bluuebunny/crossref_metadata_2025 huggingface dataset:
Matrix Solid Phase Dispersion Isolation and Liquid Chromatographic Determination of Sulfadimethoxine in Catfish (Ictalurus punctatus) Muscle Tissue
Authors: Long Austin R , Hsieh Lily C , Malbrou Marsha S , Short Charles R , Barker Steven A
Published: February 2020

A method for the isolation and liquid chromatographic determination of sulfadimethoxine In catfish (Ictalurus punctatus) muscle tissue Is presented. Blank control and sulf adlmethox- Ine-fortlfled fish muscle tissue samples (0.5 g) were blended with octadecylsllyl (C18,40 /μm, 18% load, endcapped) derivatlzed silica packing material. A column made from the C18/ fish tissue blend was first washed with hexane (8 mL), following which the sulfadimethoxine was eluted with dlchloromethane (8 mL). The eluant contained sulfadimethoxine analyte that was free from Interfering compounds when analyzed by liquid chromatography with UV detection (photodlode array, 270 nm). Standard curves for sulfadimethoxine Isolated from fortified samples were linear (0.999 ± 0.001) with an average relative percentage recovery of 101.1 ± 4.2% for the concentration range (50, 100, 200,400, 800, and 1600 ng/g) examined using sulfamethoxazole as the Internal standard. The interassay variability was 10.7 ± 8.2% with an Intra-assay variability of 2.2%.
Automated Liquid Chromatographic Determination Of Aflatoxin Mi In Milk Using On-Line Dialysis For Sample Preparation
Authors: Th.Tuinstra Louis G.M , Kienhuis Paul G.M , Dols Peter
Published: February 2020

A procedure has been developed for the automated Isolation of aflatoxin M1 from decreamed milk. The method uses online stopped flow dialysis and subsequent trace enrichment on a reverse-phase column. After a back-flush to the analytical liquid chromatography column, aflatoxin M1 is determined with fluorescence detection. Fully automated analysis Is possible with reproducible dialysis recoveries above 50% (CV = 7.5%, n = 25 at the 50 ng/kg level) and determination levels of 20 ng/kg within 20 mln.
Sample Collection and Sample Preparation Techniques for Aflatoxin Determination in Whole Cottonseed
Authors: Park Douglas L , Rua Sam M , Paulson J H , Harder Dwight , Young Allan K
Published: February 2020

The present paper describes a comparative study between sampling devices used In the official sampling plan for Arizona cottonseed and a device that provides a smaller sampling size. The official sample must be greater than 30 lbs from at least ten 3 lb probes/cottonseed lot, not exceeding 100 tons. This Is accomplished using a Probe-A-Vac pneumatic or corkscrew sampler with a 3 in. diameter X 50 In. probe. The alternative sampling device evaluated In this study uses a modified shop-vac wet-dry vacuum with a 0.75 in. diameter X 100 in. probe. Ten 1 lb probes were taken for a total sample size of 10 lbs. Aflatoxin concentrations in cottonseed samples taken using both sampling probes at adjacent points throughout the lot were determined with an AOAC thin-layer chromatographic method (26.052-26.059, 14th Ed., 980.20AH, 15th Ed.). Mean total aflatoxin concentrations for Probe-AVac vs shop-vac samples from 39 lots (1987-1988 crop year) and 21 lots (1988-1989 crop year) were 76.6 vs 68.5 and 39.5 vs 30.7 µg/kg, respectively. Long staple cottonseed was sampled using a long staple trier (LS Trier), an alternative for which may be the shop-vac system. Mean total aflatoxin concentrations for LS Trier vs shop-vac for 7 lots (1988-1989 crop year) were 9.4 vs 5.1, µg/kg respectively. Also, an ultracentrlfugal mill has proven to be highly versatile for both denuding and grinding cottonseed to be tested under both laboratory and nonlaboratory situations.
Food and Drug Administration Pesticide Residue Monitoring of Foods: 1983-1986
Authors: Yess Norma J , Houston Marcia G , Gunderson Ellis L
Published: February 2020

Pesticide residues In foods are reported for the 4-year period 1982-1986 [fiscal years (FY) 83-86]. Results were summarized from the 2 complementary approaches that make up the Food and Drug Administration's (FDA) pesticide residue monitoring program. Under regulatory monitoring, which focuses on residues in raw agricultural commodities, a total of 49 055 samples (27 700 domestic and 21 355 import) that Included fresh fruits and vegetables, grains and grain products, milk and dairy products, seafoods, and a variety of processed foods were analyzed. No residues were found In 60 and 48% of the domestic and Import samples, respectively, compared with 55 and 44% in FY78-82. About 3% of the domestic and 5% of the import samples were violative. In FY78-82, about 3 and 7% were violative, respectively. The other FDA monitoring approach, the Total Diet Study, was revised in April 1982 to expand coverage of age/sex groups, use updated diets, and provide for analysis of individual foods. Results from monitoring under this modified approach and from regulatory monitoring continued to demonstrate that pesticide residues In the U.S. food supply were well below regulatory limits, and dietary Intakes were many times lower than the Acceptable Daily Intakes established by international agencies
A Study of Ten Toxins Associated with Paralytic Shellfish Poison Using Prechromatographic Oxidation and Liquid Chromatography with Fluorescence Detection
Authors: Lawrence James F , Ménard Cathie , Charbonneau Claudette F , Hall Sherwood
Published: February 2020

