bluuebunny/crossref_metadata_2025 huggingface dataset:
Dry Ashing Technique for the Determination of Arsenic in Marine Fish
Authors: Leblanc Patrick J , Jackson Adrian L
Published: February 2020

A dry ashing procedure, followed by the silver diethyldithiocarbamate colorimetric determination of arsenic in marine fish, is presented. The sample is first homogenized and a portion is pre-ashed with magnesium nitrate, using infrared heat, followed by ashing in a 500°C muffle furnace. The residue is dissolved in HCl and the arsenic is reduced by means of zinc and HCl to arsine, which is complexed with AgDDC and determined colorimetrically at 535 nm. At temperatures of 460°C and above, efficient ashing was obtained. The effect of various volumes of ashing aid (50% magnesium nitrate) was also studied. Maximum recovery and precision were obtained when a minimum of 8 ml 50% magnesium nitrate was used. Standard recoveries of inorganic arsenic added to NBS orchard leaves and a sample of dry marine fish tissue gave values of 91–98%. Analyses of a number of standard NBS orchard leaves and marine fish As-1 and As-2 gave coefficients of variation of 7.0, 6.0, and 8.1%, respectively. Results from dry ashing and wet digestion of a number of species of marine fish were not comparable. Levels of arsenic found in different species of marine fish ranged from <0.4 to 27.0 μg As/g wet weight. Crabs were found to contain elevated amounts of arsenic.
Collaborative Study of the Foss Milko-Tester Method for Measuring Fat in Milk
Authors: Shipe W Frank , Senyk G F
Published: February 2020

In a third collaborative study, the Milkotester was compared with the Babcock method in 9 laboratories. In addition, 3 laboratories analyzed the samples by an ether extraction method. The standard deviations for these methods were +0.018, +0.032, and +0.044%, respectively. These deviations are based on triplicate determinations on 5 samples by each of the laboratories. The average values for all samples were 3.99, 3.96, and 3.88% for the Milko-tester, Babcock, and ether extraction methods, respectively. The standard deviation of differences between the Milko-tester and Babcock for all 9 laboratories was +0.077%.
Infrared Analysis of Carbaryl Insecticide: Modification of the Extraction Procedure to Accommodate Liquid Suspension Formulations
Authors: McDermott William H
Published: February 2020

The extraction procedure for the official first action infrared analysis for carbaryl in formulations, 6.206–6.208, has been modified by the addition of anhydrous granular sodium sulfate to make the method applicable to liquid suspension formulations of carbaryl. A limited collaborative study of the modified method yielded a standard deviation of ±1% at the 40% level and a coefficient of variation of ±2%. The modification has been adopted as official first action.
Preparation of 14C-Labeled Aflatoxin B1
Authors: Schoenhard Grant L , Sinnhuber Russell O , Lee Donald J
Published: February 2020

A successful method to obtain 14C-labeled aflatoxin B1 from Aspergillus parasiticus ATCC 15517 was developed. The nitrogen-free resting culture contained mycelia from a 72 hr primary culture, 0.02M glucose, 0.005M (1 mCi/mmole) acetate-1-14C, salts, and trace metals. It was incubated 12 hr at 30°C. Aflatoxin B1-14C was isolated from chloroform extracts of the resting culture by column chromatography on silica gel H eluted under pressure with a continuous gradient of chloroform to chloroform-methanol (98+2). The ultraviolet spectrum of the 14C-labeled aflatoxin was examined. The ratios of the absorbances at 220/265 and 362/265 nm compared to established values and a reference standard were used as criteria of chemical purity. Label integrity was verified by chromatography, hydrogenation to the tetrahydrodeoxoaflatoxin B1, and conversion to the hemiacetal and the epimeric acetates. After purification, 1.37 mg 14C-labeled aflatoxin B1 of specific activity 744 μCi/mmole was obtained from 2 mCi acetate-1-14C of specific activity 1 mCi/mmole.
Semiautomated Colorimetric Determination of Methenamine and Methenamine Mandelate in Tablets
Authors: Dow Matthew L
Published: February 2020

