bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Proficiency Testing To Evaluate the Ability of European Union National Reference Laboratories To Detect Staphylococcal Enterotoxins in Milk Products
Authors: Hennekinne Jacques-Antoine , Gohier Martine , Maire Tiphaine , Lapeyre Christiane , Lombard Bertrand , Dragacci Sylviane 
Published: February 2020

Abstract
The European Commission has designed a network of European Union-National Reference Laboratories (EU-NRLs), coordinated by a Community Reference Laboratory (CRL), for control of hygiene of milk and milk products (Council Directive 92/46/ECC). As a common contaminant of milk and milk products such as cheese, staphylococcal enterotoxins are often involved in human outbreaks and should be monitored regularly. The main tasks of the EU-CRLs were to select and transfer to the EU-NRLs a reference method for detection of enterotoxins, and to set up proficiency testing to evaluate the competency of the European laboratory network. The first interlaboratory exercise was performed on samples of freeze-dried cheese inoculated with 2 levels of staphylococcal enterotoxins (0.1 and 0.25 ng/g) and on an uninoculated control. These levels were chosen considering the EU regulation for staphylococcal enterotoxins in milk and milk products and the limit of detection of the enzyme-linked immunosorbent assay test recommended in the reference method. The trial was conducted according to the recommendations of ISO Guide 43. Results produced by laboratories were compiled and compared through statistical analysis. Except for data from 2 laboratories for the uninoculated control and cheese inoculated at 0.1 ng/g, all laboratories produced satisfactory results, showing the ability of the EU-NRL network to monitor the enterotoxin contaminant.
Determination of Total Vitamin C in Fruit Juices and Related Products by Liquid Chromatography: Interlaboratory Study
Authors: Brause Allan R , Woollard David C , Indyk Harvey E ,   Collaborators:, Acar J , Adadevoh K , Cherix G , Durst B , Eisele T , Elkins E , Foos J , Hammack S , Hammond D , Hesford F , Hischenhuber C , Hong V , Huang C J , Kirksey S , Kline L , Kruger D , Lawson M J , Lea A , Martin G , Parkih A , Weiss J , Wilhelmsen E , Woodward B , Wrolstad R , Zygmunt L 
Published: February 2020

Abstract
A interlaboratory study was conducted to evaluate a liquid chromatographic (LC) procedure for the determination of total vitamin C in foods at levels of 5–60 mg/100 g. Emphasis was placed on fruit juices, although selected foods were also included in the study. Following dissolution of sample in water, endogenous dehydroascorbic acid was converted to ascorbic acid by precolumn reduction with dithiothreitol at neutral pH. Total ascorbate was determined by C18 reversed-phase LC with a phosphate eluent at pH 2.5, incorporating dithiothreitol to maintain vitamin C in the reduced form, and UV detection at 254 nm. Seven types of fruit juices and foods were tested by 19 collaborators in 7 countries. Three duplicate juices and foods met the criteria for Youden pairs and yielded repeatability relative standard deviation of 5.80–14.66%. Reproducibility relative standard deviation ranged from 6.36 to 35.54% (n = 10) with HORRAT values of 0.82–4.04. The LC method is suitable for routine use in fruit products and foods containing &gt;5 mg/100 g vitamin C and is recommended for further validation by AOAC INTERNATIONAL and International Fruit Juice Union.
Fast and Easy Multiresidue Method Employing Acetonitrile Extraction/Partitioning and “Dispersive Solid-Phase Extraction” for the Determination of Pesticide Residues in Produce
Authors: Anastassiades Michelangelo , Lehotay Steven J , Štajnbaher Darinka , Schenck Frank J 
Published: February 2020