Ten paralytic shellfish toxins [saxltoxln, neosaxltoxin, B-1, B- 2, gonyautoxin 1, 2, and 3 (i.e., GTX-1, GTX-2, and GTX-3), C-1, C-2, and C-3] were oxidized at room temperature under mildly basic conditions with hydrogen peroxide or periodic acid. The products were then analyzed by liquid chromatography (LC). The N-1-hydroxylated toxins (neosaxltoxin, B-2, GTX-1, and C-3) formed fluorescent products after periodate oxidation at ca pH 8.7, but did not form fluorescent derivatives with peroxide oxidation. The non-N-1-hydroxylated toxins (saxltoxln, B-1, GTX-2, GTX-3, C-1, and C-2) formed highly fluorescent derivatives with both peroxide and periodate oxidations. Individual toxins produced mainly single fluorescent peaks by reverse-phase LC. However, all GTX toxins eluted with the same retention time. Also, C-1 and C-2 eluted together, as did neosaxltoxin and B-2. The non--N-1- hydroxylated toxins could be detected In quantities as low as 20-50 pg/lnjectlon, while the N-1-hydroxy analogues could be detected at levels as low as 100-500 pg/lnjectlon. UV absorption and fluorescence emission spectra were similar for the oxidation products of all toxins examined (max. 333 ± 2 nm absorption, 389 ± 4 nm fluorescence emission).
Capillary Gas Chromatographic Determination of Cyclohexanone and 2-Ethyl-l-Hexanol Leached from Solution Administration Set
Authors: Danielson James W
Published: February 2020

A capillary gas chromatographic method is described for the determination of cyclohexanone and 2-ethyl-1-hexanol leached from solution administration sets. A preliminary study was made of compounds leached from solution administration sets by 5% sodium bicarbonate solution (pH 8.1), 0.9% sodium chloride solution (pH 6.8), and water. Water was selected as the leaching solvent because similar quantities of the compounds were leached into water and into both types of parenteral solutions. The correlation coefficients were 0.99977 for cyclohexanone and 0.99974 for 2-ethyl-1- hexanol, and recoveries were good (93-94%). Five administration sets from each of 2 manufacturers were analyzed by this method. The amounts of cyclohexanone that were leached from the individual sets varied considerably; however, similar quantities were leached from sets of both manufacturers. 2-Ethyl-1-hexanol was also found in extracts from each of the sets analyzed.
Quantitation and Confirmation of Sulfamethazine Residues in Swine Muscle and Liver by LC and GC/MS
Authors: Carignan Germain , Carrier Karen
Published: February 2020

The present paper describes a liquid chromatographic (LC) method for purification of crude swine tissue extracts before gas chromatographic/mass spectrometric (GC/MS) quantitation and confirmation of sulfamethazine at low ppb levels. Fractions corresponding to sulfamethazine were collected, evaporated to dryness, ^methylated with diazomethane, concentrated, and analyzed by GC/MS. A mass spectrometer was set to selected ion monitoring (SIM) mode. Ions 233, 227, 228, and 92 m/z were detected. Ratio 227/233 m/z (sulfamethazine/internal standard, [pheny| 13C6] sulfamethazine) was used for quantitation, while ratios 228/227 and 92/ 227 m/z, respectively, were used for confirmation. Quantitation in spiked blank muscle tissue was tested from 100 to 1 ppb and found acceptable at all concentrations studied; coefficients of variation ranged from 4.9 to 14.4%. Similar results were obtained for liver tissue from 5 to 20 ppb; coefficients of variation ranged from 1.2 to 9.1 %.
Determination of MCPA, Bromoxynil, 2, 4-D, Trifluralin, Triallate, Picloram, and Diclofop-Methyl in Soil by GC-MS Using Selected Ion Monitoring
Authors: Bruns Gary W , Nelson Susan , Erickson Dennis G
Published: February 2020

A double space extraction procedure was developed to simultaneously determine neutral herbicides (trifluralin, dlclofop- methyl, and triallate) and acid herbicides (MCPA, 2,4-D, bromoxynil, and picloram) in soil. The method uses capillary column gas chromatography (GC) and mass spectrometry (MS) detection with a high degree of confidence in the interpretation of herbicides in many soil types to the 0.003 ppm level. Detection limits at these low levels are possible because extracts can be concentrated by a factor of 50 with few coextractlve interferences evident in the chromatography. Recovery data are excellent for both groups of herbicides (81.5-97.8%, average); relative standard deviations vary from 15-23% because of a larger response variation using GC/MS detection.
Anodic Polarographic Determination of Acetylenic Hypnotics Ethinamate and Methylpentynol Carbamate in Dosage Forms
Authors: Belal F
Published: February 2020

The polarographic behavior of ethinamate and methylpentynol carbamate was studied. Both drugs developed anodic waves in a supporting electrolyte composed of 1M sodium hydroxide and methanol (9 + 1). The relation between the limiting current and the concentration was rectilinear over the range 2.5 X 10-5-2.5 X 10-4M for both drugs. The characteristics of the waves were studied, and a model of the electrode reaction was suggested. The proposed method was successfully applied to the determination of the 2 drugs in their dosage forms, and the results were in agreement with those obtained with published methods.
Chemical Derivatization Analysis of Pesticide Residues. Part XI. An Improved Method for the Determination and Confirmation of Acidic Herbicides in Water
Authors: Lee Hing-Biu , Peart Thomas E , Carron John M , Tse Hung
Published: February 2020

A procedure for the determination and confirmation of acidic herbicides In water Is described. This method is applicable to 13 commonly used herbicides, including the monochlorinated ones, at μg/L and sub-μg/L levels. The water sample is acidified to pH < 2 and extracted by dichloromethane. The herbicides are converted into their pentafluorobenzyl (PFB) derivatives and the products are cleaned up on a silica gel column. A gel permeation cleanup using a Bio-Beads S-X3 column is included to remove the PFB esters of fatty acids, which are the major Interferences in the final analysis using electron capture detection (ECD). Confirmation of herbicides employing electron Impact and negative ion chemical lonlzatlon/ mass spectrometry (NICI/MS) is discussed and applied to river water samples. The mean recoveries of herbicides for water samples fortified at 1 and 0.1 μg/L range from 45 to over 90%. The detection limit of herbicides in natural water samples is 0.05 μg/L with ECD and 0.02 μg/L with NICI/MS.
Separation and Determination of Diesel Contaminants in Various Fish Products by Capillary Gas Chromatography
Authors: Newton J M , Rothman Barry S , Walker F Ann
Published: February 2020