A semiautomated chromotropic acid colorimetric procedure was collaboratively studied by 6 laboratories, both as a composite assay and as an individual tablet assay method. Results agreed well with the USP and NF methods. The coefficients of variation ranged from 0.54 to 2.48%. The method has been adopted as official first action for the analysis of coated and uncoated tablets of methenamine mandelate, methenamine, and methenamine with sodium biphosphate.
Separation of dl-2-(3-Phenoxyphenyl) propionic Acid (Fenoprofen) From Its Intermediates by Thin Layer Chromatography
Authors: Bishara Rafik H
Published: February 2020

Fenoprofen and its synthetic intermediates are resolved on silica gel F254 TLC plates developed with chloroform-acetic acid (98+2). The interrelationship between the chemical constitution and the Rf values is discussed. The lower limit of detecting the intermediates in Fenoprofen raw material is 1%.
Minicomputer—Automatic Analysis System for Pharmaceuticals
Authors: Alber Larry L , Overton Mack W , Smith Donald E
Published: February 2020

Software has been developed for reduction of automatic analyzer data both for on-line and off-line modes, using a PDP-12 minicomputer with 8K core memory, magnetic tape and disk storage, a multiplexer and 16 channel 10-bit analog-to-digital converter, and a cathode ray tube. The on-line system performs data-logging onto magnetic tape of 16 instruments asynchronously, displaying any 2 analog-to-digital conversion channels on the cathode ray tube in real-time. Spectrophotometers are interfaced to the computer, using economically constructed operational amplifier circuits. Data reduction is aided by a hardware floating-point processor, using an 8-point least-squares fitting algorithm to digitally smooth the data array and determine each peak maximum. Computer results of 3 different systems operating simultaneously are compared to values obtained manually. The off-line system was written using FOCAL-12 conversational language and will accept digital values by Teletype, peak detector paper punch, or TWX; the latter makes the program available to other laboratories through the Federal Telecommunications TWX System.
Determination of Propoxyphene and Aspirin in Combinations
Authors: Cunningham Catherine G , Barkan Susan
Published: February 2020

Propoxyphene is assayed by a partition chromatographic method in which it is eluted as the ion pair with CHCl3 from a sulfamic acid-Celite column and determined spectrophotometrically. Napsylate anion present in some formulations is retained on a NaHCO3-Celite trap column.
Collaborative Study of a Spectrophotometric Method for the Determination of Dienestrol in Pharmaceuticals
Authors: Graham Joseph H
Published: February 2020

A highly specific, sensitive, and rapid method for the determination of dienestrol was studied by 13 collaborators. Dienestrol is separated from excipient matter, degradation products, and other drugs present by column partition chromatography, converted to a substituted indene by acid-induced isomerization, and determined by ultraviolet spectrophotometry. Standard deviations obtained for the 4 samples used in the study, containing approximately 0.1 and 0.5 mg dienestrol, ranged from 1.81 to 3.04. The most critical step in the method is the use of suitable ether. This method has been adopted as official first action.
Collaborative Study of the Method for the Analysis of Trisulfapyrimidine Preparations by Thin Layer Chromatography
Authors: Brunner Charlotte A
Published: February 2020

The TLC method for trisulfapyrimidine preparations reported earlier has been collaboratively studied. Fifteen collaborators reported results for total trisulfapyrimidine as well as individual results for sulfadiazine, sulfamerazine, and sulfamethazine for 3 samples (commercial composite, commercial suspension, and simulated tablet mix). The coefficients of variance for the total sulfur content of the 3 samples were 1.65, 1.25, and 1.55. For the determination of the individual sulfur components, the coefficients of variance ranged from 0.76 to 1.66. The method has been adopted as official first action.
Uncombined Intermediates in FD&C Red No. 40
Authors: Marmion Daniel M
Published: February 2020

