bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Agreement Among Routine Methods for Determination of Fluoride in Vegetation: Interlaboratory Collaborative Study
Authors: Jacobson Jay S , Troiano John J , Cosentini Christina C , Evans John
Published: February 2020

An interlaboratory collaborative study was conducted to evaluate the performance of methods and laboratories for the measurement of fluoride in vegetation. Samples of 8 plant species containing about 5-200 ppm fluoride were distributed to 40 participants who were instructed to use their routine methods of analysis. Methods which had sufficient participants to allow the inclusion of results in statistical analyses were classified into 3 categories: (1) Willard-Winter method (similar to the AOAC official final action method); (2) semiautomated and potentiometric methods (similar to the 2 AOAC official first action methods); and (3) potentiometric analysis with prior ashing, fusion, and/or distillation (not an approved method). There was a significant interaction of methods with samples caused by 3 of the 8 samples. In the other 5 samples, the Willard-Winter and semiautomated methods gave higher mean values for fluoride content than did the 2 potentiometric methods. Despite considerable improvement in speed and simplicity of fluoride analyses during the last decade, agreement between laboratories has not improved because of the variety of methods and techniques in use, the inherent differences between methods, and, apparently, poor laboratory quality control.
Bacillus stearothermophilus Disc Assay for Detection of Inhibitors in Milk: Collaborative Study
Authors: Messer James W , Leslie James E , Houghtby Gary A , Peeler James T , Barnett Jerald E ,   Collaborators:, Appelt A , Boone E , Bryant H , Burroughs L , Coleman K , Cupery M , Cyr R , Dombrowski P , Donahue P , Farmer S , Ginn R , Grant H , Hawkins J , Heady J , Herbst D , Kelley W , Misup M , Morris L , Mullen R , Ondrus N , Payton C , Seiz D , Share R , Stern M , Williams R
Published: February 2020

A 2-part (A and B) collaborative study was conducted on a Bacillus stearothermophilus paper disc (12.7 mm) method to detect residual inhibitors in milk. The 18 participating collaborators assayed raw milk samples spiked with a beta-lactam (penicillin G). Of the 18 collaborators, 14 participated in part A and 16 in part B. Part A demonstrated that either Antibiotic Medium No. 4 or PM Indicator Agar is suitable for use in the assay. The lowest concentration detectable, not significantly different from 100% at the α = 0.05 level, was 0.008 unit/mL with either medium. Part B demonstrated that the sensitivity of the method is equal to that of the current AOAC method (16.131- 16.136). The concentration of beta-lactam detected by 50% of the analysts was 0.003-0.005 unit/mL in this study, compared with 0.005 unit/mL reported in an earlier collaborative study on the current AOAC method. No false positive results were reported in part A or part B. All samples found positive by the confirmatory test in part B were correctly identified as a beta-lactam with commercial Penase discs. The lowest concentration detectable by the method, not significantly different from 100% at the α = 0.05 level, was 0.008 unit/mL. The method was adopted official first action.
Enzymatic Determination of Cholesterol in Egg Yolk
Authors: Shen Chih-Shang J , Chen Isabel S , Sheppard Alan J
Published: February 2020

The quantitative determination of cholesterol in egg yolk by using an enzymatic test kit is described. Cholesterol in the egg yolk is extracted with other lipid components by methylene chloride-methanol (2 + 1) and is enzymatically determined after saponification of the lipid extract. The method is relatively rapid, simple, and accurate and gives results which agree with those obtained by using a gas-liquid chromatographic (GLC) method. The mean cholesterol content of egg yolk determined by the enzymatic and GLC methods was 1237 and 1240 mg/100 g, respectively.
Analysis of Fat-Soluble Vitamins. XXVI. High Performance Liquid Chromatographic Determination of Vitamin D in Fortified Milk and Milkpowder
Authors: Borsje Ben , De Vries Ellen J , Zeeman Jakob , Mulder Frits J
Published: February 2020

Vitamin D is determined by high performance liquid chromatography (HPLC) in samples containing other fat-soluble vitamins. The vitamin D in the unsaponifiable residue is extracted and separated from interferences by straight phase chromatography, and the fraction corresponding to vitamin D3 is collected and quantitated using the AOAC official final action HPLC method for vitamin D3. Analysis of a synthetic mixture gave reasonable recoveries. The method measures potential vitamin D3 content in milkpowder samples containing 2IU vitamin D/g in the presence of all known vitamin D3 isomers, vitamin A, and vitamin E.
A Distributed Processing Laboratory Data System
Authors: Birkel Thomas J , Dusold Laurence R
Published: February 2020

