bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generic Combustion Method for Determination of Crude Protein in Feeds:
Collaborative Study
Authors: Sweeney Rose A 
Published: February 2020

Abstract
Nine laboratories participated in a collaborative study on determination of crude protein in animal feeds to compare a generically described combustion method with the AOAC mercury catalyst Kjeldahl method (7.015). The combustion method was written in general terms of method principle, apparatus specifications, and performance requirements. The sample set comprised closely matched pairs of feed ingredients and mixed products ranging from 10 to 90% protein. Ten pairs ground to 0.5 mm were the focus of the study; 4 pairs were ground to 1.0 mm for comparison. Nicotinic acid and lysine monohydrochloride were included as standards. Collaborators were instructed to report their results for performance checks using materials supplied. Only one laboratory failed to meet the proposed limits. Seven laboratories used the LECO Model FP-228 analyzer and 2 used the LECO CHN 600 analyzer. For the 0.5 mm pairs, repeatability standard deviations (sr) ranged from 0.09 to 0.58 for the Kjeldahl method and from 0.14 to 0.33 for the combustion method, with a pooled sr value of 0.28 and relative standard deviation (RSDr) of 0.59%. Reproducibility standard deviations (SR) ranged from 0.23 to 0.86 (Kjeldahl) and from 0.30 to 0.61 (combustion), with a pooled sR value of 0.52 and RSDR of 1.10%. Grand means for the samples ground to 0.5 mm were 47.65% protein by the combustion method and 47.41% protein by the Kjeldahl method. For samples ground to 1.0 mm, corresponding values were 31.82 and 31.50% protein. The generic combustion method has been approved interim official first action.
Homogeneity of Meats Prepared for Analysis with a Commercial Food Processor:
Collaborative Study
Authors: Beebe Roberta M , Lay Eric , Eisenberg Sylvan 
Published: February 2020

Abstract
The food processor was evaluated as an alternative to the food chopper and bowl cutter for preparing meat samples for analysis in AOAC procedure 24.001. Samples of 6 meat types—cooked sausage, pork sausage, canned ham, hamburger, water-added ham, and smoked ham—were distributed to 9 laboratories for preparation using a food processor. The resulting 54 samples were sent to a USDA-accredited laboratory for analysis in triplicate for moisture, protein, and fat. Standard deviations and their 95% confidence intervals calculated for the analytical results were compared with USDA Performance Standards. With few exceptions, the upper limits were lower than the Performance Standards and for the exceptions, the intervals included the Performance Standards. By these criteria, the food processor is as effective in preparing homogeneous samples as the preparation procedures used to set the Performance Standards. Collaborators found the processor faster to use and easier to clean than the food chopper. Use of the food processor has received interim approval as an alternative to the food chopper or bowl cutter in AOAC procedure 24.001 for preparing meat samples for analysis.
Precision Parameters of Standard Methods of Analysis for Dairy Products
Authors: Peeler James T , Horwitz William , Albert Richard 
Published: February 2020

Abstract
The available collaborative studies for standard methods of analysis for various constituents of milk and milk products were examined in an attempt to assign specific repeatability and reproducibility precision parameters to these methods. The different collaborative assays for the primary constituents (moisture/solids, fat, protein), the nutritionally important elements (calcium, sodium, potassium, phosphorus), and miscellaneous analytes/physical constants (ash, lactose, salt, freezing point) produced different estimates of the precision parameters for the same method. A suitable summary of the precision estimates from collaborative studies is given by the reproducibility relative standard deviation, RSDR, which is relatively constant within a product and permits comparisons across products. An estimate of the variation of RSDR for an analyte from a number of collaborative studies is presented in terms of the median and 90% interval (the range of the centermost 90% of values). These estimates are only informative when a substantial number of independent studies are available for pooling the independent estimates to form a distribution of RSDR values. The RSDR for the determination of the primary constituents of milk and milk products is characterized by a median RSDR of 1% and a 90% interval of 0.3-3%, with RSDR estimates occasionally occurring below 0.3% and above 4%. These overall estimates appear to be independent of analyte, matrix, and method and apply to concentrations of primary constituents that range from about 2 to 80%. The repeatability relative standard deviation, RSDR, is unstable, although it tends to converge to about 0.5-0.7 X RSDR. Too few collaborative assays are available to characterize RSDR for the determination of certain other constituents (acidity, ash, lactose, salt, and the nutritionally important elements) unless RSDR values for different analytes, methods, and matrixes are pooled on the basis of similar analyte concentrations. When pooled, the RSDR values are generally better than predicted from the Horwitz equation, RSDR (%) = 2 exp (1—0.5 logioC), where C is the concentration expressed as a decimal fraction; all but one of 661 RSDR values are within the upper empirical limit of twice this curve.
Caffeine as Main Interfering Compound in Radioimmunoassay of Aflatoxin Bj in Coffee Samples
Authors: Rauch Pavel , VĺDen Ivan , DavĺDek Tomáś , VelĺŚek Jan , Fukal Ladislav 
Published: February 2020