Abstract
A simple, fast, and inexpensive method for the determination of pesticide residues in fruits and vegetables is introduced. The procedure involves initial single-phase extraction of 10 g sample with 10 mL acetonitrile, followed by liquid–liquid partitioning formed by addition of 4 g anhydrous MgSO4 plus 1 g NaCl. Removal of residual water and cleanup are performed simultaneously by using a rapid procedure called dispersive solid-phase extraction (dispersive-SPE), in which 150 mg anhydrous MgSO4 and 25 mg primary secondary amine (PSA) sorbent are simply mixed with 1 mL acetonitrile extract. The dispersive-SPE with PSA effectively removes many polar matrix components, such as organic acids, certain polar pigments, and sugars, to some extent from the food extracts. Gas chromatography/mass spectrometry (GC/MS) is then used for quantitative and confirmatory analysis of GC-amenable pesticides. Recoveries between 85 and 101% (mostly &gt;95%) and repeatabilities typically &lt;5% have been achieved for a wide range of fortified pesticides, including very polar and basic compounds such as methamidophos, acephate, omethoate, imazalil, and thiabendazole. Using this method, a single chemist can prepare a batch of 6 previously chopped samples in &lt;30 min with approximately $1 (U.S.) of materials per sample.
Determination of Metals in Composite Diet Samples by Inductively Coupled Plasma-Mass Spectrometry
Authors: Melnyk Lisa Jo , Morgan Jeffrey N , Fernando Reshan , Pellizzari Edo D , Akinbo Olujide 
Published: February 2020

Abstract
A study was conducted to evaluate the applicability of inductively coupled plasma-mass spectrometry (ICP-MS) techniques for determination of metals in composite diets. Aluminum, cadmium, chromium, copper, lead, manganese, nickel, vanadium, and zinc were determined by this method. Atmospheric pressure microwave digestion was used to solubilize analytes in homogenized composite diet samples, and this procedure was followed by ICP-MS analysis. Recovery of certified elements from standard reference materials ranged from 92 to 119% with relative standard deviations (RSDs) of 0.4–1.9%. Recovery of elements from fortified composite diet samples ranged from 75 to 129% with RSDs of 0–11.3%. Limits of detection ranged from 1 to 1700 ng/g; high values were due to significant amounts of certain elements naturally present in composite diets. Results of this study demonstrate that low-resolution quadrupole-based ICP-MS provides precise and accurate measurements of the elements tested in composite diet samples.
Survey of Residual Tetracycline Antibiotics and Sulfa Drugs in Kidneys of Diseased Animals in the Aichi Prefecture, Japan (1995–1999)
Authors: Oka Hisao , Ito Yuko , Goto Tomomi , Minami Tamae , Yamamoto Isao , Matsumoto Hiroshi , Mizuno Yoshihisa , Tsuruta Masukiyo , Hayashi Itsuki 
Published: February 2020

Abstract
Animal kidneys were collected in order to survey the incidence of tetracycline (TC) antibiotics and sulfa (SA) drug residues in slaughtered animals that did not pass inspection for human consumption by the Japanese Food Sanitation Law and the Meat Inspection Law at the slaughterhouses in Aichi Prefecture, Japan, from April 1995 to March 2000. The kidneys were analyzed by AOAC Official Method 995.09 for TCs and our previously reported liquid chromatographic method for SAs. Among 292 animals (94 cattle and 198 pigs), 106 (36.6%) and 41 (14.0%) contained TCs and SAs, respectively, including chlortetracycline, 59 (20.2%); oxytetracycline, 47 (16.1%); sulfamonomethoxine, 35 (12.0%); sulfadimethoxine and sulfamethoxazole, each 2 (0.7%); and sulfamerazine and sulfisoxazole, each 1 (0.3%). A small number of animals (5 cattle and 9 pigs) contained more than one drug residue. The frequency of residue detections was significantly higher for TCs than SAs in both cattle and pig kidneys (p &lt; 0.001).
Determination of Chloramphenicol in Bovine Milk by Liquid Chromatography/Tandem Mass Spectrometry
Authors: Sørensen Lambert K , Elbæk Tina H , Hansen Helga 
Published: February 2020