Distributed data processing has been accomplished by a computer system in which laboratory instrument data are collected on a PEAK-11 system for preliminary processing and generation of initial reports. When further processing is required, or when archival storage of raw or processed data is desired, data are transferred over telephone lines to an IBM 3033; an IBM 7406 Device Coupler is used to handle protocol conversion and ″handshaking.″ User-written programs in APL.SV on the IBM machine and in Assembly Language on the PEAK-11 system effect the transfer of bidirectional data. The distributed processing approach allows efficient use of expensive peripherals while maintaining short response times.
Investigations on Nonsulfonamide Bratton-Marshall-Positive Compounds in Porcine Liver
Authors: Parks Owen W , Kimoto Walter I
Published: February 2020

An unknown Bratton-Marshall-positive compound was observed when liver extracts were screened by a procedure for the simultaneous determination of sulfamethazine and sulfathiazole in swine livers. The unknown has been conclusively identified as o-aminobenzoic acid (anthranilic acid), a tryptophan metabolite, by gas-liquid chromatography-mass spectrometry of swine liver extracts obtained by a modified Tishler procedure for sulfonamide residues in animal tissues.
High Pressure Liquid Chromatographic Determination of Sulfamethazine in Pork Tissue
Authors: Cox Byron L , Krzeminski Leo F
Published: February 2020

A high pressure liquid chromatographic (HPLC) method has been developed for determination of sulfamethazine residues in pork liver, kidney, muscle, and fat. The sample was extracted with acetone- chloroform, concentrated in the presence of dilute HC1, and partitioned between dilute HC1 and hexane. The acid solution was washed with methylene chloride and then buffered with trisodium citrate and sodium hydroxide to pH 5.8-5.9. Sulfamethazine was extracted from the aqueous mixture with methylene chloride, concentrated, dissolved in buffer, and eluted from XAD-2 resin with methanol. Sulfamethazine was reliably quantitated at 0.1 ppm by HPLC on a Zorbax ODS column with detection at 254 nm with no interference from tissues or reagents. The average recovery from the edible tissues, i.e., liver, muscle, kidney, and fat, fortified at 0.1-0.4 ppm was 85.6 ± 3.7%.
Mineral Oil Vacuum Distillation Method for Nitrosamines in Fried Bacon, with Thermal Energy Analyzer: Collaborative Study
Authors: Greenfield Earl L , Smith Wertice J , Malanoski Anthony J ,   Collaborators:, Benson M , Fiddler W , Grabber M , Herring H , Hill K , Legette L , Meyer K A , Robach M , Wolfe M
Published: February 2020

Nine laboratories participated in a collaborative study of a method for determining 6 nitrosamines, dimethylnitrosamine, diethylnitrosamine, dibutylnitrosamine, nitrosopiperidine, nitrosopyrrolidine, and nitrosomorpholine, in the 5-17 ppb range. The coefficients of variation for repeatability were 10.8, 8.5,10.4, 8.5, 8.7, and 7.8% with corresponding coefficients of variation for reproducibility of 16.4, 12.0,13.6,10.8,11.2, and 10.3% and recoveries of 89.6, 91.6, 84.7, 90.0, 89.6, and 88.1%, respectively. The method was adopted official first action.
High Performance Liquid Chromatographic Determination of Minor Saccharides in Corn Sugar: Collaborative Study
Authors: Engel C Earl , Olinger Philip M , Bernetti Raffaele ,   Collaborators:, Brobst K M , Holme R A , Lodge R E
Published: February 2020

The official first action AOAC method for quantitative determination of saccharides in corn syrup by liquid chromatography was reinvestigated to expand its scope to products containing dextrose in excess of 98%. Because of the low levels of saccharides other than dextrose (DP1), separations are carried out only of the DP1, the disaccharides (DP2), and the tri- and higher saccharides (DP3+) on an Aminex Q15-S, calcium form, cation exchange column. Concentrations of solids in water solvent injected into the liquid chromatograph are higher than those in the AOAC method to increase precision of analysis of the minor saccharides. All carbohydrate components in solution are eluted from the column; therefore, loss of refractive index detector linearity with respect to dextrose is compensated by use of an external maltose (DP2) standard to correct for DP2 and DP3+ response and dextrose is calculated by difference from 100. With mean values of 0.520% DP2 and 0.244% DP3+, the reproducibility and repeatability coefficients of variation are 14.6 and 6.7% for DP2, and 19.3 and 11.9% for DP3+, respectively. Dextrose levels of 99.23% are reproducible within 0.161. The coefficients of variation of the DP2 component are lower by this method than by the AOAC method at levels up to 2% DP2. The method has been adopted official first action.
AC Polarographic Determination of Cloxacillin
Authors: Nunez-Vergara Luis J , Silva Marisol M , Squella Juan A
Published: February 2020