A semiquantitative capillary column gas chromatographic method Is described for the determination of diesel fuel contamination in various canned seafood products. The diesel contaminants are separated from the fish sample by steam distillation, with little carry-over of interfering intrinsic materials such as fish oils. The diesel fuel is extracted from the condensate with n-hexane, and the extract is analyzed on an SPB-1 fused silica capillary column. The efficiency of recovery of diesel fuel added to canned seafood at levels of 40-400 ppt ranged from 72 to 102%. With the additional step of concentrating the hexane extract, the sensitivity of this procedure may be increased at least 10-fold. This procedure can detect the differences among diesel fuel grades No. 1,2, and 5, and variations within diesel grade No. 2, and thus may be useful in determining the type of petroleum contaminants present in various canned fish products.
Determination of Methyl 2-Benzimidazolecarbamate
in Blueberries by Competitive Inhibition Enzyme Immunoassay
Authors: Bushway Rodney J , Ugabalasooriar Jasotha , Perkins Lewis B , Harrison Robert O , Young Barbara E S , Ferguson Bruce S
Published: February 2020

A polyclonal enzyme Immunoassay (EIA) method was developed that will quantitate methyl 2- benzlmidazolecarbamate (MBC), the degradation product of benomyl, In blueberries. The entire analysis Is completed within 25 min, and up to 8 samples can be analyzed simultaneously with a detection limit of 18 ppb. The assay response was linear from 0.69 to 22 ppb MBC. Cross-reactivity was confined to the benzimidazole and dicarboxlm- Ide type pesticides. Intra-assay percent coefficients of variation (% CVs) ranged from 3.4 to 18.4 for the standards, and from 3.2 to 20.6 for the samples. Interassay % CVs varied from 7.5 to 22.3 for the standards, and from 7.5 to 22.0 for the samples. Correlation coefficient between immunoassay and liquid chromatography was 0.87 for the methanol extract and 0.98 for the methylene chloride partition of the methanol extract containing 100 mL 1% sodium chloride. None of the 40 field samples analyzed approached the tolerance of 15 ppm (mean of 20 positive samples was 55 ppb). The ability of the EIA to monitor MBC easily and Inexpensively at concentrations far below the tolerance has major implications for current dietary risk assessment methods.
Matrix Solid-Phase Dispersion Extraction and Liquid Chromatographic Determination of Nicarbazin in Chicken Tissue
Authors: Schenck Frank J , Barker Steven A , Long Austin R
Published: February 2020

This method outlines the necessary steps for the isolation and determination of the drug nicarbazin in chicken liver and muscle tissue. Tissue samples were blended with octadecylsilyl-derivatized silica packing material (C18). A column made from the C18-tissue matrix is first washed with hexane, and then the 4,4-dinitrocarbanilide (DNC) portion of the nicarbazin complex is eluted with acetonitrile. After further cleanup using alumina cartridge chromatography, DNC is determined by reversed-phase liquid chromatography with UV detection at 340 nm. Recoveries based on DNC were 95.8 and 83.7% from liver and muscle tissues, respectively. This method and a classical ethyl acetate extraction method gave comparable results on 4 chicken liver and 3 muscle samples that contained incurred nicarbazin residues. C18 sorbents from different manufacturers as well as lipophilic sorbents other than ds were also studied. The proposed extraction and cleanup procedure requires less than 30 mL solvent, fewer sample manipulations, and does not require solvent partitioning or backwashing of extracts. This combination of characteristics makes this method more attractive than classical isolation procedures for nicarbazin.
Bleaching of Methylene Blue as an Index of Lipoxygenase Activity
Authors: Toyosaki Toshiyuki
Published: February 2020

An assay of lipoxygenase activity was developed that depends on measurements of the time needed for the bleaching of methylene blue to begin. This time was inversely related to the level of lipoxygenase activity (y = 114.5132 - 0.0132x; r= -0.99); it was not affected by the concentration of methylene blue, linoleic acid, or hydroperoxide. Lipoxygenase activity can be calculated from the time needed for the bleaching of methylene blue to begin.
Liquid Chromatographic Confirmatory Method for Five Sulfonamides in Salmon Muscle Tissue by Matrix Solid-Phase Dispersion
Authors: Reimer Gerry J , Suarez Agripina
Published: February 2020

A reversed-phase (C18) liquid chromatographic (LC) method was developed for the analysis of 5 sulfonamides (sulfadiazine [SDZ], sulfamerazine [SMRZ], sulfamethazine [SMTZ], sulfadimethoxine [SDMX], and sulfapyridine [SP]) in salmon muscle tissue. Spiked tissue samples were extracted by matrix solid-phase dispersion. The LC mobile phase gradient consisted of acetonitrile-aqueous 0.01M ammonium acetate (pH 5.5). The potentiators trimethoprim and ormetoprim were also resolved with this chromatographic system. The method detection limits at the 99% confidence level were 48,66,228, and 150 ppb for SP, SMRZ, SMTZ, and SDMX, respectively, and approximately 100 ppb for SDZ. The average percent recoveries of analytes from salmon muscle tissue were 66,66,71,82, and 75% for SDZ, SP, SMRZ, SMTZ, and SDMX, respectively
Survey of Bottled Drinking Water Sold in Canada. Part 2. Selected Volatile Organic Compounds
Authors: Page B Denis , Conacher Henry B S , Salminen John , Nixon Gerald R , Riedel Gunther , Mori Brian , Gagnon Jacques , Brousseau Robert
Published: February 2020