Abstract
A rapid confirmatory liquid chromatographic/tandem mass spectrometic method was developed for determination of chloramphenicol in bovine milk. Chloramphenicol was extracted directly from milk by solid-phase extraction on a C18 cartridge. The extract was further cleaned up on neutral aluminium oxide. Three transition products were monitored in negative ion mode after atmospheric pressure chemical ionization. The detection capability related to the transition product of lowest abundance was 0.03 μg/kg. The mean recovery was 90% at levels of 0.1–0.2 μg/kg. The relative repeatability standard deviations were 4.3, 3.8, and 2.8% at levels of 0.1, 0.2, and 1.0 μg/kg, respectively.
Determination of Phenylalanine and Tyrosine by Liquid Chromatography/Mass Spectrometry
Authors: Andrensek Samo , Golc-Wondra Alenka , Prosek Mirko 
Published: February 2020

Abstract
Phenylketonuria is a common metabolic disorder disease. Those affected appear normal at birth, but without treatment they develop severe psychomotor retardation. Throughout life, they must control their blood levels of phenylalanine (Phe) and consume a diet containing adequate amounts of Phe and tyrosine (Tyr). We have developed a liquid chromatographic/mass spectrometric (LC/MS) method for the quantitative evaluation of Phe and Tyr in food samples. This method takes advantage of the good separation of LC and the selective and reliable quantification provided by MS in the electrospray ionization mode. The LC/MS method is very suitable for the determination of selected amino acids in various matrixes. It is sensitive to levels as low as about 0.30 ppm for Tyr and 0.70 ppm for Phe and robust. Nearly 100 nondietary food samples were analyzed by the developed method.
Effectiveness of Temperature Modification in Decreasing the Bias in Milk Fat Test Results Between the Babcock and Ether Extraction Methods
Authors: Lynch Joanna M , Barbano David M , Healy Patrick A , Fleming J Richard 
Published: February 2020

Abstract
Both the Babcock (AOAC Method 989.04, revised Final Action 2000) and modified Mojonnier ether extraction (AOAC Method 989.05) methods are used in the dairy industry to determine the fat content of milk. Prior to revision in 1997, the Babcock method gave consistently higher fat test results than did the ether extraction. In 1997, a modification of the Babcock method was introduced to bring the results of the Babcock test into closer agreement with the ether extraction. The Babcock method was modified by lowering the temperatures used at various points in the method from about 57.5 to 48°C to increase the density of the material in the Babcock column. A collaborative study of the modification indicated it was successful in bringing the Babcock and ether extraction results into agreement but suggested that performance of the modified method was not as good as that of the unmodified method. In the present study, substantial evidence is presented to validate the success of the Babcock modification in bringing test results into agreement with ether extraction, and to document that temperature modification does not adversely affect method performance. Data were evaluated from an on-going proficiency testing program where 8–15 laboratories tested 7 milk samples in blind duplicate once every 2 months. Laboratories used the unmodified method from 1995 through 1996 and the modified method from 1998 through 1999. Compared with ether extraction, test results from the unmodified Babcock test were consistently higher by an average of 0.022% fat. For the modified Babcock test, average test results were –0.003% fat lower than with ether extraction and not significantly different from zero. AOAC method performance statistics (within-and between-laboratory precision) were equivalent for both the unmodified (Sr = 0.027, SR = 0.041, RSDr = 0.73%, RSDR = 1.08%) and modified (Sr = 0.023, SR = 0.038, RSDr = 0.60%, RSDR = 1.02%) Babcock methods. Modification of the Babcock method was successful in bringing test results into agreement with those of ether extraction.
3M™ Petrifilm™ Enterobacteriaceae Count Plate Method for Enumeration of Enterobacteriaceae in Selected Foods: Collaborative Study
Authors: Silbernagel Karen M , Lindberg Kathryn G ,   Collaborators:, Beatty S , Bell K , Boylston T , Brock G , Bryant L , DeSmet M , Eifert J , Grzanek K , Pulasani S , Saunders L , Scantling M , Wilson P 
Published: February 2020