Hydrolysis of cloxacillin at pH 4.0 yields an electro-active product which can be determined by polarography. Depending on the concentration of cloxacillin, one of 2 peaks was obtained: The potential ac peaks for a 4.36 mM cloxacillin solution were peak I, –0.23 V and peak II, –0.13 V. For analytical purposes, the first peak was used. A linear relationship was established for levels of cloxacillin between 2.2 × 10–5 and 2.2 × 10–3 M. Average recovery was 98.8% (SD 1.8), indicating satisfactory accuracy for the method. Individual capsule and composite assays as well as interference tests are described.
Quantitative Estimates of Beta-Lactam Residues in Raw Milk Around a Reference Standard: Collaborative Study
Authors: Ginn Roy E , Case Ronald A , Packard Vernal S , Tatini Sita R ,   Collaborators:, Bone E , Brizendine M , Curme A , Danilowier P R , Fuqua R , Grant H H , Heady J , Henrickson H , Kelley W N , Leslie J E , Schneider D E , Williams R R
Published: February 2020

A collaborative study was conducted to determine the reliability of a Bacillus stearothermophilus disc assay method for differentiating various concentrations of penicillin in raw milk. Participating laboratories tested 10 different samples (including one negative) in blind duplicate. Triplicate standards were alternated with triplicate unknowns around the periphery of each of 5 different plates. Zone diameters were measured and the difference in zone size of pairs of adjacent standard and unknown samples were analyzed by a paired t-test. Penicillin concentrations 0.003 IU/mL different from the reference concentrations were consistently distinguishable at a 95% confidence level. Such discriminatory power was determined to be possible with as few as 3 plates (9 replicates) per unknown. The method has been adopted official first action.
Capillary Gas-Liquid Chromatographic Determination of Vomitoxin in Cereal Grains
Authors: Huguette Cohen , Lapointe Michel
Published: February 2020

A gas-liquid chromatographic (GLC) method, using an electron capture detector, is described for determining vomitoxin in cereal grains at levels as low as 0.05 ppm. Samples are extracted with chloroform-ethanol and initially purified by using a Sep-Pak silica cartridge, followed by column chromatography using Sephadex LH-20. Additional purification is achieved by using a disposable cyano cartridge. Heptafluorobutyrylimidazole (HFBI) is added to form esters of the analytes. The HFB esters of vomitoxin are separated on a 30 m × 0.25 mm fused silica column coated with SE-54 and measured with a 63Ni electron capture detector. Samples were confirmed by gas-liquid chromatography/mass spectrometry using electron impact ionization and single ion monitoring at the molecular ion mass of 884.05 and at 10 000 resolving power. The method has been applied to wheat, oats, barley, and corn. The limit of detection is 0.05 ppm vomitoxin. Average recoveries were 89.8% with a coefficient of variation of 4.0%.
Nutritional Adequacy of Commercial Baby Foods
Authors: Yeung D L
Published: February 2020

The nutritional adequacy of commercial baby foods is assessed from data derived from a longitudinal nutrition survey of 400 infants in Canada. On the average, the nutrient intakes from infant food meet or exceed the recommended daily allowances for most nutrients. Most infants would not be able to meet the minimum daily requirements for iron, B vitamins, or calcium if infant cereals were not fortified.
Colorimetric Method for Field-Screening Above-Tolerance Parathion Residues on and in Citrus Fruits
Authors: Ott Daniel E , Gunther Francis A
Published: February 2020

A colorimetric technique has been developed which is suitable for use as a field-screening method for detecting above-tolerance levels of parathion on and in citrus fruits. By using this method, a grower should be able to postpone harvesting a crop until parathion residues are below tolerance level, so that the crop is safe to market. The method depends on the reaction of parathion with 4-(p-nitrobenzyl)- pyridine. Parathion is extracted by mixing chopped citrus rind with acetone in a hand-operated homogenizer. The extract is partially cleaned by a partitioning step before final cleanup with a Sep-Pak Florisil cartridge. The colored reaction solution is read at 560 nm by using a portable, rechargeable spectrophotometer. A single test can be completed in about 75 min; the average time per test when several are conducted sequentially is considerably shorter. The analytical system responds readily to <5 ppm parathion on or in 1 g navel orange rind, which corresponds to <1 ppm in the whole fruit. The present U.S. tolerance for parathion on or in citrus is 1 ppm on a whole fruit basis. Preliminary work indicates that the method should also be suitable for apples.
Automated Extraction Technique for Determination of Experimental Insecticide Nifluridide and Its Cyclized Product in Water by High Pressure Liquid Chromatography
Authors: West Sheldon D , Dorulla Georgia K , Poole George M
Published: February 2020