Abstract
The content of caffeine in coffee extracts prepared for radioimmunoassay of aflatoxin Bi was determined by gas chromatography. The extracts from coffee beans and decaffeinated coffee contained 1.76- 4.60 and 0.71-0.85 g caffeine/kg, respectively. These concentrations of caffeine caused false results in radioimmunoassay of aflatoxin Bi in the range 1.0-2.8 μg/kg for coffee beans and 0.3-0.4 μg/kg for decaffeinated coffee.
Spectrophotometric Method for Measurement of Lactose in Milk and Milk Products by Using Dialysis
Authors: Mistry Vikram V , Hassan Hassan N , Baer Robert J 
Published: February 2020

Abstract
A simple method for measuring lactose in milk and milk products by using dialysis is described. A sample of milk, diluted milk powder, cultured buttermilk, or Cheddar cheese whey is dialyzed against water in a test tube at 45°C for 1.5 h. Lactose from the product is extracted into the water and Teles reagent is added. Absorbance was converted to percent lactose using a standard curve. Lactose obtained by the dialysis method was comparable to results obtained by the ultraviolet enzymatic and infrared methods. The method was not suitable for yogurt, which contains galactose that reacts with the Teles reagent. The new method for lactose measurement is simple and does not require precipitation of proteins, filtration, or centrifugation.
Liquid Chromatographic Method for Determination of Extractable Nitroaromatic and Nitramine Residues in Soil
Authors: Jenkins Thomas F , Walsh Mariannee , Schumacher Patricia W , Miyares Paul H , Bauer Christopher F , Grant Clarence L 
Published: February 2020

Abstract
An analytical method was developed to determine the concentration of nitroaromatic and nitramine residues in soil. Air-dried soil samples are ground with a mortar and pestle and extracted with acetonitrile in an ultrasonic bath. A portion of extract is diluted with aqueous CaCh to flocculate suspended particles, filtered, and analyzed by liquid chromatography. The method provides linear calibration curves over a wide range of concentration. Detection limits ranged from 0.03 to 1.27 ng/g. Recovery of spiked analyte was better than 80% for all analytes tested. Each step in the analytical procedure was optimized using spiked and field-contaminated soils. This optimization included tests to (1) assess the effectiveness and kinetics associated with various extraction methods, solvents, and soil-to-solvent ratios; (2) compare separations achievable using various combinations of reverse-phase columns and eluants; (3) assess analyte recovery and ease of use for various procedures to remove particles from extracts; and (4) document stability of soil extracts and analytical stock and working standards. A ruggedness test and a preliminary assessment at 2 other laboratories indicated that the method was sufficiently rugged to justify a full-scale collaborative test. A comparison of extraction kinetics for spiked soil vs field-contaminated soil revealed very different kinetic behavior, indicating it is unwise to develop extraction procedures based solely on spiked soils.
Formaldehyde Quantitation in Air Samples by Thiazolidine Derivatization:
Factors Affecting Analysis
Authors: Yasuhara Akio , Shibamoto Takayuki 
Published: February 2020

Abstract
A new method for the determination of trace levels of formaldehyde in air was developed and validated. The method is based on the reaction of formaldehyde with cysteamine to form thiazolidine. Air samples containing trace levels of formaldehyde were prepared from paraformaldehyde. The percent yield of formaldehyde from paraformaldehyde was 85.1 ± 1.14%. Air samples were bubbled into an aqueous cysteamine trap. Thiazolidine formed from formaldehyde and cysteamine in the trap was determined by gas chromatography with a fused silica capillary column and a nitrogen-phosphorus detector (NPD). The lowest detection level for thiazolidine was 17.2 pg, equivalent to 5.80 pg formaldehyde. The recovery efficiency of trace gas phase formaldehyde in air was greater than 90%. Formaldehyde levels in ambient laboratory air were 48.9-56.2 ppb (v/v).
Liquid Chromatographic Determination of Sulfite in Grapes and Selected Grape Products
Authors: Perfetti Gracia A , Joe Frank L , Diachenko Gregory W 
Published: February 2020

