bluuebunny/crossref_metadata_2025_split huggingface dataset:
Standardizing Soil Testing Methods
Authors: Sabbe Wayne 
Published: February 2020

Abstract
Soil tests are performed to determine the amount of nutrients available to plants so that fertilizer and lime recommendations can be formulated. In 1951, State soil testing laboratories had numerous extractants for determining phosphorus and potassium. Twenty years later, only 3 extractants each were used for phosphorus and potassium. In the United States, a regional approach produced standardized methods for several of the most common soil testing procedures. These detailed standard methods resulted from identifying procedural causes for variations in soil test results. For example, the amount of nutrient extracted varied by size and shape of extraction vessel and speed and time of shaking. Currently, terminology and expression of soil test results, and a search for a more universal soil extractant, i.e., one that can be used to determine several rather than a single nutrient, are 2 of the main areas of effort.
Multielement Emission Spectroscopic Analysis of Plant Tissue Using DC Argon Plasma Source
Authors: Debolt Darrell C 
Published: February 2020

Abstract
A method for elemental analysis of plant tissue, using the Spectraspan III with a dc argon plasma emission source, is presented. Values are reported for boron, phosphorus, zinc, manganese, magnesium, molybdenum, aluminum, iron, copper, calcium, and potassium. NBS Orchard Leaves and NBS Tomato Leaves Standard Reference Material and a soybean tissue sample from 7 separate sample preparations and ashings are analyzed. Instrument operation is relatively simple, with rapid startup. Analysis is fast, requiring only 1.25 min/sample. Results and standard eviations compare favorably with NBS certified values for most elements. Dry ashing is responsible for differing results in the analyses for iron and aluminum. The discrepancy for molybdenum cannot be explained at present.
Acid Digestion, Hydride Evolution Atomic Absorption Spectrophotometric Method for Determining Arsenic and Selenium in Foods: Part II. Assessment of Collaborative Study
Authors: Ihnat Milan , Thompson Brian K 
Published: February 2020

Abstract
Results obtained from the recent collaborative study of a hydride evolution atomic absorption spectrophotometric method for determining arsenic and selenium in foods have been studied intensively. Various parameters relating to the method have been considered: accuracy (excellent agreement between reference data and means over all laboratories for both model solutions and food samples; considerable bias for individual laboratories); precision within laboratory (repeatability coefficients of variation of 0.07–0.15) and among laboratories (reproducibility coefficients of variation of 0.13–0.28); frequency of outlying data from model solutions and biological samples (rejection rate from 9 to 29%); and detection limits (estimated as 80 and 120 ng/g for As and Se, respectively). Attempts were made to interrelate these parameters and to relate them to hydride generator characteristics and to other aspects of the procedure, namely, hydride generator type; absorba nee-time peak width; standard curve slope, linearity, and precision; sample type; reagent blank magnitude; collaborator experience with sample treatment and hydride generation procedures, and departures from prescribed sample treatment procedure. On the basis of information from 28 laboratories using 16 different types of hydride generation apparatus, conducting 700 complete analyses and 2400 analyte quantitations on reagent blanks, 3 model solutions, and 13 different reference food samples with levels of As and Se ranging from 0 to 15,000 and 0 to 4,000 ng/g, respectively, the authors conclude that the method suffers from both systematic error and imprecision, and hence recommend that the method not be adopted.
Comparison of Methods for Determination of Sulfur in Fertilizer: Collaborative Study
Authors: Thorpe Virginia A ,   Collaborators:, Bailey L , Erickson E , Fathergill L , Gehrke C , Holmes J H , Jones N , Lonn P , McAvoy R L , Moore E J , Price R N , Sensmeier R K , Silkey J R , Sweeney R A , Winters J M , Woodis T C 
Published: February 2020

Abstract
Methods with applications for total sulfur (sulfate, elemental sulfur) in dry fertilizers, for total sulfur (sulfate, sulfite, thiosulfate, sulfide) in liquid fertilizers, for total sulfur (elemental sulfur) in sulfur-coated urea and elemental sulfur formulations, and for thiosulfate sulfur in ammonium thiosulfate liquid fertilizer (12-0-0, 26 S), and 7 samples with background and directions were submitted to 12 collaborating laboratories for comparison to official methods 2.160–2.161 and 2.162. The methods studied are simple and rapid, and recover the total sulfur in fertilizers containing high levels of elemental sulfur and thiosulfate sulfur. Method 2.160–2.161 does not recover total sulfur in these products. The first 3 methods have been adopted as official first action, and the present official methods for sulfur, 2.160–2.161 and 2.162, have been repealed, official first action.
Isomer Specific Assay of Ester and Salt Formulations of 2-Methyl-4-chlorophenoxyacetic Acid and 2,4,5-Trichlorophenoxyacetic Acid by High Pressure Liquid Chromatography: Collaborative Study
Authors: Grorud Robert B , Stevens Timothy S ,   Collaborators:, Barry C , Fisher J R , Grimes G S , Hageman L , Hodgins E , Jones C , Klimstra W , Law M W , MacEachern G , Meyer D R , Plunkett R W , Rivera L , Stevens T S , Wong D L 
Published: February 2020