Selected volatile organic compound (VOC) contaminants were determined in 182 samples of retail bottled waters purchased in Canada. Samples included spring water (86) packaged in containers of polyethylene or in smaller containers of transparent plastic or glass, mineral water (61) packaged only in transparent plastic or glass, and miscellaneous bottled waters (35). Analyses were performed by 3 laboratories, each using headspace sampling and capillary gas chromatography with either mass spectrometric (1 laboratory) or flame ionization detection with mass spectrometric confirmation, if required (2 laboratories). Benzene, the contaminant of primary interest, was detected in only 1 of the 182 samples at 2 μg/kg. Other VOC contaminants detected (number of positive samples, average, and range of positives in μg/kg) included toluene (20,6.92,0.5-63), cyclohexane (23, 39.2,3-108), chloroform (12,25.8,3.7-70), and dichloromethane (4,59,22-97). Cyclohexane was found in the plastic and as a migrant from the plastic in 20 samples of spring water, but it was found in only 1 of 61 mineral water samples analyzed at only 3 μg/kg. Chloroform was found almost exclusively in samples that could have been obtained from public water supplies. It was not found in mineral water samples, but it was found in 1 spring water sample at 3.7 μg/kg. The source of the toluene contamination was not known. Other VOCs detected include ethanol and limonene, associated
U.S. Food and Drug Administration Survey of Methyl Mercury in Canned Tuna
Authors: Yess Norma J
Published: February 2020

Methyl mercury was determined by the U.S. Food and Drug Administration (FDA) in 220 samples of canned tuna collected in 1991. Samples were chosen to represent different styles, colors, and packs as available. Emphasis was placed on waterpacked tuna, small can size, and the highest-volume brand names. The average methyl mercury (expressed as Hg) found for the 220 samples was 0.17 ppm; the range was <0.10-0.75 ppm. Statistically, a significantly higher level of methyl mercury was found in solid white and chunk white tuna than was found in chunk light and chunk tuna. Methyl mercury level was not related to can size. None of the 220 samples had methyl mercury levels that exceeded the 1 ppm FDA action level.
Extraction of Light Filth from Oriental Fish Products Containing Spice: Collaborative Study
Authors: Glaze Larry E ,   Collaborators:, Davis W , Floyd D M , Graham C R , Nagy J K , Olson R E , Palau J , Spurlock L F , Sumner W A , VanVelzen W T
Published: February 2020

A collaborative study was conducted to validate a new method for the extraction of light filth from oriental fish products containing spice. A100 g test portion is digested by boiling in a mixture of HCI, Igepal DM-710, and CO-730. Light filth is isolated by wetsieving on a No. 230 plain-weave sieve with Tergitol, deaeration boiling in 40% isopropanol, and extracting with mineral oil-heptane (85 + 15) and 40% isopropanol in a Wildman trap flask. Three spiking levels for rat hairs and insect fragments were used in the study. For rat hairs, recoveries at the low, medium, and high levels averaged 80.0,71.6, and 88.0%, respectively. Recoveries of insect fragments for low, medium, and high levels averaged 87.8,83.7, and 89.4%, respectively. The method was adopted first action by AOAC International.
Sugars, Alcohols, and Hydroxymethylfurfural in Authentic Varietal and Commercial Grape Juices
Authors: Fuleki Tibor , Pelayo Estela
Published: February 2020

The quantity of fructose, glucose, and sucrose present in authentic varietal grape juices produced by cold and/or hot pressing from 56 cultivars was determined by liquid chromatography for the 1988 and 1989 seasons. The concentration of fructose, glucose, and sucrose and the fructose:glucose ratio ranged from 5.97 to 10.92, 4.91 to 9.99, trace to 1.04 g/100 mL, and 0.92 to 1.41, respectively. Sorbitol and hydroxymethylfurfural were not detected in the authentic grape juices. Genotype had no significant effect on the fructose and glucose contents. The labrusca-type cultivar group was significantly higher in the sucrose concentration and fructose.glucose ratio than either the vinifera or the French hybrid groups. The pressing method had no significant effect on the sugar composition. The glucose, fructose, total sugar, and total soluble solids contents were significantly higher in the juices from the warmer and sunnier 1988 season. The total sugar contents correlated highly with total soluble solids, but the latter averaged 1.81 units more than the former. Most commercial grape juices had a composition similar to that of the authentic juices, except that they had only traces of sucrose. Also, most commercial grape juices contained measurable quantities of ethanol, glycerol, and hydroxymethylfurfural.
Determination of Organic Pollutants in Reagent Water by Liquid-Solid Extraction Followed by Supercritical Fluid Elution
Authors: Tang Peter H , Ho James S , Eichelberger James W
Published: February 2020

A selected group of polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides, and phthalate esters in reagent water containing no particulate matter were separated and identified by liquid-solid extraction and supercritical fluid extraction (SFE). The water sample is first passed through a cartridge or disk containing a solid matrix coated with a chemically bonded C18 organic phase capable of extracting those organic compounds. The cartridge or the disk is then eluted with supercritical carbon dioxide to remove the compounds from the sorbent. Finally, the extract is injected into a capillary column gas chromatographic/quadruple mass spectrometric system. The precisions, percent recoveries of analytes using solvent elution, and percent recoveries using SFE are compared. The total analysis time is greatly reduced by using disk extraction and SFE in place of cartridge extraction and liquid-solvent elution. In addition, the waste solvent generated was minimized by using SFE.
Study of the Reproducibility Characteristics of a Liquid Chromatographic Method for the Determination of Fumonisins B1 and B2 in Corn: IUPAC Collaborative Study
Authors: Thiel Pieter G , Sydenham Eric W , Shephard Gordon S , Van Schalkwyk Dirk J ,   Participants:, Casper H H , Gilbert J , Ishii K , Norred W P , Ross P F , Stack M E , Stockenström S , Trinder D W , Egmond HP. van , Viljoen C C , Visconti A
Published: February 2020