A method is described for the simultaneous determination of the experimental insecticide nifluridide (N-(2-amino-3-nitro-5-(trifluoromethyl)phenyl)- 2,2,3,3-tetrafluoropropanamide) and its cyclized product, EL-919 (7-nitro-2-(l,l,2,2-tetrafluoroethyl)- 5-(trifluoromethyl)benzimidazole), in water. Both compounds are extracted by passage of up to 500 mL water through two Sep-Pak C18 cartridges joined in series. The extraction is automated by using vacuum. The compounds are eluted from the cartridges with acetonitrile. Both compounds are then separated and measured by high pressure liquid chromatography with UV detection at 235 nm. Recoveries were 91.2-97.1% nifluridide and 82.7-98.0% EL-919 for deionized water samples fortified with 0.001-0.1 ppm nifluridide and 0.005-0.1 ppm EL-919. Analysis of water samples (pH 8) from bluegill and rainbow trout toxicity studies with nifluridide resulted in a half-life determination of 10 h at 13°C and 2.5 h at 20°C with nearly quantitative conversion to EL-919 within 96 h.
Fish Species Identification by Agarose Gel Isoelectric Focusing: Collaborative Study
Authors: Lundstrom Ronald C ,   Collaborators:, Annand M C , Barmore C R , Braddon S A , Caffrey B , Krzynowek J , Laird W , LaTerza A F , Lin T , Little B W , Mackie I M , Moodie I M , Morrison R , Odense P H , Leary G P O’ , Stiles S , Tuhkunen B E , Wiggin K
Published: February 2020

A method for fish species identification by agarose gel isoelectric focusing was collaboratively studied to determine if unknown samples could be identified by comparison of the unknown protein pattern with a photograph of protein patterns from authentic species. Fourteen collaborators were sent 19 or 20 unknown samples along with supplies and instructions for making pH 2.5-9.0 agarose isoelectric focusing gels. The unknown sarcoplasmic protein patterns were identified by comparison with a supplied 8 X 10 in. photograph of protein patterns from 18 authentic species. The 14 collaborators identified a total of 276 unknown samples with 84% accuracy. Eight of 14 collaborators averaged 90% or more correct. Two collaborators averaged 80-85% correct, while the remaining 4 collaborators averaged 50-69% correct. No one species was consistently misidentified; however, the method is not recommended for adoption in its present form.
X-Ray Powder Diffraction Data for Nine Anthelmintics
Authors: Owen John T R , Hashim Badruddin M , Underwood Frank A
Published: February 2020

X-ray powder diffraction data for identifying 9 anthelmintics have been obtained by dif fractometer and Debye-Scherrer camera techniques. The data are tabulated in terms of the lattice spacings and the relative intensities of the lines. Patterns using 3 different X-ray wavelengths with the camera method are compared with each other and with the dif fractometer patterns.
Automated Determination of Crude Protein, Phosphorus, Calcium, Iron, and Magnesium in Feeds by Using Stopped-Flow Analyzer
Authors: Koupparis Michael A , Diamandis Eleftherios P , Malmstadt Howard V
Published: February 2020

Methods are described for determination of crude protein, phosphorus, calcium, iron, and magnesium in feeds, using an automated microprocessor-based stopped-flow analyzer. Crude protein is determined by a reaction-rate procedure based on the ammonia- sodium phenate-hypochloride Berthelot reaction. Phosphorus determination is based on a phosphomolybdenum blue reaction-rate method. o-Cresolphthalein complexone, ferrozine, and calmagite are used as colorimetric reagents for calcium, iron, and magnesium, respectively. The methods are precise with relative standard deviations less than 1%, rapid with analysis rates of 110-266 samples per hour, sensitive, and require less than 1 mL sample and reagent volumes. Results for feed samples are comparable with those obtained by official AOAC methods.
Reverse Phase Liquid Chromatographic Determination of Sulfathiazole Residues in Honey
Authors: Barry Carla P , Maceachern Graham M
Published: February 2020

Sulfathiazole residues were extracted from honey by homogenizing samples in acetone, filtering, and then evaporating the acetone under nitrogen at 40°C. The remaining extract was transferred to a separatory funnel with IN HC1 and ethyl ether. An aliquot of the retained acid layer was screened by using the Bratton-Marshall reaction. If the test was positive, the remaining portion was analyzed directly through a μBondapak phenyl column monitored by a UV detector at 254 nm. The mobile phase was potassium phosphate monobasic in 10% acetonitrile adjusted to pH 3.0. Time for elution was 13 min. Average recoveries were 78% at the 0.1 ppm spiking level and 68% at the 1.0 ppm level. The minimum detectable amount was 0.06 ppm based on a spiked sample extract.
Assessment of Methods to Determine PCB Levels in Blood Serum: Interlaboratory Study
Authors: Burse Virlyn W , Needham Larry L , Korver Margaret P , Lapeza Chester R , Liddle John A , Bayse David D
Published: February 2020