The results of a collaborative study are reported. Nine collaborators from industry and government analyzed 3 samples each. The intermediates were separated from FD&C Red No. 40 and from each other on a cellulose column, using 40 and 20% aqueous ammonium sulfate as eluants, and were quantitated by UV spectrometry. Cresidinesulfonic acid, Schaeffer’s salt, and 6,6′-oxybis(2-naphthalenesulfonic acid) were recovered at an average level of 99.7%. Between-laboratory standard deviations ranged from 0.007 to 0.072% when the intermediates were present at levels of 0.03 to 1.00%. The method has been adopted as official first action.
Oxytetracycline Residues in Milk Following Intramammary Infusion
Authors: Katz Stanley E , Fassbender Carol A , Hackett Arthur J , Mitchell Ralph G
Published: February 2020

An intramammary infusion of Oxytetracycline was used to study the potential of residues occurring in milk from a recommended usage program. Residues from the treated quarters persisted as long as 5.5 days. Residues in milk from the rear quarters disappeared in 3.5–4.5 days; residues in the milk from the front quarters persisted 5.0–5.5 days. In any case, residues persisted longer than an interval consistent with the recommended 4 day withdrawal period. Residues in the milk of the untreated quarters appeared to arise from transfer via the circulatory system and not from septal transfer.
Factors Relating to Completeness of Solvent Extraction of Dieldrin from Milk
Authors: Ang Catharina Y W , Dugan Leroy R
Published: February 2020

Milk containing added dieldrin was separated into 2 lipid fractions by differential solvent extraction. Fraction 1 was extracted with nonpolar hydrocarbon solvents and Fraction 2 with the same solvent system after mixing with sodium oxalate and ethanol. Three solvent systems were compared. Dieldrin concentrations in Fraction 1 of all 3 solvent systems were much higher than in Fraction 2 on a fat basis. Less than 50% of the dieldrin was recovered in Fraction 1, probably because of the low recovery of hydrocarbon solvents from fluid milk or factors that depressed the separation of solvents from milk. Factors possibly involved were the adsorption of solvents and pesticide to the hydrophobic groups of membrane proteins and/or serum proteins or the penetration of solvents and pesticide into the fat globules of milk.
Comparative Extraction of Chlorinated Hydrocarbon Insecticides from Soils 20 Years After Treatment
Authors: Nash Ralph G , Harris William G , Ensor Peter D , Woolson Edwin A
Published: February 2020

Three methods, shake, Soxhlet, and column, were compared for efficiency of extraction of certain chlorinated hydrocarbon insecticides from a Congaree sandy loam soil which had been treated 20 years earlier. Column extraction had a tendency to be less efficient than the other 2 methods, but statistically there were no differences in extraction efficiencies among the 3 methods for aldrin, dieldrin, heptachlor, chlordane, isodrin, endrin, toxaphene, or Dilan and their residue products. However, shake extraction was significantly more efficient for the BHC isomers than Soxhlet extraction and the latter was significantly more efficient than column extraction.
Calculation of Turbidimetric Microbiological Vitamin Assay Results, Using an APL/360 Computer Program
Authors: Brolund Gregory V , Haskins Ethelbert W , Hudson George A
Published: February 2020

An APL-360 computer program is described for the calculation of results from microbiological vitamin assays. The results are compared to manual calculations specified in official AOAC methods. This comparison shows the validity of the computer program for these calculations.
Modified Rapid Screening Method for Aflatoxin in Corn
Authors: Shannon Gail M , Stubblefield Robert D , Shotwell Odette L
Published: February 2020