Abstract
A liquid chromatographic (LC) method is described for the determination of sulfite in grapes and certain grape products. Sulfite is extracted from grapes with aqueous formaldehyde solution buffered at pH 5; free sulfite is converted to hydroxymethylsulfonate (HMS), which is extremely stable at pH 3-7. Subsequent heating to 80°C for 30 min converts reversibly bound forms of sulfite to HMS. The extract is then analyzed by reverse-phase ion-pairing liquid chromatography, using a Cjg column and a mobile phase of aqueous 0.005M tetrabutylammonium ion in 0.05M acetate, pH 4.7, and a flow rate of 1 mL/min. Aqueous KOH is added to the eluate to convert HMS to free sulfite, which is then treated with 5,5'-dithiobis[2-nitrobenzoic acid]. This reaction produces the 3-carboxy-4-nitrothiophenolate anion, which is determined by measurement of electronic absorption at 450 nm. For grapes spiked with HMS at 5-20 ppm (as S02), recoveries ranged from 92 to 112%, with a coefficient of variation of 4.6%. The method was also used to determine sulfite in various grape products. Results were comparable to those obtained by the AOAC official Monier-Williams method.
Honey Protein as Internal Standard for Stable Carbon Isotope Ratio Detection of Adulteration of Honey
Authors: White Jonathan W , Winters Kenneth 
Published: February 2020

Abstract
Using the difference in stable carbon isotope ratio between a honey and its protein fraction permits objective evaluation of possible adulteration of honey with small amounts (7-20%) as well as larger amounts of corn or cane sugar. The present uncertainty in interpretation of results from pure honeys with 5,3C values outside the generally accepted limits for pure honey of —27.5%o to —23.5%o is eliminated; likewise TLC testing to resolve questionable samples with 5n C values between —23.5 and —21.5%o is not needed. Fifty certified samples of pure honey were used to establish criteria for purity, and 38 other samples with δ13C values in the “questionable” or “adulterated” range for the AOAC official method were tested. A difference of 1.0%o or more between honey and protein fractions is proposed to indicate adulteration.
Turbidimetric Microbiological Assay Results Calculated by a BASIC Computer Program
Authors: Anderson Ellen M 
Published: February 2020

Abstract
A BASIC computer program was used to calculate the results of microbiological vitamin assays. The program, which incorporates the official AOAC guidelines for microbiological methods, reduces the uncertainty inherent in manual curve plotting and interpolation and minimizes the human error of repetitive calculations. Because the BASIC programming language is well suited for use on self-contained personal computers, it can be easily adapted by small laboratories
Liquid Chromatographic-Electrochemical Determination of Ethylenethiourea in Foods by Revised Official Method
Authors: Krause Richard T 
Published: February 2020

Abstract
AOAC official method 29.119-29.125 was revised to determine ethylenethiourea (ETU) directly by a liquid chromatographic-electrochemical (LC-EC) determinative technique and to improve ETU recovery. ETU is extracted from food products with a methanolaqueous sodium acetate solution. A portion of the concentrated filtrate is added to a column of diatomaceous earth, and ETU is eluted with 2% methanol in methylene chloride to separate it from food coextractives, which are retained on the column. The eluate is collected in a siliconized flask and evaporated, the residue is dissolved in water, and 20 nL of solution is injected onto an LC graphitized carbon column. ETU is eluted from the LC column with a mobile phase of acetonitrile-aqueous 0.1M phosphoric acid-water (5 + 25 + 70), and the eluted ETU is detected by using an amperometric electrochemical detector equipped with a gold/mercury working electrode. Recovery data were obtained by fortifying 13 food products with ETU: baked potatoes; canned applesauce, mushrooms, creamed spinach, green beans, spinach, and tomatoes; cooked fresh cabbage and frozen collards; fresh celery and lettuce; grape jelly; and powdered sugar cake donuts. Raw celery was found to cause low ETU recoveries. Average percent recoveries of ETU from the other 12 food products were 92 with a standard deviation of 12 for the low (0.05 and 0.1 ppm) fortification levels and 90 with a standard deviation of 6 for the higher (0.5 and 1 ppm) fortification levels. The limits of quantitation were 0.01 and 0.02 ppm for food products with low and high sugar content, respectively.
Determination of Sulfite in Foods and Beverages by Ion Exclusion Chromatography with Electrochemical Detection: Collaborative Study
Authors: Kim Hie-Joon 
Published: February 2020