An interlaboratory study of the reproducibility characteristics of a liquid chromatographic method for the determination of fumonisins B1 and B2 in corn was conducted in 11 laboratories in the United States, South Africa, Italy, Japan, United Kingdom, and The Netherlands. Each laboratory was supplied with 12 coded, blind duplicates of 6 samples of naturally contaminated corn containing different amounts of fumonisins B1 and B2 . Samples are extracted with methanol-water (3 + 1), extracts are centrifuged, and supernatants are cleaned up on strong-anion-exchange cartridges, which were supplied to participants. Solutions are derivatized with o-phthaldialdehyde, and individual fumonisins are determined by reversed-phase liquid chromatography with fluorescence detection. Quantitation is by comparison with the supplied fumonisin standards. The within-laboratory repeatability was determined by statistical analysis of data after exclusion of outliers. Relative standard deviations for within-laboratory repeatability varied from 7.7 to 25.5% for fumonisin B1 at concentrations between 200 and 2000 ng/g and from 12.5 to 36.8% for fumonisin B2 at concentrations between 70 and 740 ng/g. Relative standard deviations for betweenlaboratory reproducibility varied from 18.0 to 26.7% for fumonisin B1 and from 28.0 to 45.6% for fumonisin B2 at the concentrations mentioned above. These measures of variability indicate that the method is suitable for adoption as an official method provided that the accuracy characteristics are verified collaboratively.
Adsorptive-Stripping Determination of Sulfamethazine in Milk
Authors: Ng Wing-Yan , Wong Siu-Kay
Published: February 2020

A cleanup procedure is described for the determination of sulfamethazine in milk. The residue is diazotized and coupled with 1-naphthol. The diazotized sulfamethazine (SMZ) is accumulated on a mercury electrode by electrochemical adsorption and is then stripped cathodically. This method determines SMZ quantitatively at low parts-per-billion levels.
Improved Method for Determination of Sulfites in Shrimp
Authors: Armentia-Alvarez Arantza , Peña-Egedo M Jesus , Garcia-Moreno Concepcion
Published: February 2020

A method for the determination of sulfites in shrimp developed by Kim and Kim and modified by Paino-Campa et al. for sausages has been further modified. Total sulfites are extracted by initially adding aluminum oxide to the sample and using an extraction solution at pH 12. In the reproducibility assays, coefficients of variation (CVs) were 4.8% for free sulfite and 7.8% for total sulfite in the edible part of the shrimp. In the inedible part, CVs were 7.5% and 8.9% for free and total sulfite, respectively. Mean recovery was 87.8% for the edible part and 84.4% for the inedible part of the shrimp. The method was compared with the optimized Monier- Williams method. The results obtained with both methods for determination of total SO2 in the edible part of the shrimp did not show significant differences (P= 0.05).
Determination of Traces of Silicone Defoamer in Fruit Juices by Solvent Extraction/Atomic Absorption Spectroscopy
Authors: Gooch Emmett G
Published: February 2020

Silicone defoamers are used to control foam during the processing of fruit juices. Residual silicones in fruit juices can be separated from the naturally occurring siliceous materials in fruit products and selectively recovered by solvent extraction, after suitable pretreatment. The recovered silicone is measured by atomic absorption spectroscopy. Silicone concentrations as low as about 1 ppm can be measured. The juices are accurately spiked for recovery studies by the addition of silicone dispersed in D-sorbitol.
Microbiological Screening Method for Indication of Irradiation of Spices and Herbs: A BCR Collaborative Study
Authors: Wirtanen Gun , Sjöberg Anna-Maija , Boisen Flemming , Alanko Timo ,   Collaborators:, Aureli Paolo , Betts Roy , Boisen Flemming , Copin Marie-Pierre , Guerzoni M Elisabetta , Hammerton Kerie M , Savolainen Jouko , Skovgaard Niels
Published: February 2020

A BCR1 collaborative study was conducted with a microbiological screening method based on the combined use of the direct epifluorescent filter technique (DEFT) and the conventional aerobic plate count method (APC) for detection of irradiation of spices and herbs. Collaborative samples of whole allspice, whole and powdered black peppers, whole white pepper, paprika powder, cut basil, cut marjoram, and crushed cardamom irradiated with doses of 0, 5, and 10 kGy were analyzed by 8 laboratories. The total number of the collaborative samples, with arbitrarily labeled codes, was 192. The percentage of acceptable results was 95.5%. The identification of irradiated from nonirradiated spices and herbs was analyzed statistically by using explorative techniques. The average values of the differences between DEFr and APC in samples irradiated with doses of 5 and 10 kGy were 5.1 and 6.1 logarithmic units, respectively. The differences between DEFT and APC generally increased to at least 3.5 logarithmic units, whereas the difference in the case of unirradiiated spices was insignificant. However, conclusive evidence of irradiation relies on the knowledge that the sample was not fumigated or heat treated. The reproducibility relative standard deviations for the differences were 12.3,19.9, and 20.7% with the closes of 10 and 5 kGy and for unirradiated samples, respectively, indicating acceptable variabilities among laboratories. Received
Comparison of Texas Liquid Sampler with Missouri Bottle for Sampling Liquid Fertilizers: Collaborative Study
Authors: Latimer George W ,   Collaborators:, Comstock J , Dubberly D , Jessup T , McCurry C , Ritz R , Terry D
Published: February 2020