Twenty-five laboratories participated in a study to determine the levels of polychlorinated biphenyls (PCBs) in 3 bovine serum pools, referred to as trial environmental pools (TEPs). TEPs 2 and 3 contained, respectively, low (9.97 ppb) and high (49.64 ppb) levels of PCBs (as in vivo-bound Aroclor 1254) and the same level of 9 commonly occurring chlorinated hydrocarbons. TEP 1 contained only naturally occurring levels of these analytes. Laboratories analyzed each sample in duplicate by the method used in their laboratory for measuring PCBs in blood serum. The coefficients of variation (CV) for the 12 laboratories reporting quantitative data and the required number of analyses for TEP 2 and TEP 3 were 37.0 and 30.7%, respectively. The mean recoveries for these 12 laboratories were 239.3 and 165.4% for TEP 2 and TEP 3, respectively. Three laboratories reported data with mean values for TEP 2 and TEP 3 within ± 3 standard deviations of the CDC characterized mean. Their coefficients of variation were 12.4 and 18.8% for TEP 2 and TEP 3, respectively. The mean recoveries for these 3 laboratories were 150.7 and 98.4% for TEP 2 and TEP 3, respectively. Our most significant observations were the laboratories’ failure to separate PCBs from DDTs and the excessive background of the reagent blanks. The widely discrepant results indicate a definite need to standardize methodology for this analysis.
Rapid Thin Layer Chromatographic Determination of Patulin, Citrinin, and Af latoxin in Apples and Pears, and Their Juices and Jams
Authors: Gimeno Alberto , Martins Maria Ligia
Published: February 2020

A method is described to determine the mycotoxins patulin, citrinin, and aflatoxins in apples and pears and their juices and jams. The mycotoxins are extracted with a mixture of acetonitrile and 4% aqueous KG (9 +1). The extract is cleaned up with water and then acidified, and the toxins are recovered with chloroform and separated by thin layer chromatography. Toxin identity is confirmed with various developing solvents, spray reagents, and chemical reactions, and then quantitated by the limit of detection method. The minimum detectable concentrations of the mycotoxins are patulin, 120-130 μg/kg; citrinin, 30-40 μg/kg; aflatoxin B1 or G1 , 2-2.8 μg/kg; af latoxin B2 or G2,2 μg/kg.
Survey of Vomitoxin Contamination of 1980 Ontario White Winter Wheat Crop: Results of Survey and Feeding Trials1
Authors: Trenholm H Locksley , Cochrane William P , Cohen Huguette , Elliot James I , Farnworth Edward R , Friend Douglas W , Hamilton Robert M G , Standish James F , Thompson Brian K
Published: February 2020

During the harvesting of the 1980 Ontario white winter wheat crop, producers noticed pink discoloration on kernels; this was attributed to Fusarium mold. Grain elevator and boatload samples were analyzed for mycotoxin contamination. Vomitoxin levels up to 8 ppm were detected in samples from southwestern Ontario. Other suspected mycotoxins were either nondetectable or present in trace amounts. Fusarium-contaminated wheat and clean wheat were added to swine and poultry diets for feeding trials. Feed refusal and decreased weight gains were observed in pigs fed diets containing 0.3 and 0.7 ppm vomitoxin, but there was no vomiting or other ill effects. Adult roosters and laying hens fed diets containing vomitoxin levels similar to those of the pig diets did not show any overt toxicological effects. Chemical analysis of suspected field cases of vomitoxin-contaminated feed did not reveal high vomitoxin levels.
International Mycotoxin Check Sample Survey Program. Part III. Report on Performance of Participating Laboratories for Determining Ochratoxin A in Animal Feed
Authors: Friesen Marlin D , Garren Liliane
Published: February 2020

A sample of animal feed made from barley, naturally contaminated at about 1000 μg ochratoxin A/kg, was analyzed by 44 laboratories in 24 countries. The AOAC method for determining ochratoxin A in barley was used by 27 (61%) of the participating laboratories. Results from laboratories using this method were grouped around 2 maxima: one below 100 μg/kg and a second near 940 μg/kg, the median concentration for results reported by all 44 participating laboratories. Results from laboratories using methods other than the AOAC method were more widely distributed with no apparent maximum near 1000 μg/kg.
Spectrofluorometric Determination of Pindolol and Its Dosage Form
Authors: Mohamed Mohamed E , Tawakkol Mostafa S , Aboul-Enein Hassan Y
Published: February 2020

