bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Chromatographic/Mass Spectrometric Confirmation of Identity of Coprostanol in Mercenaria mercenaria (Bivalvia) Taken from Sewage-Polluted Water
Authors: Matusik Jean E , Hoskin George P , Sphon James A 
Published: February 2020

Abstract
Coprostanol is a major fecal sterol in humans and may, therefore, be a good indicator of sewage-polluted waters. Some types of edible seafood, such as clams, that live in these waters may be contaminated with coprostanol. Coprostanol from clam tissue extracts had been previously quantitated by gas chromatography (GC). In the present work, capillary column GC was used to separate coprostanol, and electron ionization mass spectrometry was used to confirm its identity. Confirmation of identity of coprostanol at the 75 ng level was obtained by comparing the spectrum of the authentic standard with spectra of the clam tissue extract obtained under the same instrumental conditions. Various other compounds can be eliminated as potential interferences by virtue of either their different GC retention times or their spectra.
Enhanced Surveillance of Foodborne Mycotoxins by Immunochemical Assay
Authors: Pestka James J 
Published: February 2020

Abstract
Mycotoxins are a chemically diverse group of fungal secondary metabolites with a wide range of toxic effects. Conventional thin-layer and instrumental methods of mycotoxin analysis are time-consuming and make routine safety and quality control screening of these compounds in agricultural commodities difficult. As an alternative, specific polyclonal and monoclonal antibodies have been raised against mycotoxin-protein conjugates and used in sensitive radioimmunoassays (RIAs) and enzyme-linked immunosorbent assays (ELISAs). One of the simplest ELISA approaches involves competition for a solid-phase antibody between a mycotoxin-enzyme conjugate and an unconjugated mycotoxin in the sample extract. ELISAs have been developed for aflatoxins B, and M„ zearalenone, T-2 toxin, and deoxynivalenol, which are highly specific, rapid (10 min), easily adaptable for analyzing large numbers of samples, and directly applicable to assaying methanol-water extracts of a wide range of foods. Several commercial mycotoxin ELISAs using this approach (most typically for aflatoxin B,) are currently being marketed. Since ELISAs will be used in large part by personnel with limited technical expertise, individual kits must be critically evaluated by analytical chemists for suggested sampling procedures, efficiency of extraction, crossreactivity, mycotoxin recovery, assay reproducibility, and product shelf-life prior to routine use in food safety and quality control screening
Electrophoretic Methods for Screening for Antibiotics in Animal Feeds
Authors: Salvatore Michael J , Katz Stanley E 
Published: February 2020

Abstract
A new system for screening antibiotics in animal feeds involves washing antibiotic-containing animal feeds with a series of organic solvents to eliminate interferences and partially separate the antibiotics. Antibiotics are then determined by using paper electrophoresis and thin-layer bioautography. This approach enables the separation and qualitative identification of 17 antibiotics currently used in animal feeds and provides the ability to detect low-level cross-contamination
Nicotine Analysis of Commercial Tobacco Products
Authors: Gottscho Alfred M , Lin Jeen-Lee , Duck William N , Losty Thomas A 
Published: February 2020

Abstract
The use of AOAC standard methods for the determination of nicotine in commercial tobacco products is shown to be inappropriate. The methods do not provide for suitable sample preparation of these products for the analysis and, in addition, they yield high results. Evidence is presented that the nicotine or total alkaloids measured includes artifact nicotine. The distillation method was developed at a time when the complex alkaloid chemistry of tobacco was unknown, and does not take into consideration the possible contribution of substances in tobacco capable of contributing falsely to the result. The Cundiff-Markunas method, developed more recently, also fails to account for this effect—probably because it was designed to produce results matching those of the distillation method. Replacement of the standard methods is proposed and some alternative procedures are suggested
Dimetridazole Residues in Pork Tissue. I. Assay by Liquid Chromatography with
Electrochemical Detector
Authors: Carignan Germain , Skakum William , Sved Stephen 
Published: February 2020