Abstract
HPLC methodology for ester and salt formulations of 2 methyl-4-chlorophenoxyacetic acid (MCPA) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-TA) has been substantiated in 2 collaborative studies. The methods closely follow the AOAC method for 2,4-dichorophenoxyacetic acid (2,4-DA), including preparation of samples by addition of a saponification internal standard solution to all samples. A microparticulate column in the reverse phase ion suppression mode separates all known impurities from the internal standard and MCPA, or 2,4,5-TA. The only differences in essential parameters between the 2 methods concern the internal standard, strength of solvent (acetonitrile), and pH of the acidic buffered eluant. One of the test samples is a combination of 2,4,5-TA and 2,4-DA as an ester formulation and each herbicide is quantitated on the same chromatogram. In respective acid equivalent, the coefficient of variation ranged from 1.67% for the 45% 2,4,5-TA ester formulation to 2.36% for the 22% 2,4,5-TA component in the combination ester formulation of 2,4-DA and 2,4,5-TA. There were 14 collaborators from the United States and Canada including 6 from industry and 8 from government agencies. The methods have been adopted as official first action.
Revised Method for Aflatoxins in Cottonseed Products, and Comparison of Thin Layer and High Performance Liquid Chromatography Determinative Steps: Collaborative Study
Authors: Pons Walter A , Lee Louise S , Stoloff Leonard ,   Collaborators:, Athnasios A K , Beebe R H , Francis O , Franz A O , Routh J H , Scott P M , Smiechowski R , Stubblefield R D , Theane J , Thorpe C , Trucksess M , Waltking A E 
Published: February 2020

Abstract
Modifications to save analyst time and reagents have been made in the rapid method for separation and quantitation of aflatoxins in cottonseed products. A collaborative study of the revised method, including optional high performance liquid chromatography (HPLC) in addition to thin layer chromatography for the determinative step, showed no change in the method precision or accuracy due to the modifications and no significant difference in the values obtained by either determinative procedure. The HPLC technique provided no significant difference in analysis repeatability, but did reduce the betweenlaboratory error component. The method has been adopted as official first action.
Determination and Confirmation of Identity of Aflatoxin M1 in Dairy Products: Collaborative Study
Authors: Stubblefield Robert D , Van Egmond Hans P , Paulsch Walter E , Schuller Pieter L ,   Collaborators:, Brawn P R , Everitt J , Franz A , Gamilinda I A , Jangula E , Jans J A , Jemmali M , Juskiewicz T , Kato T , Lee L , Kronert W , Meyer H , Ozaki M , Patterson D S P , Polzhofer K P , Shannon G M , Sizoo E A , Srebrnik S , Stemp A , Trucksess M , Tuinstra L G M T , Rensburg S J van , Veldhuizen C J van , Vick T , Webb M , Weissd G , Whitcomb D 
Published: February 2020

Abstract
An international collaborative study involving 23 collaborators was conducted to test methods, improved over previous methods with respect to speed and solvent use, for the rapid determination and thin layer chromatographic (TLC) confirmation of aflatoxin M1 identity in dairy products. For the quantitative method, collaborators assayed samples of Couda and cheddar cheeses, powdered milk, and butter containing levels of M1 near the anticipated limit of determination. Statistical analysis of the study results indicated that the lower limit of determination and precision of this method were comparable to these parameters of methods previously approved for analysis for aflatoxin M1. A few collaborators found that M1 eluted early from cleanup columns with cheese and butter samples and that emulsions formed during powdered milk sample extraction. The reasons for these problems have been determined and remedies are provided. For the TLC confirmation of identity method, collaborators prepared trifluoroacetic acid derivatives of M1 on the plates after 2-dimensional development. Concentrations as low as 0.3 ng/g cheese and 1.0 ng/g powdered milk were determined in this study. As a result of this study, both methods have been adopted as official first action methods by the AOAC and as reference methods by IUPAC.
Improved Monomolecular Fat Film Method for Determination of Yolk in Egg Albumen
Authors: Taber Lawrence E 
Published: February 2020