A new direct, simple, and sensitive spectrofluorometric method is described for the assay of pindolol and its tablets at room temperature, using ethanol (96% v/v) as solvent. The drug exhibits intrinsic fluorescence. Working wavelengths are 263 nm for excitation and 305 nm for emission. The calibration curve is linear in the range 1.0 × 10-7 to 1.5 × 10-6M pindolol.
High Pressure Liquid Chromatographic Determination of Toxins Associated with Paralytic Shellfish Poisoning
Authors: Sullivan John J , Iwaoka Wayne T
Published: February 2020

A high pressure liquid chromatographic procedure is described for assay of toxins associated with paralytic shellfish poisoning (PSP). The method is applicable to saxitoxin, neosaxitoxin, gonyautoxins I through IV, and their sulfocarbamoyl derivatives. Toxins are separated on a bonded phase cyano column and detected by fluorescence following alkaline oxidation (NHNH4+ and periodic acid). The utility of the HPLC procedure for research and monitoring is discussed.
High Performance Liquid Chromatographic Analysis of Diflubenzuron and Its Formulations: Collaborative Study
Authors: Rossum Bram Van , Martijn Albertus , Reijke Albert A De , Zeeman Jakob ,   Collaborators:, Åkerblom M , Bosshardt H P , Bushway R J , Damme J C van , Darskus R , Kolleman J , Pavel K , Pilar-Hitos M , Pouwelse A , Sãnchez-Rasero F , Stewart T , Suter R , Tengler H , Winsauer K , Wisson M
Published: February 2020

Diflubenzuron 90% pre-concentrate and its 25% water-dispersible powder were analyzed by a high performance liquid chromatographic method. Six samples were extracted with 1,4-dioxane, linuron was added as internal standard, and diflubenzuron was separated on a 25 cm × 4.6 mm column packed with Zorbax BP-C8 with acetonitrile-water-l,4-dioxane (450 + 450 + 100) at 1.3 mL/min and monitored at 254 nm. Results were obtained from 17 laboratories. Within-laboratory repeatability was 0.6% for both the pre-concentrate and the water-dispersible powder samples and the reproducibility was 1.2%. The method has been adopted as a full CIPAC method and was adopted official first action by AOAC.
Effect of Citric Acid on Inhibition of Chlortetracycline Activity by Magnesium Ions
Authors: Burgess Tamara , Chiang Tom
Published: February 2020

The antimicrobial activity of chlortetracycline (CTC) can be inhibited by magnesium ions; thus the result of CTC turbidimetric assay may be lower than guarantee if large amounts of magnesium ions are present in the feed extract. Under controlled conditions, citric acid can be used to chelate the excess magnesium ions without affecting cell growth or CTC activity, thereby eliminating the magnesium interference.
Rate Nephelometric Measurement of Wheat Germ in Pasta Products
Authors: Bracciali Alberto , Cantagalli Piero , Antoni Guido , Tarli Paolo , Neri Paolo
Published: February 2020

An immunoassay for the rate nephelometric determination of wheat germ added to pasta products has been developed using a specific wheat germ antiserum. The method can be used to analyze germ from either soft or hard wheat. Specially prepared pasta products and commercial preparations were analyzed with the immunonephelometric method, in comparison with the radial immunodiffusion technique; good correlation was found between the results of the 2 assay.
Determination of Organic Phosphate Triesters in Human Adipose Tissue
Authors: LeBel Guy L , Williams David T
Published: February 2020

A method of analysis has been developed for the determination of organic phosphate triesters in human adipose fat at low ng/g levels. After fat extraction from the tissue with benzene (or acetone-hexane, 15 + 85, v/v), phosphates were fractionated from fat by gel permeation chromatography with methylene chloride-cyclohexane (5 + 95, v/v) as solvent. After Florisil column cleanup, the GPC extract was analyzed by capillary column gas chromatography using a nitrogen-phosphorus selective detector. Recoveries at the 2.5,10, and 25 ng/g levels were greater than 75% except for tri(2,4-xylenyl) phosphate (ca (57c). Of 16 human adipose tissue samples analyzed, 5 contained tris(l,3-dichloropropyl) phosphate in the range of 0.5 to 110 ng/g, 4 contained tributoxyethyl phosphate in the range of 4.0 to 26.8 ng/g, and one contained tributyl phosphate at 9.0 ng/g.
Interlaboratory Study on Determination of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Fish
Authors: Ryan John J , Pilon Jean C , Conacher Henry B S , Firestone David
Published: February 2020