Abstract
The practice of detecting and enumerating all oxidase-negative, glucose-fermenting-Gram-negative rods (i.e., the family Enterobacteriaceae) isused to indicate unsanitary or inadequate food processing conditions. The objective of this interlaboratory collaborative study was to evaluate and compare the methods described in Standard Methods for the Examination of Dairy Products (SMEDP) and the Compendium of Methods for the Microbiological Examination of Foods (Compendium) with a commercial product, the 3M™ Petrifilm™ Enterobacteriaceae Count Plate, for the recovery of Enterobacteriaceae in foods. Six foods—cheddar cheese, milk, flour, frozen prepared meals, frozen broccoli, and nut pieces—were analyzed for Enterobacteriaceae by 12 collaborating laboratories. For each food tested, the collaborators received 8 blind test portions consisting of a control test portion and 3 levels of inoculated test portion, each in duplicate. Each test portion was tested by the Petrifilm Enterobacteriaceae Count Plate method as well as the SMEDP or Compendium methods. The precision estimates (repeat-ability or within-laboratory variation, and reproducibility or between-laboratory variation) were calculated with standard statistical techniques.
Policy on Characterization of Antibodies Used in Immunochemical Methods of Analysis for Mycotoxins and Phycotoxins
Authors: Fremy J Marc , Usleber Ewald ,   Collaborators:, Chu F , Garthwaite I , Lee A , Maragos C , Ware G 
Published: February 2020

Abstract
The purpose of this document is to provide a policy on antibody characterization for conducting AOAC collaborative studies for immunochemical methods submitted for AOAC®Official MethodsSM Program status. The policy defines recommended information and characteristics to be provided by the Study Director, in the protocol of the collaborative study, for approval by AOAC. The document specifies parameters for characterization of antibodies used as biological reagent in the protocol of validation of immunochemical methods for the determination of mycotoxins and phycotoxins. These recommendations are applicable to the validation of any method, whether proprietary or non-proprietary, that is submitted to AOAC for Official Methods of AnalysisSM status recognition.
Computation of HORRAT Values
Authors: McClure Foster D , Lee Jung-Keun 
Published: February 2020

Abstract
The formula for the Horwitz ratio (HORRAT) as presented in the Study Director's Manual of AOAC INTERNATIONAL is applicable only when the concentration is in the unit/unit form (e.g., μg/μg, g/g, etc.). When the analyte concentration is a trace or mass fraction amount (e.g., μg/g), the formula generates incorrect HORRAT values. Alternative calculation procedures are presented to circumvent such problems.
Crude Fat, Diethyl Ether Extraction, in Feed, Cereal Grain, and Forage (Randall/Soxtec/Submersion Method): Collaborative Study
Authors: Thiex Nancy J , Anderson Shirley , Gildemeister Bryan ,   Collaborators:, Adcock W , Boedigheimer J , Bogren E , Coffin R , Conway K , DeBaker A , Frankenius E , Gramse M , Hogan P , Knese T , MacDonald J , M�ller J , Royle R , Russell M , Shafiee F , Shreve B , Sieh J , Spann M , Töpler E , Watts M 
Published: February 2020

Abstract
A method for determining crude fat in animal feed, cereal grain, and forage (plant tissue) was collaboratively studied. Crude fat was extracted from the animal feed, cereal grain, or forage material with diethyl ether by the Randall method, also called the Soxtec method or the submersion method. The proposed submersion method considerably decreases the extraction time required to complete a batch of samples. The increase in throughput is very desirable in the quest for faster turnaround times and the greater efficiency in the use of labor. In addition, this method provides for reclamation of the solvent as a step of the method. The submersion method for fat extraction was previously studied for meat and meat products and was accepted as AOAC Official Method 991.36. Fourteen blind samples were sent to 12 collaborators in the United States, Sweden, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.09 to 9.26% for crude fat. Among-laboratory (including within) relative standard deviation (reproducibility) ranged from 1.0 to 21.0%. The method is recommended for Official First Action.
Comparison of Solid-Phase Extraction and Micro-Solid-Phase Extraction for Liquid Chromatography/Mass Spectrometry Analysis of Pesticides in Water Samples
Authors: Famiglini Giorgio , Trufelli Helga , Pierini Elisabetta , De Simoni Elisa , Mangani Filippo , Cappiello Achille 
Published: February 2020