Abstract
The monomolecular film method can be simplified by an improved quantitation procedure. Following the extraction of the fat from the albumen and subsequent evaporation, the redissolved sample is applied to a round glass plate containing 1 in. pH 5 acetic acid solution topped by a film of oxidized oil sufficient to exhibit a color of third order green. The sample aliquot is dropped from a 100 μL Hamilton syringe directly at the center of the oil surface. A circular pattern results. The diameter of the pattern is measured in centimeters with a ruler placed under the glass plate. The area of the pattern is then calculated by the formula for the area of a circle.
Multiresidue Method for Determining N-Methylcarbamate Insecticides in Crops, Using High Performance Liquid Chromatography
Authors: Krause Richard T 
Published: February 2020

Abstract
A method is described for determining 7 carbamate insecticide residues (aldicarb, bufencarb, carbaryl, carbofuran, methiocarb, methomyl, and oxamyl) and 4 related carbamate metabolites (aldicarb sulfone, aldicarb sulfoxide, 3-hydroxy carbofuran, and methiocarb sulfoxide) on fruits, vegetables, and grains. Residues are extracted from the crops using methanol, and plant coextractives are removed using solvent partitioning and a charcoal-silanized Celite column. The carbamate residues are then separated on a reverse phase high performance liquid chromatographic (HPLC) column using an acetonitrile-water gradient mobile phase. The eluted residues are detected using an in-line post-column fluorometric detection technique. Recovery data were obtained by fortifying 9 crops (apples, carrots, green beans, green peppers, lettuce, oranges, soybeans, strawberries, and tomatoes) with the 7 carbamates and 4 carbamate metabolites. Except for aldicarb sulfoxide, pesticide recovery averaged 99% at both the 0.05 and 1.0 ppm fortification levels, with standard deviations of 5.0% (n = 86) and 5.6% (n = 87), respectively. The average recovery for aldicarb sulfoxide, a very polar carbamate metabolite, was 55 and 57% at the 0.05 and 1.0 ppm levels, respectively. An intralaboratory study of the method was conducted. Recovery data were obtained by fortifying grapes and potatoes with carbaryl, carbofuran, 3-hydroxy carbofuran, methiocarb, and methomyl at levels ranging from 0.05 to 15 ppm. Determinations were made in duplicate and the average recovery was 95% (range 87–101%).
Improved Microbiological Procedure for Determining Erythromycin in Milk and Some Milk Products
Authors: Harpster Carol P , Katz Stanley E 
Published: February 2020

Abstract
An improved microbiological assay for erythromycin in milk and some milk products was developed. Acidification of the samples to pH 4.5 resulted in precipitation of milk solids which were separated by centrifugation. The pH of the aqueous supernatant solution was readjusted to pH 8.0 to obtain maximum sensitivity. The sample cleanup and the use of a single, thin, seeded agar layer with Micrococcus lutea as the assay organism permitted the measurement of 0.05 μg/mL milk with recoveries averaging 84.0%, 0.50 μg/g nonfat dry milk with recoveries averaging 55.4%, 0.10 μg/g cream cheese with recoveries averaging 100.2%, and 0.05 μg/mL buttermilk with recoveries averaging 44.0%. The improved procedures showed superior recoveries and improved the ability to detect and measure lower levels when compared with commonly recommended assay procedures for erythromycin residues.
Determination of Extractable Mirex in Whole Blood
Authors: Stahr H Michael , Hyde Walter , Gaul Michael 
Published: February 2020

Abstract
A method for the determination of free mirex in blood has been developed in which whole blood is extracted with acetone–hexane (9+91), passed through Na2SO4, concentrated, and analyzed by electron capture gas-liquid chromatography (GLC). Results were highest for fresh blood. Recoveries were verified by determining 14C-labeled mirex before and after extraction. Little mirex was detected in the samples after extraction. Hydrolysis of residual blood indicates that a metabolite of mirex is released. The possible metabolite has a CLC retention time and mass spectrum which resemble hydroxy metabolites of mirex.
Evaluation of Milkoscan 104 Infrared Milk Analyzer
Authors: Voort F R Van De 
Published: February 2020