An interlaboratory round robin study was carried out to estimate the reliability of data on 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD) in fish. Using different methods, 13 laboratories (4 Canadian, 9 American) agreed to analyze 4 fish samples; 3 were Great Lakes salmonids containing bio-incurred levels of TCDD below 100 ppt and the fourth was an ocean fish fillet containing no measurable TCDD. Samples were sent as freeze-dried portions as it was shown that no change of TCDD occurred by this sample preparation. Results were normalized between laboratories by supplying each with an aliquot of the same 2,3,7,8-TCDD standard. Eight laboratories reported a set of results of which one set was rejected. Values from the 7 remaining laboratories for the 3 positive fish showed mean concentrations in pg/g (ppt) and (CV, %) of 61.2 (13.9), 30.4 (18.4), and 32.3 (25.4). Detection limits averaged 3.6 ppt and ranged between 1 and 10 ppt. No significant differences appeared in the concentration of 2,3,7,8-TCDD in fish samples from methods differing in the use of: (i) digestion or extraction techniques, (ii) high or low resolution mass spectrometry, and (iii) isomer specific or nonspecific separations. Overall recovery values using internal standards varied greatly (29-109%) even within the same laboratory and pointed to the need to use an internal standard to obtain precise results. Agreement among laboratories was good considering the level quantitated (ppt) and the diverse methodology.
Gas-Liquid Chromatographic Determination of Benzoic Acid and Sorbic Acid in Foods: NMKL1 Collaborative Study
Authors: Larsson Bonny K ,   Collaborators:, Askeland M , Bergstrøm-Nilsen M , Dahle H K , Halen B , Hasselrot I-L , Kiutamo T , Odklev K-Å , Pääbo K , Rajama J , Willumsen D
Published: February 2020

A gas-liquid chromatographic method for the simultaneous determination of benzoic acid and sorbic acid in foods was collaboratively studied by 8 laboratories. Benzoic and sorbic acids are isolated from food by successive extractions with ether, sodium hydroxide, and methylene chloride, converted to trimethylsilyl (TMS) esters, and determined by gasliquid chromatography. Phenylacetic acid and caproic acid are used as internal standards for benzoic acid and sorbic acid, respectively. Seven samples were collaboratively studied: almond paste, fish homogenate, and apple juice with benzoic and sorbic acid levels from 0.04 to 2 g/kg. Average recoveries {%) for benzoic and sorbic acids were as follows: almond paste, 99.6 and 101.2; fish homogenate, 99.2 and 97.4; and apple juice 98.2 and 106.6. The reproducibility coefficients of variation (%) for benzoic and sorbic acids at 0.5-2 g/kg levels were 3.5-6.1 and 5.2-9.0; and at the 0.04 g/kg level, 14.7 and 23.3, respectively. The method has been adopted official first action at 0.5-2 g/kg levels.
Simultaneous Determination of Folpet, Piperonyl Butoxide, and Pyrethrins in Aerosol Formulations by High Pressure Liquid Chromatography
Authors: Perez Rafael L
Published: February 2020

A high pressure liquid chromatographic (HPLC) method is described for the simultaneous determination of folpet, piperonyl butoxide, and pyrethrins in aerosol pesticide formulations. The aerosol propellants are removed from the can and the remaining components are determined by HPLC, using an U1-trasphere 5 μm ODS reverse phase column and a UV detector at 254 nm. Recoveries for the 3 components are greater than 98%.
Analysis of Pesticide Residues by Chemical Derivatization. VII. Chromatographic Properties of Pentafluorobenzyl Ether Derivatives of Thirty-two Phenols1
Authors: Lee Hing-Biu , Chau Alfred S Y
Published: February 2020

A gas-liquid chromatographic (GLC) procedure is described for the identification of 32 substituted phenols including all 19 chlorophenols and the 11 U.S. Environmental Protection Agency consent decree phenols. This method involves a simple and reproducible derivatization step which forms stable phenol PFB ethers for which the electron capture detector is highly sensitive. GLC retention time data of the derivatives on 6 packed and fused silica capillary columns (FSCC) are reported. The detection limits of all chloro-, alkyl- and mono-nitrophenols studied are between 0.5 and 5 pg injected for an FSCC. The high resolution of these capillary columns makes this method isomer-specific. The derivatization procedure also eliminates the sensitivity, tailing, and resolution problems commonly encountered in other gas chromatographic methods on underivatized phenols.
Gas-Liquid Chromatographic Determination of T-2 Toxin in Plasma
Authors: Swanson Steven P , Ramaswamy Venkatachalam , Beasley Val R , Buck William B , Burmeister Harold H
Published: February 2020