Six laboratories participated in a collaborative study designed to qualify the Texas liquid sampling tube as a device for sampling liquid fertilizers. The Texas sampler is a polyethylene tube with a stainless steel check valve on one end. The tube, which is threaded so that it can be expanded in length, enables acquisition of a uniform profile across a liquid sample. The 6 collaborators sampled 33 loads of fertilizer, 8 of which were slurries, using both the Texas tube and the Missouri bottle (AOAC 969.01). The resulting subsamples were analyzed for total nitrogen, available phosphorus, and soluble potash. Analysis of the data showed no significant (p < 0.05) difference in results. This sampling procedure, using the Texas liquid sampler, was adopted first action by AOAC International as a suitable means of sampling liquid fertilizers.
Comparison of MICRO-ID Listeria Method with Conventional Biochemical Methods for Identification of Listeria Isolated From Food and Environmental Samples: Collaborative Study
Authors: Higgins Don L , Robison Barbara J ,   Collaborators:, Bailey S , Hagen C , Higgins D , Jankow D , Jost K , Kallay K , Kulhanek C , Madden J , Matushek M , Okolo C , Pratt M , Sloan E , Stone J , Tuncan E , Weagent S , Weatherington J
Published: February 2020

Fourteen laboratories participated in a collaborative study to evaluate the ability of the MICRO-ID Listeria identification method to correctly identify Listeria isolated from food and environmental sources. Each collaborator received 60 isolates consisting of 51 Listeria and 9 non-Listeria cultures. All isolates were identified by conventional biochemical analyses in the principal laboratory. Cultures were checked for purity by Gram staining and examined for oxidase and catalase activities. Only Gram positive, oxidase negative, catalase positive cultures were tested with the method. Colonies from trypticase soy agar with 0.6% yeast extract were suspended in 4.6 ml_ physiological saline to a MacFarland No. 1 turbidity standard and used to inoculate the test strip. In addition, the hemolytic reaction of each isolate was determined by using the Christie-Atkins-Munch-Peterson (CAMP) test and by stabbing sheep blood agar. Identification of Listeria is based on the octal code obtained from the strip and the hemolytic reaction of the isolate. The MICRO-ID Listeria method agreed with conventional biochemical identification for 98.0% of L. monocytogenes, 77.1% of L. seeligeri, 98.0% of L ivanovii, 96.4% of L. grayi/L. murrayi, 73.9% of L. welshimeri, and 100% of L innocua isolates. A large percentage of errors in identification of the L. seeligeri and L ivanovii cultures was caused by inaccurate reading of the CAMP and hemolysis tests rather than errors in the test strip. The method was adopted first action by AOAC International.
Enzymatic-Gravimetric Determination in Foods of Dietary Fiber as Sum of Insoluble and Soluble Fiber Fractions: Summary of Collaborative Study
Authors: Mongeau Roger , Brassard Rene
Published: February 2020

A collaborative study was conducted on an enzymatic- gravimetric method for determination of total dietary fiber in foods, in which soluble fiber and insoluble fiber are determined separately. Ten collaborators analyzed blind duplicate test samples from 5 food products: turnip, wheat bran, beans canned with tomato sauce, rice, and whole wheat bread. Repeatability and reproducibility relative standard deviations ranged from 1.48 to 14.73% and from 4.13 to 17.94%, respectively. The method was adopted first action by AOAC International.
Determination of Roxarsone in Feeds Using Solid Phase Extraction and Liquid Chromatography With Ultraviolet Detection
Authors: Sapp Robert E , Davidson Sandra
Published: February 2020

A method is presented for detection and quantitation of Roxarsone in poultry feed by liquid chromatography. The drug is extracted by phosphate buffer and determined by solid phase extraction and reversed-phase liquid chromatography. Recoveries of the sample spikes and fortified field samples agree closely with those obtained by the standard spectrophotometric method.
Evaluation of New Flame Photometric Instrumentation to Meet Requirements of AOAC Official Method for Potassium in Fertilizers
Authors: Newlon Natalie
Published: February 2020

AOAC Official Method 983.02 for potassium in fertilizers contains instrument performance criteria. The Bran & Luebbe Flame Photometer 410 with a TRAACS 800 was evaluated by this method. Noise, drift, carryover, and precision were investigated. Drift and noise were well below the specifications. Carryover was essentially zero. The overall performance of the system based on National Institute of Standards and Technology standards and quality control samples showed an average bias of 0.10%, which is within the method specifications; the absolute values of differences were 0.166% for the citrate extraction and 0.063 and 0.171%, respectively, for the oxalate extractions. The method states that the average bias should be <0.1, and the absolute value of differences should be <0.4. Overall, the system passed all the performance criteria specified in the method.
Liquid Chromatographic Determination of Aflatoxin M1 in Milk Powder Using Immunoaffinity Columns for Cleanup: Interlaboratory Study
Authors: Tuinstra Louis G M Th , Roos Arie H , Van Trijp John M P ,   Collaborators:, Burdaspal P A , Declercq B , Dutton M F , Donahue K F , Fremy J M , Pittet A , Rasmussen G , Rutschmann M A , Sharman M , Stubblefield R D , Toyoda M , Egmond van H P , Bedem J van den , Renterghem R van , Wei Yau-Huei
Published: February 2020