Abstract
The Milkoscan 104, a single cell, dual wavelength infrared milk analyzer, was assessed to see if it would meet the newly set AOAC specifications for accuracy and reproducibility required for official sanctioning of the instrument for milk component analysis. This assessment was carried out using herd, individual cow, commercial, and composite random milks, and produced mean differences and standard deviations of difference of &lt;0.02% and ±0.02% for reproducibility and &lt;0.05% and ±0.06% for accuracy. Results outside these values were encountered in the individual cow milks, for which the instrument was not specifically calibrated. The average molecular weight of the milkfat was an important variable because 2 anomalous milks were present in the calibration milks, thus restricting the overall accuracy obtainable. Linear regression analysis of chemical vs instrumental results showed good linearity and provided standard errors of the estimate of the same magnitude as the standard deviation of the differences. A separate assessment of the instrument for within- and between-day variation showed no practical significant differences. Based on the overall results, the Milkoscan 104 was judged to be capable of meeting the AOAC specifications set for fat, protein, and lactose analysis.
Spectrophotometric Determination of Rozol in Paraffinized Formulations
Authors: Kawano Yoshihiko , Chang Wanda 
Published: February 2020

Abstract
Rozol (2-[(ρ-chlorophenyl)phenylacetyl]-l,3-indandione) in paraffinized baits is extracted with benzene. The extract is placed on a Florisil column. Paraffin and other interfering substances are removed by washing with benzene, carbon disulfide, and hexane. Rozol is eluted with acidic ethanol. The eluate is analyzed with an ultraviolet spectrophotometer by scanning between 360 and 240 nm and measuring the absorbances at 350 and 321 nm. The amount of Rozol is calculated by comparison with a standard, and a correction is made from the recovery of a fortified sample. Recoveries from fortified samples averaged 93.7%. The linearity of measurement of Rozol at 321 nm ranges from 2 to 10 μg.
Gas-Liquid Chromatographic Method for the Analysis of Microencapsulated Ethyl Parathion and Methyl Parathion Insecticides: Collaborative Study
Authors: Karr James J ,   Collaborators:, Antles H D , Audino J B , Bontoyan W R , Carlstrom A A , Conner D , DiPilla E J , Ellis N D , Gentry G M , Gilmore P K , Hayes E , Helfant L J , Jensen D J , MacEachern G M , Bontoyan W R , Minyard J P , Topping A , Ullrich L , VandeLinde D C , Wargacki R E , Whitaker R 
Published: February 2020

Abstract
The determination of ethyl parathion in Penncap-E insecticide was studied collaboratively by 14 laboratories. The assay of methyl parathion in Penncap-M insecticide was studied by 8 laboratories. The original method which was adopted official first action for methyl parathion specified dimethoate, which is currently classified as a suspected carcinogen, as the internal standard. The current collaborative efforts were conducted as a supplemental study to evaluate the performance of the new internal standard, bis-2-methoxyethyl phthalate, and to test the gas-liquid chromatographic method for microencapsulated ethyl parathion (internal standard, dibutyl phthalate). The method uses essentially the same grinding and extraction with acetonitrile as the original study. At the 20% methyl parathion level, the standard deviation within laboratories was 0.186%, and among laboratories, 0.737%. Two formulations of ethyl parathion at approximately 16 and 24% were analyzed in replicate on 2 days by the same analyst, and provided excellent agreement within laboratories as well as among laboratories. The standard deviation (pooled) within laboratories was 0.284% and among laboratories, 0.518%. The method has been adopted as official first action.
Paired-Ion Chromatography and High Performance Liquid Chromatography of Labetalol in Feeds
Authors: Townley Edward R , Ross Bruce 
Published: February 2020

Abstract
A high performance liquid chromatographic (HPLC) method using reverse phase paired-ion chromatography and ultraviolet detection at 280 nm has been developed to determine labetalol, an alpha and beta adrenoceptor blocking agent, in Purina No. 5001 rodent chow. The method is simple and rapid, and demonstrates a separation technique applicable to other acidic and basic drugs. It requires only extraction of the drug with methanol–water–acetic acid (66+33+1) and separation of insoluble material by filtration before HPLC. Labetalol, is chromatographically separated from soluble feed components by means of a µBondapak C18 column and methanol–water–acetic acid (66+33+1) mobile phase, 0.005M with respect to sodium dioctylsulfosuccinate pairedion reagent. Average recovery is 98.7% with a relative standard deviation of ±2.3% for the equipment described.
High Pressure Liquid Chromatographic Determination of 5-(Hydroxymethyl)-2-Furaldehyde in Caramel Solution
Authors: Alfonso Felipe C , Martin Glenn E , Dyer Randolph H 
Published: February 2020