Abstract
A liquid chromatographic (LC) method for determination of total sulfite in foods and beverages by alkali extraction followed by ion exclusion chromatographic separation and electrochemical detection (IEC-EC) was collaboratively studied by 9 laboratories. Blind duplicate samples of starch, diluted lemon juice, wine cooler, dehydrated seafood, and instant mashed potatoes were analyzed without spiking and with added sulfite at 2 levels. The initial sulfite levels varied from 0 to 384 ppm S02, and the levels added varied from 10 to 400 ppm. The initial sulfite levels determined by the IECEC method and the Monler-Williams method were in good agreement. Recovery of added sulfite by the IEC-EC method was generally higher than that by the Monler-Williams method. Within-laboratory repeatability (RSDr) for the IEC-EC method varied from 4.4 to 26.0%, and overall reproducibility (RSDR) varied from 8.5 to 39.3 %. The collaborators found the method to be fast, sensitive, and easy to use, which makes it a useful alternative to the Monler-Williams method. The method has been adopted official first action.
Determination of Free (pH 2.2) Sulfite in Wines by Flow Injection Analysis: Collaborative Study
Authors: Sullivan John J , Hollingworth Thomas A , Wekell Marleen M , Meo Victor A , Etemad-Moghadam Ali , Phillips John G , Gump Barry H 
Published: February 2020

Abstract
A method for the determination of free sulfite In wine by flow injection analysis (FIA) is described. The method Involves liberation of sulfur dioxide from the wine at pH 2.2, with detection by decolorlzation of a malachite green solution. The method was collaboratively studied, and the results indicated an average reproducibility of 12% for white wine samples (average level 12.1 ppm S02) and 26% for red wine samples (average level 3.1 ppm). When the FIA method was compared to an aeration/oxidation method, the results Indicated a high degree of correlation between the 2 methods. The FIA method has been adopted by AOAC official first action.
Gas Chromatographic Method for Determination of Chlorpyrifos and Its Metabolite 3,5,6-Trichloro-2-Pyridinol (TCP) in Dates
Authors: Mourer Charles R , Hall Gregory L , Whitehead William E , Shibamoto Takayuki 
Published: February 2020

Abstract
A method is described for the determination of the Insecticide chlorpyrifos and its metabolite TCP in green, unprocessed, and processed dates with the seeds incorporated. After extraction, chloropyrifos is cleaned up using Florisil and analyzed using a gas chromatograph (GC) equipped with a nitrogen/phosphorus detector. TCP is derivatized using bis- (trimethylsilyl)-acetamide (BSA) to form the TCP-derivative and analyzed by a gas chromatograph equipped with a Hall electrolytic conductivity detector. Recoveries of chlorpyrifos from all fortified dates (0.05 and 0.1 ppm) ranged from 86 to 110 % with an average of 94.5 %. Recoveries of TCP from all fortified dates (0.1 and 0.2 ppm) ranged from 79 to 99% with an average of 86%. Limits of detection for chlorpyrifos and TCP in green, unprocessed, and processed dates were 0.02 and 0.05 ppm, respectively.
Slurries Introduction in Flow Injection Atomic Absorption Spectroscopic Analysis of Sewage Sludges
Authors: Martinez-Avila R , Carbonell V , De la guardia M , Salvador A 
Published: February 2020

Abstract
The direct introduction of slurries in flow Injection-flame atomic absorption spectroscopy has been studied using a single-channel manifold. The influence of flow Injection parameters on the sensitivity and accuracy of this procedure has been established. A method has been developed for the determination of copper, manganese, and lead In sewage sludge where batch digestion of the samples In a microwave oven is carried out before dilution. Both sensitivity and limit of detection of the flow Injection analysis procedure are adequate for the analysis of actual samples (the limit of detection was 0.06, 0.05, and 0.3 ppm for copper, manganese, and lead, respectively). The accuracy of the proposed method, determined from the analysis of 2 reference samples from the European Community Bureau, is better than that obtained by the continuous aspiration of the samples.
Amino Acid Analysis of Feeds in The Netherlands: Four-Year Proficiency Study
Authors: Van Der Meer Jos M 
Published: February 2020