A liquid chromatographic method for determining low aflatoxin M1 concentrations in milk was evaluated in an International Dairy Federation (IDF) interlaboratory study. The study involved 16 participants from 11 countries. The method, chosen after a comparison of several methods by a preparatory group, uses an immunoaffinity column for cleanup. As the sample passes through the column, antibodies selectively bind with aflatoxin M1 (antigen) present and form an antibody-antigen complex. All other components of the sample matrix are washed off the column with water. Then, aflatoxin M1 is eluted from the column with acetonitrile, which is collected. Final determination is carried out by reversed-phase liquid chromatography with fluorescence detection. Over the tested range (80-600 ng aflatoxin M1/kg milk powder), an RSDR ranging from 11 to 23% was obtained by analyzing 24 samples (blind duplicates), 2 samples of which were blanks.
ColiComplete® Substrate-Supporting Disc Method for Confirmed Detection of Total Coliforms and Escherichia coli in All Foods: Comparative Study
Authors: Feldsine Philip T , Falbo-Nelson Maria T , Hustead David L
Published: February 2020

The ColiComplete® substrate-supporting disc (SSD) method for simultaneous confirmed total coliform count and Escherichia coli determination in all foods was compared with the AOAC most probable number (MPN) methods 966.23 and 966.24. In this comparative study, 20 water and food types were analyzed; 7 of these foods were naturally contaminated with coliform bacteria, 6 food types were naturally contaminated with E. coli, and the remaining foods were inoculated with coliform bacteria and/or E. coli. Data were analyzed separately for total coliform bacteria and for E. coli. Mean log MPN counts were determined by the SSD method and the appropriate AOAC MPN procedure. Results were then analyzed for mean log MPN differences and variance, according to methods described by AOAC INTERNATIONAL Results for both total conforms and E. coli indicate that the SSD method is equivalent to or better than AOAC MPN methods 966.23 and 966.24.
Determination of Aldicarb, Aldicarb Sulfoxide, and Aldicarb Sulfone in Oranges by Simple Gas–Liquid Chromatography with Nitrogen–Phosphorus Detection
Authors: Albelda Carmen , Picó Yolanda , Font G , Mañes Jordí
Published: February 2020

A reversed-phase liquid chromatographic method, using an acetonitrile–water gradient mobile phase, and a gas-liquid chromatographic method with nitrogen–phosphorus and flame photometric detection were compared for simultaneous and separate determinations of trace quantities of aldicarb and its metabolites aldicarb sulfone and aldicarb sulfoxide. One hundred gram samples of fortified oranges were extracted with water–acetone, water-acetonitrile, or water–methanol, and the extracts were partitioned with methylene chloride. Partitioning with other organic solvents such as chloroform, ethyl acetate, or methyl isobutyl ketone was also investigated. When performed under optimal conditions, the procedure has detection limits of 0.4, 0.8, and 0.4 ppb for aldicarb, aldicarb sulfoxide, and aldicarb sulfone, respectively. Recoveries at fortification levels of 4,20, and 80 ppb ranged from 75 to 90%. Coefficients of variation ranged from 8 to 10%.
Rapid, Sensitive, Iron-Based Spectrophotometric Methods for Determination of Peroxide Values of Food Lipids
Authors: Shantha Nalur C , Decker Eric A
Published: February 2020

The official International Dairy Federation method for determination of the peroxide value of anhydrous milk fat was extended to poultry, meat, fish, and vegetable oils. The ferrous oxidation–xylenol orange method for determination of peroxide values of liposomes and lipoproteins was modified to make it simpler and more rapid. These 2 spectro-photometric methods were used successfully to determine the peroxide values of beef, chicken, butter, fish, and vegetable products. The results in most cases were consistent with those obtained by using the AOAC Official Method. The spectro-photometric methods have an assay time of less than 10 min, require ≤0.3 g fat, and are capable of determining peroxide values as low as 0.1 mequiv/kg of sample.
Simultaneous Screening of Fumonisin B1, Aflatoxin B1, and Zearalenone by Line Immunoblot: A Computer-Assisted Multianalyte Assay System
Authors: Abouzied Mohamed M , Pestka James J
Published: February 2020

A line immunoblot assay was developed for the simultaneous screening of fumonisin B1 (FB1), aflatoxin B1 (AFB1), and zearalenone (ZEA). Monoclonal antibodies for each of these toxins were immobilized as multiple lines on nitrocellulose membrane strips and sectored into hydrophobic compartments to minimize use of reagents. A modified enzyme-linked immunosorbent assay was conducted whereby free mycotoxins and horseradish peroxidase-labeled mycotoxins competed for binding to the nitrocellulose-bound antibodies. Color intensity of lines formed by a precipitating substrate was inversely related to mycotoxin concentration. Detection limits for the individual mycotoxins, as determined by visually comparing the color intensity of positive strips to negative controls, were 500, 0.5, and 3 ng/mL for FB1, AB1, and ZEA, respectively. Line density was quantitatively assessed also by using a camera, video monitor, and microcomputer equipped with a video-digitizing board. The assay could be used to determine range values for the various mycotoxins in extracts of spiked corn in less than 30 min, and values could be recorded on the microcomputer hard disk. This combination of line immunoblot assay and image analysis, termed computer-assisted multianalyte assay system, should be applicable to the simultaneous screening of multiple mycotoxins and other agricultural residues in food.
Enumeration of Total Bacteria in Raw and Pasteurized Milk by Reflectance Colorimetry: Collaborative Study
Authors: Richardson Gary H , Yuan James T C , Sisson Donald V , Stokes Barry O
Published: February 2020

Seven out of 9 laboratories completed a collaborative study comparing a reflectance colorimetric (RC) bioactivity monitor (Omnispec™ 4000) method to the standard plate count (SPC) method for estimation of total bacteria in raw and homogenized pasteurized milk. Each laboratory analyzed 12 different samples by the SPC method and 24 samples (12 blind duplicates) by the RC method. For the RC method RSDr was 1.7%, and RSDR was 4.5%. RSDR for the SPC method was 20.8%. The method was adopted first action by AOAC INTERNATIONAL.
Determination of Deoxynivalenol in 1991 U.S. Winter and Spring Wheat by High-Performance Thin-Layer Chromatography
Authors: Fernandez Cecilia , Stack Michael E , Musser Steven M
Published: February 2020