Abstract
A liquid chromatographic (LC) method with electrochemical detection in the reductive mode was developed for the quantitative determination of dimetridazole (DMZ) and its major metabolite (HMMNI) at residue levels in pork tissue. For blood plasma, a sample is precipitated with 2 volumes of acetonitrile and centrifuged, and a diluted aliquot of the supernatant liquid is chromatographed. For muscle, a 10 g sample is extracted 3 times with dichloromethane. After evaporation of the combined extracts, the residue is redissolved in a mixture of hexane and mobile phase (0.3% TEA in 0.6M ammonium acetate pH 5.0 and acetonitrile, 85 + 15) and centrifuged, and an aliquot of the lower phase is chromatographed. Chromatography is accomplished using valve switching with 2 liquid circuits, employing the same mobile phase for both. The sample is deaerated by sparging with helium under slight positive pressure to prevent rediffusion of the oxygen. The sample is first loaded into a deoxygenator and the flow is stopped for complete deoxygenation. The flow is then resumed to transfer the sample into the first, low back-pressure column (ODS, 10 μm, 4.6 x 200 mm). Switching the valve at this point removes the deoxygenator from the circuit and connects the first column to a second one (ODS, 5 μm, 4.6 x 150 mm) in tandem. After the effluent is passed through a second deoxygenator to reduce the residual oxygen in the mobile phase, it is monitored by an electrochemical detector with a screened wall jet cell and a gold mercury electrode, set at —1.2 V. The response is linear, in the ranges studied: 100-1000 pg for DMZ and 200-1000 pg for HMMNI. Mean recoveries for the extraction method are 56 and 70% for DMZ and HMMNI, respectively, using spiked meat and plasma samples at 0.26-2 ppb. Essentially 100% recoveries are obtained with spiked (10 ppb) plasma, using the acetonitrile precipitation
Determination of Acid-Detergent Fiber and Crude Protein in Forages by Near-Infrared
Reflectance Spectroscopy: Collaborative Study
Authors: Barton II Franklin E , Windham William R 
Published: February 2020

Abstract
A Collaborative Study Was Conducted To Determine The Standard Error Of Difference Among Laboratories For Near-Infrared Reflectance Spectroscopic (Nirs) Determination Of Acid-Detergent Fiber (Adf) And Crude Protein In Forages. The 6 Participating Laboratories Were Members Of The Usda/Ars National Near-Infrared Reflectance Spectroscopy Forage Research Project. The Nirs Calibration Equations Were Developed In The Associate Referee's Laboratory For Crude Protein And Adf And Were Transferred To The Instrument In Each Of The Other Collaborating Laboratories. The Calibration Set Included Over 650 Diverse Forage Samples With Crude Protein And Adf Calibration Data; The Validation Set Included 94 Samples Of Bermudagrass. Amonglaboratory Reproducibility For The Nirs Method, Calculated As The Relative Standard Deviation For Reproducibility (Rsdr), Was 1.14% For Adf And 0.42% For Crude Protein. The Variance Component For Among-Laboratory Variation (Coefficient Of Variation) Was 2.54% For Adf And 2.89% For Crude Protein. These Results Confirm That It Is Possible To Calibrate, Validate, And Transfer (Nirs) Equations And Data Among Laboratories For The Accurate Determination Of Adf And Crude Protein, And Thereby Demonstrate That Nirs Can Be Used As A Standard Method For The Analysis Of Forages. The Method Has Been Adopted Official First Action
Spectrophotometric Determination of Cyclamate in Soft Drinks and Desserts:
Complementary Collaborative Study
Authors: SJÖBERG Anna-Maija K 
Published: February 2020

Abstract
Fifteen official food control laboratories participated in a collaborative study of a spectrophotometric method to determine cyclamate in a soft drink and a dessert at concentrations of 90-311 mg/L and 202-526 mg/kg, respectively, with blind duplicates and a blank. Average recovery from the soft drink was 97.5%, and from the dessert, 98.6%. Reproducibility relative standard deviations were 4.7-6.5% and 6.9-8.5%, respectively. The outlier percentage was 5.5%. This study complements an earlier work by leading Nordic food laboratories and was designed according to the latest recommendations. The results of this study were compared with those of the earlier collaborative study and with general collaborative results obtained by AOAC.
Investigations on N-Nitrosopyrrolidine in Dry-Cured Bacon
Authors: Fiddler Walter , Pensabene John W , Gates Robert A , Foster Judith M , Smith Wertice J 
Published: February 2020