Abstract
An HPLC method is described for the detection of caramel color by measuring the level of 5-(hydroxymethyl)-2-furaldehyde (5-HMF). For the several products of caramelization examined, 5-HMF was the most sensitive indicator of the presence of caramel. The method specifies a reverse phase C18 column, a UV detector set at 277 nm, and a methanol-water gradient to separate 5-HMF from interfering substances. Other flavor compounds resolved by the same gradient are vanillin, ethyl vanillin, coumarin, benzaldehyde, caffeine, anethole, theobromine, and cinnamaldehyde.
Colorimetric Determination of Capsaicin in Capsicum Fruits
Authors: Bajaj Krishan L 
Published: February 2020

Abstract
A simple and accurate colorimetric method has been developed for quantitative determination of capsaicin in capsicum fruits. The method does not involve prior isolation of capsaicin from green capsicum fruits, and interference due to pigments is accounted for by determining a blank. Interfering substances are removed from red capsicum fruits by column chromatography using basic alumina as adsorbent. Capsaicin from the ethyl acetate extract of dried fruits is determined by developing a yellow complex with sodium nitrite–sodium molybdate reagent, which is read at 430 nm. Lambert-Beer’s law is obeyed in the concentration range 1.5–33.5 μg capsaicin/mL. The method is reproducible and is applicable to the rapid determination of capsaicin content.
Quality Assurance in the Analysis of Foods for Trace Constituents
Authors: Horwitz William , Kamps La Verne R , Boyer Kenneth W 
Published: February 2020

Abstract
An examination of the results of over 50 interlaboratory collaborative studies conducted by the AOAC on various commodities for numerous analytes shows a relationship between the mean coefficient of variation (CV), expressed as powers of 2, with the mean concentration measured, expressed as powers of 10, independent of the determinative method. Some typical CV values are: drug formulations at a 1% concentration, 2%; sulfonamides in feeds at a 0.01% concentration, 4%; pesticide residues and toxic elements, 10 6 (1 ppm), 16%; and aflatoxins 10 8 (10 ppb), 32%. Analytical work at trace levels must be constantly monitored through analysis of reference materials and surrogate samples, and by independent replication.
Ion-Pair High Performance Liquid Chromatography of Synthetic Water-Soluble Acid Dyes
Authors: Puttemans Marc L , Dryon Louis , Massart Désiré L 
Published: February 2020

Abstract
The ion-pair chromatography of food dyes is studied in 2 reverse phase HPLC systems. Tetrabutylammonium is used as counter ion in the mobile phase. In the first system, a C18 stationary phase and water-methanol eluants, the influence of methanol content and counter ion concentration was investigated. The second system, 1-pentanol coated on hydrophobic support as the stationary phase, gave higher retention times than did the first system with similar counter ion concentrations. The two systems complement each other and permit the complete separation of all dyes investigated.
New Brine Saturation Method for Extraction of Light Filth from Corn Meal: Collaborative Study
Authors: Freeman Clarence C ,   Collaborators:, Nagy J , Schafer P , Senff W A , Stricklin M , Trauba D , Velzen W Van , Washbon E , Whiteman A 
Published: February 2020

Abstract
An improved method has been developed for extracting light filth from corn meal. The proposed method uses only tap water, salt, olive oil, and alcohol, eliminating the need for costly and toxic solvents for the separation. Reports from 8 collaborators showed that recovery was 95.8% for insect fragments and 84.3% for rodent hairs by the proposed method, as compared with 90.6 and 88.6%, respectively, by the official method. The proposed method has been adopted as official first action to replace official method 44.042 for corn meal only.
pH Determination in Acidified Foods: Collaborative Study
Authors: Boland Frederick E , Lin Rong C , Mulvaney Thomas R , Mcclure Foster D , Johnston Melvin R ,   Collaborators:, Adkins D , Cox B , Durany G , Gould W A , Halaby G , Hill M , Hoffman C , Huhtanen C , Ito K , Klein P , Krout D , O’Korn F , Thorn J V , Yetts S 
Published: February 2020

Abstract
A proposed method for determining pH of acidified foods has been developed and subjected to collaborative study. The method appears to be both accurate and precise. Five samples consisting of pimientos, marinated pimientos, 2 pH buffer solutions, and chocolate syrup were sent to each of 12 collaborators along with a copy of the method. Two of the collaborators were FDA District laboratories while the remainder were representatives from industry, universities, and state health agencies. Many different types of pH meters and combinations of electrodes were used by the collaborators. The tabulated results from the collaborators are presented. The method has been adopted official first action.