A rapid screening method for detecting aflatoxin in cottonseed products was investigated to determine if it was applicable to corn. Other aflatoxin-extracting solvents and protein-precipitating agents were tried with white and yellow corn. When acetone-water (85+15) and a saturated solution of ammonium sulfate were substituted for acetonitrile-water (80+20) and lead acetate in the cottonseed method, fewer interferences and more compact fluorescent zones were observed on the developed minicolumns. The modified method for corn was applicable to samples containing 10 ppb or more aflatoxin.
Dry Ashing Method for the Determination of Total Arsenic in Animal Tissues: Collaborative Study
Authors: George Glenn M , Frahm Larry J , McDonnell J Patrick
Published: February 2020

The method described for the determination of total arsenic in animal tissue is sensitive to levels of 0.1 ppm. Tissue samples are dry-ashed in the presence of magnesium oxide and magnesium nitrate and the arsenic is determined colorimetrically with silver diethyldithiocarbamate. The arsenic content in the tissue is determined from standard curves prepared for each tissue, thereby correcting for losses during the ashing step. The average recovery for 8 collaborators was 98.8% for poultry tissue and 103.4% for swine tissue with an average overall coefficient of variation of 8.31% for the entire study. This method has been adopted as official first action.
Collaborative Study of Three Screening Methods for Aflatoxin in Corn
Authors: Shotwell Odette L , Stubblefield Robert D
Published: February 2020

The 3 rapid screening methods studied all involved chromatography of partially purified extracts on minicolumns. In one method acetonitrile-water is used to extract aflatoxin from corn and a lead acetate precipitation removes impurities from the extracts. The second method specifies acetone-water as the extracting solvent and ammonium sulfate as the precipitant. The third method is based on acetone-water as the extracting solvent and ferric gel as the precipitant. The most sensitive method was the ferric gel precipitation, which could detect 5 ppb aflatoxin, but it was very time-consuming. The most satisfactory method (timewise) used the ammonium sulfate and had a sensitivity of 10 ppb. This method also led to the best differentiation between levels of aflatoxin. These 2 methods have been adopted as official first action.
New Collaborative Study of a Zincon Ion Exchange Method for the Quantitative Determination of Zinc in Fertilizer
Authors: Pracht Louis E , Jones Clyde E
Published: February 2020

A collaborative study was performed with 8 Magruder samples to evaluate a new zincon colorimetric method, an alternative to 2.137. The previous zincon method was modified, but the basic principle remains: 0.5N HCl retains a stable Zn(II) chloro-complex ion on an anion exchange resin but not interfering cations; 0.005N HCl elutes the Zn(II) ion which is determined colorimetrically in the presence of the indicator, zincon. Overall estimate of precision, Sr = 0.033, is similar to Sr = 0.030 for atomic absorption. Sb values (0.074 at 0.05%, 0.035 at 0.25%, and 0.054 at 1%) compare favorably with atomic absorption Sb values (0.072 at 0.05%, 0.036 at 0.25%, and 0.063 at 1%). F- and t-test results at the 95% confidence level indicate systematic error by both methods but do not discern a difference in the true value each method can measure. Average single sample values agree better with Magruder grand averages than corresponding averages by atomic absorption. While applicable to samples containing 0.05% zinc and higher, the method is quite time consuming when samples are low in zinc and have high iron—zinc ratios. This method has been adopted as official first action.
Collaborative Study of the Determination of Water-Insoluble Nitrogen in Fertilizers
Authors: Katz Stanley E , Fassbender Carol A
Published: February 2020

Three procedures for water-insoluble nitrogen in fertilizers were collaboratively studied; the extraction method; the water-insoluble nitrogen method, 2.064; and the slow-release nitrogen method, 2.072. The extraction method and 2.064 gave comparable results for water-insoluble nitrogen, with similar degrees of repeatability. Method 2.072 yielded values which did not consistently agree with either the extraction method under study or 2.064. In addition, 2.072 yielded results with variances between laboratories that were unexpectedly high. The extraction method has been adopted as official first action. It is recommended that 2.064 remain official first action, and that 2.072 be repealed, first action.
Effects of Solvent Composition on the Partition of Barbiturates
Authors: Doyle Thomas D , Proctor Joseph B
Published: February 2020

