sample (0.005%).
Automated Determination of Reducing Sugars, Total Sugars, and Starch in Plant Tissue from One Weighed Sample
Authors: Powell Gaines T 
Published: February 2020

Abstract
An analytical scheme for the simultaneous quantitative analysis of reducing sugars, total sugars, and starch in plants from a single sample is presented. Sugars are removed by an acidic methanol extraction and starch is extracted by shortening the AOAC method. Nonreducing sugars and starch are hydrolyzed to reducing sugars and determined by automated colorimetry, utilizing AutoAnalyzer modules. This colorimetric system employs the potassium ferricyanide-potassium ferro-cyanide oxidation-reduction reaction. The yellow color of ferricyanide, when heated with reducing sugars, diminishes in proportion to the quantity of sugar present, due to the production of colorless ferrocyanide. The sampling rate is 30 samples/hr. Results compare well with the much longer AOAC methods for each respective component. The method is rapid and relatively simple, and gives accurate, reproducible results. The amount of total carbohydrates is obtained by adding the total sugar and starch values.
Method for the Determination of Aflatoxin M1 in Fluid Milk and Milk Products
Authors: Pons Walter A , Cucullu Alva F , Lee Louise S 
Published: February 2020

Abstract
The method described utilizes acetone-water (77+23) for extraction of M1 from milk and milk products in a 3 min blender extraction. Phospholipids and soluble proteins in the primary extract are removed by treatment with lead acetate, and residual neutral lipids in the treated extract are removed by partition into hexane. Aflatoxin M1 is partitioned into chloroform, which is then washed with salt solution, and the chloroform is evaporated. The residue is dissolved in chloroform, and M1 is resolved on silica gel-coated plates developed in chloroform-acetone-2-propanol (850+100+50). This basic procedure is applicable to fluid milk and reconstituted freeze-dried milk powder at levels as low as 0.1 μg M1/L. Extracts of nonfat dry milk, evaporated and condensed milk, and cheeses, which require further cleanup before TLC, are purified on a cellulose-aqueous methanol partition column to allow reliable determination of M1 at levels as low as 0.2 Mg/L or kg. Average recovery of M1 added to fluid milk at levels of 0.1–1.0 μg/L was 106% without the use of the cleanup column and 90% when the column was used to purify the extracts. Average recovery of M1 added to other milk products at a level of 0.2 Mg/L or kg was 88%. The precision of the method (coefficient of variation) was estimated to be ±16% at 0.2 Mg/L in fluid milk, and ±4% at a 34 Mg/kg level in contaminated freeze-dried milk.