Abstract
Dry-cured or "country-style" bacon is a low volume specialty product typically made by small producers whose production practices vary widely. These practices include the direct application of dry-cure formulations containing varying concentrations of salt, sugar, flavoring agents, sodium nitrite, and sometimes sodium nitrate, and the use of lengthy curing and processing times. Because of the possibility of generating higher levels of N-nitrosopyrrolidine (NPYR) after frying in this product type compared with pump-cured bacon, an investigation was carried out on dry-cured bacon obtained from cooperating state or federally inspected establishments. Three different samples from each of the 16 plants were analyzed. Only one sample from each of 2 different producers exceeded the Food Safety and Inspection Service (FSIS) action level of 17 ppb NPYR, indicating that the majority of samples tested were in compliance. A significant correlation (P &lt; 0.01) was found between residual NaN02 prior to frying and NPYR after frying. The elimination of added nitrate in the dry-cure formulations is recommended.
Application of Near Infrared Reflectance Spectroscopy to Determination of Fat in Cheddar Cheese
Authors: Wehling Randy L , Pierce Michelle M 
Published: February 2020

Abstract
Near infrared reflectance (NIR) "spectroscopy was used to determine the fat content of Cheddar cheese. Through multiple linear regression, calibrations were developed for use with a commercial filter monochromator instrument. A 6-wavelength calibration, using 1734 nm as the primary indicator wavelength, was found to perform satisfactorily. Averaging readings from duplicate sample repacks reduced the standard error of performance (SEP) compared with the use of single readings. For a validation set of 23 samples, the correlation coefficient squared (r2) between the NIR and Roese-Gottlieb methods was 0.92, with an SEP of 0.44%. Both sample temperature and age of the cheese influenced the NIR response.
Liquid Chromatographic Determination of Carminic Acid in Yogurt
Authors: Jalón Mercedes , Peńa Majesús , Rivas Julián C 
Published: February 2020

Abstract
A reverse-phase liquid chromatographic method is described for the determination of carminic acid in yogurt. A C18 column is used with acetonitrile-1.19M formic acid (19 + 81) as mobile phase and diode array detection. Sample preparation includes deproteinization with papain and purification in a polyamide column. The relative standard deviation for repeated determinations of carminic acid in a commercial strawberry-flavored yogurt was 3.0%. Recoveries of carminic acid added to a natural-flavored yogurt ranged from 87.2 to 95.3% with a mean of 90.2%. The method permits measurement of amounts as low as 0.10 mg/kg.
Determination of Maduramicin by Liquid Chromatography with Atomic Absorption Spectrometric Detection
Authors: Johnson Nelson A 
Published: February 2020

Abstract
A liquid chromatograph was interfaced to an atomic absorption spectrometer for the detection and quantitation of maduramicin in feed matrixes at the 1-8 ppm level. Ionophores in general form strong 1:1 products with various metal cations, yielding complexes that are insoluble in water but very soluble in organic solvents. Maduramicin, a carboxylic, polyalcohol, polyether antibiotic, is labeled with the sodium cation and analyzed by atomic absorption spectroscopy (AAS). The lower limit of detection is approximately 100-200 ng maduramicin sodium salt. Feeds containing 1-8 ppm maduramicin are extracted with acetone, the extract is passed through an alumina column, the column is eluted with acetonitrile-water (90 + 10), and the eluate is analyzed for maduramicin by liquid chromatography- AAS after concentration and conversion of maduramicin to the sodium salt. Recoveries of maduramicin averaged 89.5%. Liquid chromatography with AAS detection has been shown to be a sensitive and highly specific technique for the determination of ionophores in general and maduramicin in particular.
Liquid Chromatographic Methods for Vitamins A and D in Multivitamin-Mineral Formulations
Authors: Beaulieu Normand , Curran Norman M , Gagné Charles , Gravelle Micheline , Lovering Edward G 
Published: February 2020

Abstract
Liquid chromatographic screening procedures have been developed for the estimation of vitamins A and D in multivitamin-mineral tablet, capsule, gelatin capsule, and syrup formulations. The procedure can be used for measuring vitamin A present as either retinyl acetate or retinyl palmitate, and also for measuring the contribution to total vitamin A activity from 13-cis retinyl esters. The retinyl esters and their isomers are resolved from each other and their oxidation products. Ergocalciferol and cholecalciferol are not resolved from each other but they are resolved from other vitamin D isomers and from vitamins A, E, and K and their degradation products. Both assays use a 3 μm amino column, with a mobile phase of hexane for vitamin A and 1% isopropanol in hexane for vitamin D. The precision of replicate injections for vitamins A and D is better than 1% and the recovery from spiked syrups is better than 98%. The coefficient of variation for both assay methods is about 5%. Twenty formulations were analyzed for vitamin A and 24 were analyzed for vitamin D.
Determination of Arsenic in Beer by Dry Ashing, Hydride Generation Atomic Absorption Spectroscopy
Authors: Cervera Ma Luisa , Navarro Ascensio , Montoro Rosa , Catala Ramon , Ybańez Nieves 
Published: February 2020