The distribution of 5 common barbiturates between water and various mixed organic phases was studied in detail. It was shown that ether gave uniformly higher extraction constants than chloroform; dilution of these solvents with isooctane resulted in rapid, nonlinear decreases in extraction; these variations can be approximately described by an exponential equation. A uniform sequence of extractability was found, in decreasing order: secobarbital, pentobarbital, amobarbital, butabarbital, phenobarbital. Partition was independent of barbiturate concentration but varied with pH as expected by simple ionization considerations; these facts indicate that extraction of monomeric free barbiturate was the only important process. A large temperature effect was found for secobarbital. The results obtained are discussed in relation to the known partition chromatographic behavior of barbiturates.
Collaborative Study of an Atomic Absorption Method for the Determination of Lead and Cadmium Extracted from Glazed Ceramic Surfaces
Authors: Krinitz Benjamin , Franco Vincent
Published: February 2020

A method for the determination of lead extracted from glazed ceramic surfaces was adapted from the German standard procedure and extended to include extractable cadmium. Studies comparing a 0.5 hr exposure to 4% acetic acid at room temperature (22±2°C) with a 24 hr exposure under the same conditions indicated that the longer exposure gave higher, asymptotic values for extracted metal. In the collaborative study, 7 samples of the 24 hr leach solution containing lead, one of these also containing cadmium, were sent to 13 collaborators for analysis by atomic absorption. The results show that the method is precise and accurate. The average relative standard deviation for lead was 5.2%, and for cadmium, 3.9%, with average recoveries of 101% for both metals. The method has been adopted as official first action.
Microchemical Determination of Sulfur by Oxygen Flask Combustion
Authors: Scroggins Laverne H
Published: February 2020

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Collaborative Study of Two-Dimensional Thin Layer Chromatographic Analysis of Aflatoxin B1 in Peanut Butter Extracts, Using the Antidiagonal Spot Application Technique
Authors: Beljaars Paul R , Verhülsdonk Cornelius A H , Paulsch Walter E , LIEM DHIAM H
Published: February 2020

A collaborative study has been carried out among 20 laboratories in The Netherlands, representing governmental and industrial institutes, on the determination of aflatoxin B1 in peanut butter extracts. Blank peanut butter extracts prepared according to the proposed official Dutch method were spiked with aflatoxin B1, representing contamination levels of 0, 3, 6, and 12 μg B1/kg. Samples and standards were spotted on silica gel G TLC plates by the antidiagonal spot application technique described herein. Spotted plates were developed by 2-dimensional TLC with diethyl ether-methanol-water (94+4.5+1.5; lined tank) in the first direction and chloroform-acetone (90+10; unlined tank) in the second direction. Separated B1 spots from sample and standards developed in both directions were free from background interference. The quantity of aflatoxin B1 present in the sample was established by visual comparison of the fluorescent intensities of sample and standard B1 spots. For this procedure the variability of measurements within and between laboratories was statistically investigated: 80–90% of the complete results given by the participants were correct for the hlank and spiked extracts (contamination level of 12 μg B1/kg). For contamination levels of 3 and 6 μg B1/kg an approximate coefficient of variation of 35% was calculated for within- and between-laboratory results. Results obtained in this investigation were compared with those found by previous investigators who used the one-dimensional TLC technique. It is concluded that, with the antidiagonal procedure, small amounts of aflatoxin B1 (lowest level tested, 3 ppb) may be detected.
Determination of Isonicotinic Acid Hydrazide by Direct Bromimetric Titration
Authors: Urbanyi Tibor , Winchurch Robert
Published: February 2020