A thin-layer chromatographic (TLC) method was modified for determination of deoxynivalenol (DON) in 1991 U.S. winter and spring wheat. After extraction with acetonitrile-water (84 +16) and cleanup on a charcoal-alumina-Celite (7 + 5 + 3) column, acetonitrile was used instead of ethyl ace- tate to transfer the concentrated extract containing DON. After the extract was evaporated to dryness, the residue was dissolved in methanol and an ali- quot was spotted on a high-performance TLC plate. After development with chloroform-acetone-2- propanol (8 + 1 + 1), the plates were sprayed with aluminum chloride solution and heated; DON was quantitated by fluorodensitometry. Average recov- eries of DON added to duplicate test portions of wheat at 200,400, and 800 ng/g were 83,82, and 72%, respectively. The detection limit was 40 ng/g. The method was applied to 81 test samples of spring and winter wheat. The wheat contained DON levels that ranged from nondetectable to 9330 ng/g (average 1570 ng/g). The results indicate that DON levels were higher in wheat from Missouri, North Dakota, and Tennessee than in wheat from 7 other states. The identity of DON, which was isolated from 21 of the extracts by preparatory TLC, was confirmed by gas chromatography/mass spec- trometry in all 21 test samples.
Determination of the Iodine Value of Oils and Fats: Summary of Collaborative Study
Authors: Firestone David
Published: February 2020

Two collaborative studies were conducted using the Wijs method for determining the iodine value in a wide range of vegetable and animal oils and fats. The results obtained when using carbon tetrachlo-ride were compared to those obtained when using a substitute solvent mixture of cyclohexane and glacial acetic acid. The values reported for the iodine values indicate that the cyclohexane and acetic acid mixture can be used in place of carbon tetrachloride without loss of precision. The method has been adopted first action by AOAC INTERNATIONAL as an IUPAC/AOCS/AOAC method.
Determination of Total Dietary Fiber in Foods and Products with Little or No Starch, Nonenzymatic-Gravimetric Method: Collaborative Study
Authors: Li Betty W , Cardozo Maria S
Published: February 2020

A collaborative study was conducted to validate a nonenzymatic-gravimetric method for the determination of total dietary fiber (TDF) of samples containing little or no starch such as most fruits, and vegetables and many purified polysaccharides. This simple procedure involves suspension of freeze-dried, ground samples in deionized water and incubation at 37°C for 90 min, followed by pre-cipitation with 4 volumes of 95% ethanol. The weight of the dilute alcohol-insoluble residues after correcting for crude protein and ash corresponds to the TDF content of the sample. Six samples in blind duplicate (apples, apricots, cabbage, carrots, onions, and soy fiber) were sent with Celite to 10 laboratories. The reproducibility relative standard deviation (RSDr) of the TDF values for 9 laboratories ranged from 2.92 to 6.25%. The repeatability standard deviation (RSDr) for the 9 laboratories ranged from 1.50 to 2.70%. The method has been adopted first action by AOAC INTERNATIONAL.
Simple and Rapid Determination of Phytase Activity
Authors: Engelen Adrianus J , Van Der Heeft Fred C , Randsdorp Peter H G , Smtt Ed L C
Published: February 2020

A simple and rapid method is described for determining the enzymatic activity of microbial phytase. The method is based on the determination of inorganic orthophosphate released on hydrolysis of sodium phytate at pH 5.5.
Comparison of Direct Extraction and AOAC Official Methods for Available P2O5 in Fertilizers: Collaborative Study
Authors: Gliksman Joseph E
Published: February 2020

Fifteen fertilizer samples were sent to 13 laboratories for determination of available P2O5. Eleven laboratories, including author's laboratory, completed the analyses. Each sample was analyzed twice for available P2O5 by the new direct extraction method, and by either of the AOAC Official Methods using direct or indirect extraction. Results were favorable for the new direct extraction method even though the range and types of samples were highly variable. The direct extraction method was adopted first action by AOAC INTERNATIONAL.
Determination of Dephosphate Bromofenofos in Milk by Liquid Chromatography with Electrochemical Detection
Authors: Takeba Kazue , Itoh Takeshi , Matsumoto Masao , Nakazawa Hiroyuki
Published: February 2020

A sensitive, specific method for the determination of dephosphate bromofenofos (DBFF) in milk by liquid chromatography (LC) with electrochemical detection is described. DBFF, the only metabolite of bromofenofos (BFF, a fasciolicide), was extracted from milk by liquid–liquid partition with acetone, acetonitrile, and dichloromethane and purified by using a C18 cartridge. The compound was separated from the matrix peaks by reversed-phase LC and detected by dual-electrode coulometric detection on a Kaseisorb LC ODS-300-5 (250 × 4.6 mm id, 5 μm) column. The mobile phase was acetonitrile–0.05M potassium dihydrogen phosphate (55 + 45, v/v) at pH 3.0. The flow rate was 1 mL/min at 40°C. The applied potentials of detectors 1 and 2 were maintained at 0.30 and 0.45 V, respectively. Average recoveries (n = 5) of DBFF from milk spiked at 1 and 10 ng/mL were 73.1 and 82.7%, respectively; and coefficients of variation were 8.4 and 2.8%, respectively. The detection limit of DBFF in milk was 0.2 ng/mL. Fifty-nine raw and 181 commercial milks were analyzed. DBFF was detected in 4 raw milks (0.2–1.5 ng/mL; average, 0.6 ng/mL) and in 3 normal liquid commercial milks (0.3–0.7 ng/mL; average, 0.5 ng/mL). The identity of DBFF from milk was confirmed by gas chromatography/mass spectrometry.