Abstract
A method has been developed for determination of arsenic in beer. Organic matter is destroyed by the dry-ashing technique, the ash is dissolved in HC1, and hydrides of arsenic are generated by addition of sodium borohydride prior to atomization in a flame-heated quartz cell and atomic absorption spectroscopy measurement. The analytical features of the method are detection limit 0.1 ng/g beer, precision 8%, and recovery 97 ± 7%. The arsenic contents of different brands from Spain and other European countries were analyzed. In all samples, the arsenic levels found were well below maximum levels allowed in Spanish legislation (100 ng/g). The quantities of arsenic in Spanish beers do not differ from those found in foreign beers. No differences were found between bottled and canned beers, and no correlation exists between metal content and original specific gravity of the beers.
Enzyme-Linked Immunosorbent Assay for Screening Aflatoxin B1 in Cottonseed Products and Mixed Feed: Collaborative Study
Authors: Park Douglas L , Miller Brinton M , Hart L Patrick , Yang George , McVey James , Page Samuel W , Pestka James , Brown Lois H 
Published: February 2020

Abstract
A joint AOAC/IUPAC (International Union of Pure and Applied Chemistry) interlaboratory study of an enzyme-linked immunosorbent screening assay (ELISA) for aflatoxins was conducted in laboratories in Canada, France, Japan, South Africa, Switzerland, The Netherlands, Tunisia, and the United States. Twenty-eight samples of raw and roasted peanuts, corn, whole cottonseed, cottonseed meal, ammoniated cottonseed meal, and poultry feed containing various quantities of natural aflatoxins and supplemented when appropriate with aflatoxin B1 were distributed to participating laboratories for testing. The assay is based on conjugation of pure aflatoxin B1 to an enzyme and the competition between this conjugate and (free) aflatoxins in the product for aflatoxin-specific antibodies coated onto microtiter well walls. After a wash step to remove all unbound aflatoxins, a substrate, added to each well, is catalyzed from a colorless to a green solution by any bound enzyme-conjugated aflatoxin Bf present. The intensity of the color decreases as the amount of free aflatoxin B1 in the product increases. Overall correlation was good between ELISA and thin-layer chromatographic (TLC) results for cottonseed products and mixed feed. Variable results were reported for corn and peanut product samples. Although some positive samples (&gt; 15 ng/g) of cottonseed products and mixed feed were reported to contain &lt; 15 ng/g by visual determination, a review of data for absorbance measurements showed that the contamination level was close to the ≥ 15 ng/g standard and would not have been reported as negative under routine screening. Variation in ELISA results may have been due to several factors such as: lack of homogeneity of the aflatoxin contamination in the samples (prestudy TLC analysis samples were collected randomly from a pool of subsamples), interferences that resulted from incomplete removal of hexane during the filtration step, and antibody strips at or past their expiration date. The ELISA method has been adopted official first action as a screening method to determine the presence or absence of aflatoxin B1 at a concentration of ≥ 15 ng/g in cottonseed products and mixed feed.
Determination of Acidic Herbicides and Related Compounds in Water and Soil by Capillary Gas Chromatography Using a Nitrogen-Phosphorus Detector
Authors: Ahmed Abdul W , Mallet Victorin N , Bertrand Michel J 
Published: February 2020

Abstract
Methods are described for the determination of acidic herbicides and related compounds in water and soil. Eight acidic herbicides and related compounds were extracted from water using either dichloromethane or an XAD-2 resin column. The acidic moieties were derivatized with 2-cyanoethyldimethyl(diethyl)aminosilane. The derivatized compounds were separated using capillary gas chromatography and quantitated using a nitrogen-phosphorus detector. Extraction from water using dichloromethane or an XAD-2 resin column resulted in recoveries &gt; 90% at 0.1 ppb with an average coefficient of variation (CV) of 6%. In soils extracted with aqueous acetonitrileacetic acid and partitioned into dichloromethane, recoveries at 500 ppb were &gt; 75% with an average CV of 3.3%. The methods are rapid and there are few interferences.
Spectrofluorometric Determination of Histamine in Wines and Other Alcoholic Beverages
Authors: Vidal-Carou M C , Izquierdo-Pulido M L , Mariné-Font A 
Published: February 2020