Isonicotinic acid hydrazide alone and in tablet formulations was determined by a bromimetric titration. This titration gave more accurate and reproducible results and was more rapid than the iodometric method. The end point of the titration was detected visually or electrometrically. Electrometric titrations were used only for formulations in which an ingredient obscured the visual end point detection because of its strong color. Oxidizable compounds such as carbohydrates, which are common excipients in formulations and which gave high assay results with the iodometric method, do not interfere. The proposed method can be employed for formulations without any time-consuming preparations.
Determination of Sulfaquinoxaline, Sulfathiazole, Sulfamerazine, and Sulfamethazine in Feed Concentrates or Premixes
Authors: Cieri Ugo R
Published: February 2020

Sulfaquinoxaline is determined by its UV absorbance at about 358 nm, where the other 3 sulfonamides do not absorb. Sulfathiazole, sulfamerazine, and sulfamethazine are determined by a quantitative TLC procedure, based on the separation of the compounds on silica gel plates; the spots are extracted and the centrifuged extracts are analyzed spectro-photometrically. A method of calculating the total sulfonamide content, independent of the individual components, is also introduced.
Formation of Pentafluorobenzyl Derivatives for the Identification and Quantitation of Acid and Phenol Pesticide Residues
Authors: Johnson Lauren G
Published: February 2020

A procedure is described for the preparation and electron capture GLC determination of pentafluorobenzyl ester and ether derivatives of 2,4-D, p,p′-DDA, 1-naphthol, p-nitrophenol, and sec.-amyl phenols. A column cleanup procedure quantitatively isolates the derivatives from excess reagents and other interferences. The method can be used as an aid in the confirmation of the identity of pesticide residues and for the quantitative determination of extracted residues.
Modified Procedure for Determining Mercury in Coal by Cold Vapor Atomic Absorption Spectrophotometry
Authors: Lo Fa-Chun , Bush Brian
Published: February 2020

The combustion procedure previously described for the determination of mercury in coal by cold vapor atomic absorption spectrophotometry has been modified to permit samples to be analyzed more rapidly and with better precision. A coefficient of 8.3% was obtained for the analysis of 7 samples containing 0.1 ppm mercury. In addition a greater variety of types and particle sizes of coal can be analyzed by the modified procedure.
Ultrasonic Solubilization Technique for Use in Coulometry
Authors: Ferren William P , Fortinash William M
Published: February 2020

An ultrasonic solubilization technique has been developed which is useful as a first step in the coulometric determination of the chloride content of crystalline organic compounds such as p-chlorobenzoic acid.
Column Chromatographic Cleanup and Gas-Liquid Chromatographic Determination of Hydroxybenzoic Esters in Food
Authors: Daenens Paul , Laruelle Leander
Published: February 2020

Hydroxybenzoic acid esters are isolated on a column of silica gel while interferences are removed with petroleum ether. The preservatives are then eluted with petroleum ether-diethyl ether (8+2), derivatives are formed by reaction with bis(trimethylsilyl)acetamide, and the concentrations are determined by gas-liquid chromatography.
Microbiological Determination of Thiram
Authors: Rappe Andre , Mauquoy Guy , Baur Serge
Published: February 2020

A rapid and simple agar plate method has been developed for the microbiological determination of thiram, using Saccharomyces carlsbergensis ATCC 9080 as the test organism. With this organism, as little as 25 ng thiram/ well or 200 ng/disk can be detected, well below the levels that can be detected with either Bacillus licheniformis or Flavobacterium as the test strain. The assay has been applied to a dietetic food preparation.
Rapid Determination of γ-Aminobutyric Acid and Arginine in Orange Juice: Application to Detecting Adulteration
Authors: Vandercook Carl E , Price Ruth L
Published: February 2020

A rapid, semiautomated liquid chromatographic method has been developed for the determination of γ-aminobutyric acid and arginine in orange juice. Data have been gathered on these amino acids, total amino acids, titratable acidity, total phenolics, and soluble solids for several seasons of commercial California, Florida, Arizona, and foreign orange juice concentrates. Possible applications of the data for detecting adulterations were suggested but, for statistical significance, data from at least one additional season should be gathered.