Abstract
Our recent on-line solid-phase extraction (SPE) device for micro-liquid chromatography, known as micro-solid-phase extraction (μSPE), was compared with traditional SPE for the analysis, from aqueous samples, of 4 pesticides belonging to different classes. Two different kinds of adsorbents, C18 and graphitized carbon black, were tested. A 2-stage ion trap mass spectrometer, equipped with homemade microflow electrospray ion (ESI) source, was used. Detection limits with a signal-to-noise ratio of 3:1 for both extraction methods were in the range of 0.1 μg/L for all compounds. However, better recoveries were obtained when μSPE traps were used.
A Technique to Recover Tracer as Carboxyl–Carbon and α-Nitrogen from Amino Acids in Soil Hydrolysates
Authors: Marsh Kerri L , Mulvaney Richard L , Sims Gerald K 
Published: February 2020

Abstract
Isotope analysis of biochemical compounds provides an unequivocal means for detecting assimilation of tracer C and N into microbial biomass. A diffusion method recently developed to determine amino acid-N by ninhydrin oxidation of soil hydrolysates was modified to permit simultaneous collection of the CO2 liberated during this oxidation. In the technique described herein, this is accomplished after removal of (NH4+ + amino sugar)–N, by performing ninhydrin oxidation at 90°C for 7 h in a 1.9 L Mason jar sealed with a lid equipped to support a petri dish containing 5 mL 0.2N NaOH. Recoveries of carboxyl-C and α-N ranged from 98 to 101% in evaluations with standard solutions of amino acids, whereas these recoveries exceeded 90% for 14C and 94% for 15N when soil hydrolysates amended with labeled amino acids were analyzed.
Speciation of Arsenic in Chicken Meat by Anion-Exchange Liquid Chromatography with Inductively Coupled Plasma-Mass Spectrometry
Authors: Polatajko Aleksandra , Szpunar Joanna 
Published: February 2020

Abstract
A method was developed for speciation analysis of arsenic in chicken meat. Different procedures were optimized for the recovery of arsenic compounds without destroying the original compounds, and 2 anion-exchange liquid chromatography columns were compared for the separation of arsenic species prior to on-line detection by inductively coupled plasma-mass spectrometry. The 2 species found were dimethylarsinic acid (106 ± 5 ng/g) and arsenobetaine (37 ± 4 ng/g). The stability of arsenic species in a chicken meat candidate reference material for at least 12 months was demonstrated.
Gas Chromatographic/Mass Spectrometric Determination of Flumioxazin Extracted from Soil and Water
Authors: Ferrell Jason A , Vencill William K 
Published: February 2020