Abstract
To improve accuracy and precision of amino acid analysis In 12 Dutch feed laboratories, a proficiency study was organized twice annually over a 4-year period. The method used included reflux acid hydrolysis for 22 h followed by evaporation, separation on a cation-exchange resin In an amino acid analyzer, and photometric detection after post-column derlvatlzatlon with ninhydrln. For the determination of sulfurcontaining amino acids, samples were oxidized prior to hydrolysis. For the determination of tryptophan, samples underwent an alkaline hydrolysis excluding oxygen, were separated by liquid chromatography on a Hypersil ODS analytical column, and were assayed by UV or fluorescence detection. The average relative standard deviations within (CVr) and between (CVR) laboratories were 3 and 7%, respectively. For some mixed feed samples, the results from the proficiency study were compared with those obtained by the International Analytical Group. For those samples, the relative standard deviation of the difference between IAG and Dutch groups was only 1.9%. For samples that were analyzed twice during this 4-year period, relative standard deviation of between-serles differences was only 2.1 %.
Influence of Automatic Dishwashings and Scrubbings on Release of Lead from Glazed Ceramicware
Authors: Gould John H , Hight Susan C , Alvarez George H , Nelson Catherine E , Capar Stephen G 
Published: February 2020

Abstract
Use of lead glazes on ceramicware and the release of lead from finished glazes are reviewed. Single units of ceramicware with Initial lead leach levels from &lt;0.1 to 470 /μg/mL were subjected to multiple automatic dishwashings with Intermediate scrubbing of the ware by plastic fiber pads. Ware was periodically leached with 4% acetic acid solution at room temperature for 24 h, and the solutions were analyzed for lead. Release of lead under these conditions Is discussed. Results Indicated that neither passive teachings nor multiple dishwashings and scrubbings can predict future lead-release characteristics of glazes and decorations.
Liquid Chromatographic Determination of Bromadiolone in Rodent Baits
Authors: Koppen Benny 
Published: February 2020

Abstract
A method Is described for the determination of bromadiolone in rodent bait formulations. Samples are Soxhlet-extracted using methanol as extractant and analyzed by reverse-phase liquid chromatography with UV detection at 280 nm. Chromatography is performed using a ODS-Hypersll (5 fim) column, which enables separation of the 2 diastereolsomers of bromadlolone. The sum of the peak areas of the diastereolsomers Is used for quantitation. The method was tested for precision, linearity, and recovery. Duplicate analyses of 10 formulation samples gave a mean relative standard deviation of 4.1%. Linearity was very good (correlation coefficient 0.9997) In the relevant concentration range. Recovery from spiked samples was 88.9 ±2.3%. The method is applicable to rodent bait formulations with bromadiolone content 0.005% and 0.01%.
Simplified Cleanup and Liquid Chromatographic Ultraviolet Determination of Linuron and Three Metabolites in Potatoes
Authors: Miliadis George E , Siskos Panayotis A , Vasilikiotis George S 
Published: February 2020

Abstract
A simple and efficient method Is presented for the extraction, cleanup, and liquid chromatographic (LC) determination of linuron and 3 of Its metabolites, 3-(3,4-dlchlorophenyl)-1- methyl urea (DCPMU), 3-(3,4-dlchlorophenyl) urea (DCPU), and 3,4-dlchloroanillne (DCA), in potatoes. Samples are extracted with acetone, partitioned into dlchloromethanehexane (1 + 1), and cleaned up using disposable silica cartridges. LC determination Is performed using a LIChrosorb NH2 5 pm column, with an Isopropanol-lsooctane gradient mobile phase and UV detection at 248 nm. Recoveries of linuron and 2 of the metabolites from untreated samples fortified at 0.02-2 jtg/g ranged from 80 to 102%, while recoveries for the metabolite DCA ranged from 60 to 78%. The detection limit was 0.015 jtg/g for linuron and each metabolite; the minimum quantitation level was 0.5 fig/g. The developed method was applied to potato samples from a field experiment
Improved Extraction of Atrazine and Metolachlor in Field Soil Samples
Authors: Huang Lee Q , Pignatello Joseph J 
Published: February 2020

Abstract
A method was developed for extraction of weathered residues of atrazine and metolachlor from field soils; soils had last been treated with commercial formulations of the herbicides 8-15 months prior to sample collection. Maximum yields were obtained by batch extraction at 75 °C for 2-16 h with methanol-water (80 + 20) In a sealed vial. Hydrolysis or other decomposition reactions were minor or negligible, depending on the extraction time. This method is an improvement over published methods that are validated by spike recoveries; the proposed method gives 1.7-1.8 times higher yields compared to shaking for 2 h at room temperature, and 1.3-1.8 times higher yields compared to Soxhlet extraction. The reproducibility of the method was better than 12%. The results underscore the Impact of nonequllibrlum sorption of organic compounds on analytical methodology and emphasize the need to validate extraction methods with field samples