Abstract
The spectrofluorometric determination of histamine in wines, other alcoholic beverages, and vinegars is described. Histamine is extracted with n-butanol, transferred to hydrochloric acid, and subjected to a condensation reaction with o-phthalaldehyde (OPT). The method was tested for sensitivity (0.03 ppm limit of detection and 0.08 ppm limit of determination), precision (6.4% CV for a content of 1.25 ppm and 19.5% CV for a content of 0.25 ppm), accuracy (97.1%), recovery (90.6-96.9%), and lack of interference by histidine. The method can be applied to wine, must, beer, champagne, cider, vermouth, and vinegar with satisfactory results.
Direct Competitive Enzyme-Linked Immunosorbent Assay for Sulfamethazine Residues in Milk
Authors: Dixon-Holland Deborah E , Katz Stanley E 
Published: February 2020

Abstract
A direct competitive enzyme-linked immunosorbent assay (ELISA) is described for the detection and estimation of sulfamethazine residues in milk. Samples are cleaned up rapidly by acidifying and centrifuging the milk, adjusting the supernatant liquid to pH 7.0, and centrifuging again. The supernate is then assayed using set points to estimate sulfamethazine levels in the sample in the range of 1 ppb to 1 ppm. Multiple samples of milk can be screened in 1.5-2 h by this ELISA method.
Optimized Monier-Williams Method for Determination of Sulfites in Foods: Collaborative Study
Authors: Hillery Barbara R , Elkins Edgar R , Warner Charles R , Daniels Dan , Fazio Thomas 
Published: February 2020

Abstract
A collaborative study was conducted of the Food and Drug Administration (FDA)-optimized Monier-Williams method for determining sulfites in foods. Twenty-one industry and government laboratories participated in the study, which was jointly sponsored by the National Food Processors Association and FDA. Familiarization samples were shipped to each collaborator. Collaborators were permitted to proceed to the main study only after they demonstrated ability to perform the method to ensure that the study tested the performance of the method itself and not that of the individual laboratories. The study design involved 3 food matrixes (hominy, fruit juice, and protein [seafood]). Each matrix was prepared at 3 sulfite levels—the regulatory level, half the regulatory level, twice the regulatory level— and as a blank. All test samples were analyzed as blind duplicates, which gave each collaborator a total of 24 test portions. Collaborative recoveries gave a reproducibility (among-laboratories) coefficient of variation that ranged from 15.5 to 26.6% for sulfite determined as S02 by weight in the 3 foods at the 10 ppm level. The optimized Monier-Williams method has been approved interim official first action to replace the AOAC modified Monier-Williams method, 20.123-20.125.
Detection and Separation of Fenpropathrin, Flucythrinate, Fluvalinate, and PP 321 by Thin-Layer Chromatography
Authors: Khazanchi Rajesh , Handa Swadesh K 
Published: February 2020

Abstract
Four synthetic pyrethroids having α-cyano ester groups, i.e., fenpropathrin, flueythrinate, fluvalinate, and PP 321, are separated by thinlayer chromatography and detected by a new set of chromogenic reagents. Synthetic pyrethroids containing the α-cyano group react with sodium hydroxide to liberate cyanide which forms pink spots with o-dinitrobenzene and p-nitrobenzaldehyde. The detection limit is 0.1 μg and the method can be applied for identification and confirmation of these synthetic pyrethroids in vegetables.
Changing Pesticide Technology in Meat and Poultry Products
Authors: Ellis Richard L 
Published: February 2020

Abstract
In response to consumer concerns about pesticide residues in meat and poultry, a National Residue Program was introduced in the 1960s. Rapidly developing analytical methods and instrument capability resulted in a laboratory-based program of sufficient size and technical capability to quantitatively determine an increasing number of pesticides. In 1985, at the request of the Food Safety and Inspection Service, the National Academy of Sciences evaluated the program and recommended that more emphasis be placed on preventing residues and providing a higher degree of safety to consumers. In response, FSIS made a commitment to increase and improve capability to test for more residues, including pesticides, and to develop or purchase rapid test systems to facilitate the planned expansion of the National Residue Program. Such systems are now being evaluated and integrated into the program. Factors important for acceptability of rapid tests are reviewed in detail.