Abstract
A method was developed for determining flumioxazin in soil and water. Recovery efficiencies for solid-phase extraction (SPE) of flumioxazin from deionized, well, and surface water were between 72 and 77%. SPE was superior to liquid–liquid extraction, using water–hexane and water–chloroform emulsions, which resulted in retrieval efficiencies of 25 and 22%, respectively. However, liquid–liquid extraction with ethyl acetate improved recovery of total flumioxazin to &gt;64%. Extraction from soil samples by direct solvent/soil extraction methods recovered between 18 and 76% of applied flumioxazin, depending on the solvent combination used. However, the use of accelerated solvent extraction techniques resulted in a 106 ± 8% recovery of flumioxazin from soil. In analysis by capillary gas chromatography with mass selective detection, flumioxazin had a calculated limit of detection of 9 ng/mL with a retention time of 16.66 min.
Quantitative Determination of Paralytic Shellfish Poisoning Toxins in Shellfish Using Prechromatographic Oxidation and Liquid Chromatography with Fluorescence Detection: Interlaboratory Study
Authors: Lawrence James F , Niedzwiadek Barbara , Menard Cathie ,   Collaborators:, Biré Ronel , A. Burdaspal Pedro , Ceredi Alfiero , Davis Brad , Dias Elsa , Eaglesham Goeff , Franca Susana , Gallacher Susan , Graham Dave , Hald Benedicte , Heinze Lutz , Hellwig Egon , M. Jonker Klaas , Kapp Katrin , Krys Sophie , Kurz Karl , Lacaze Jean-Pierre , Gago Martinez Ana , McNabb Paul , Ménard Cathie , Milandri Anna , Nsengiyumva Chrysostome , Pereira Paulo , Pineiro Nuria , Poletti Roberto , Riddell Greg , Rojas de Astudillo Luisa , Selwood Andy , Stern Alfred , Tiebach Reinhard , van den Top Hester , P. van Egmond Hans , Wezenbeek Paul , Chang Yen Ivan 
Published: February 2020

Abstract
An interlaboratory study was conducted for the determination of paralytic shellfish poisoning (PSP) toxins in shellfish. The method used liquid chromatography with fluorescence detection after prechromatographic oxidation of the toxins with hydrogen peroxide and periodate. The PSP toxins studied were saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins 2 and 3 (GTX2,3 together), gonyautoxins 1 and 4 (GTX1,4 together), decarbamoyl saxitoxin (dcSTX), B-1 (GTX5), C-1 and C-2 (C1,2 together), and C-3 and C-4 (C3,4 together). B-2 (GTX6) toxin was also included, but for qualitative identification only. Samples of mussels, both blank and naturally contaminated, were mixed and homogenized to provide a variety of PSP toxin mixtures and concentration levels. The same procedure was followed with samples of clams, oysters, and scallops. Twenty-one samples in total were sent to 21 collaborators who agreed to participate in the study. Results were obtained from 18 laboratories representing 14 different countries.
Studies of Polyester Fiber as Carrier for Microbes in a Quantitative Test Method for Disinfectants
Authors: Miner Norman , Harris Valerie , Stumph Sara , Cobb Amanda , Ortiz Jennifer 
Published: February 2020

Abstract
Tests were conducted by a Task Force on Disinfectant Test Methods that was appointed to investigate controversies regarding the accuracy of AOAC test methods for disinfectants as presented in AOAC's Official Methods of Analysis, Chapter 6. The general principles for new and improved AOAC tests are discussed, and a disinfectant test using microbes labeled onto a polyester fiber surface is described. The quantitative test measures the survival of test microbes as a function of exposure time as well as the exposure conditions required to kill 6 log10 of the test microbes. The time required was similar to that for the kinetics of the kill of Bacillus subtilis-labeled cylinders as tested by methods of the AOAC Sporicidal Test 966.04.
New Internal Standard for Quantitative Determination of Oxyphytosterols by Gas Chromatography
Authors: Grandgirard André , Cabaret Stéphanie , Martine Lucy , Berdeaux Olivier 
Published: February 2020

Abstract
A study was conducted to develop a new internal standard for the quantitative determination of oxyphytosterols. Tests on 5α-androsten-3β,17β-diol; 5α-androstan-3β, 17β-diol; 5-pregnen-3β,20α-diol; and 5α-pregnan-3β,20β-diolshowed that these compounds were not fully adequate. However, the compound 3β,22-dihydroxy-20-homo-5-pregnene, synthesized in 4 steps, resulted in a promising internal standard, with a molecule similar to hydroxysterols; retention time as trimethylsilyl in gas chromatography comprised between 5α-cholestane and 7α-hydroxycholesterol; clear mass spectrum in electronic impact mass spectrometry, with several intense ions suitable for selected ion monitoring-mass spectrometry. Further studies are necessary to observe the behavior of these compounds during the entire analytical procedure.