The gas-liquid chromatographic method for the determination of T-2 toxin in plasma is described. The toxin is extracted with benzene, washed with aqueous sodium hydroxide, and chromatographed on a small Florisil column; the heptafluorobutyryl derivative is prepared by reaction with heptafluorobutyrylimidazole. The T-2 HFB derivative is chromatographed onOV-1 at 230°C and measured with an electron capture detector. Iso-T-2, an isomer of T-2 toxin, is added to samples as an internal standard before extraction. Recoveries averaged 98.0 ± 5.5% at levels ranging from 50 to 1000 ng/m L. The limit of detection is 25 ng/mL.
Effect of Heat Treatment on Dietary Fiber: Interlaboratory Study
Authors: Varo Perth , Laine Raili , Koivistoinen Pekka ,   Participants:, Asp N-G , Menger A , Reimann S , Robertson J B , Schweizer T F , Selvendran R R , Siljestrom M , Southgate D A T , Theander O , Soest P J Van , Westerlund E
Published: February 2020

The effects of thermal treatments on the dietary fiber composition of cereal and potato samples were studied at 8 laboratories using different analytical methods. Thermal treatments included extrusion cooking for cereals, and boiling and frying for potatoes. No changes in the amounts of dietary fiber or starch were observed in the extruded samples. Heat-treated potato samples contained significantly more water-insoluble dietary fiber (cellulose) and less starch than did raw potato. However, this may be due, at least in part, to the sample preparation procedure rather than the heat treatment alone. The study indicates that gravimetric and sequential hydrolysis methods give similar results, but the variation in most cases is still wide. Further standardization of methods is evidently needed, especially if legislative measures for setting limits on the fiber content of foods are to be introduced. Standardization of starch analysis should also be of primary importance in future work on carbohydrate methodology. This can be concluded from the variation in results concerning this extremely important food constituent. It should be noted that the sample matrix in the present study was simpler than that of complex meals or diets.
Titrimetric Determination of Calcium in Mechanically Separated Poultry and Beef: Collaborative Study
Authors: Corrao Paul A , Malanoski Anthony J , Curry Kevin A , Glover Angeline ,   Collaborators:, Covington R , Deban N , Gallagher D , Mendez R Rivera , Scheib C A
Published: February 2020

A collaborative study was conducted on a titrimetric EDTA method for the determination of calcium in mechanically separated poultry and beef tissue. Six laboratories analyzed, as blind duplicates, 5 poultry samples and 5 beef samples. Calcium concentrations covered the levels from 0.04 to 0.82%. Pooled standard deviations were 0.0165 for repeatability, 0.0072 for bias, and 0.0225 for reproducibility. The method has been adopted official first action.
High Pressure Liquid Chromatographic Determination of Brodifacoum in Formulations: Collaborative Study
Authors: Bland Peter D ,   Collaborators:, Freedlander R , Gentry M , Hindle R , Hodgins E , Parker R , Plunkett R , Pracht L , Sergeant D , Wood G
Published: February 2020

A method is described for the determination of brodifacoum in technical and formulated material by high pressure liquid chromatography (HPLC). Samples of technical or formulation are dissolved in a solution of 1,3,5-triphenyl benzene in dichloromethane and methanol. The solution is injected into an HPLC system fitted with 25 cm Zorbax ODS column and an ultraviolet detector. The solution is eluted with a mixture of methanol, water, and acetic acid. Quantitative data are obtained by comparing peak areas of the compound and triphenyl benzene with those obtained by injecting a standard solution. Bait formulations are extracted into dichloromethane-formic acid, filtered, and concentrated by evaporation before chromatography. Nine collaborators made replicate determinations on 4 samples including technical material, a 0.1% powder, a 0.25% liquid, and a 0.005% pelleted bait formulation. They also carried out a recovery experiment on the bait product. Coefficient of variation (%) were 1.21 on the technical product, 13.49 on the powder, 2.40 on the liquid, and 11.06 on the bait. Insufficient data were generated to adequately quantitate the recovery factor. The method has been adopted official first action for the analysis of technical material, liquid, and bait formulations.
Retention Time Data for Organochlorine, Organophosphorus, and Organonitrogen Pesticides on SE-30 Capillary Column and Application of Capillary Gas Chromatography to Pesticide Residue Analysis
Authors: Ripley Brian D , Braun Heinz E
Published: February 2020

Relative retention time data for 194 pesticides and metabolites are reported for a 15 m SE-30 capillary gas chromatographic column under a single temperature programmed regime. The reproducibility of retention time and quantitation is discussed and the performance of electron capture and nitrogenphosphorus thermionic detectors is evaluated in relation to pesticide residue analysis.
Proof Determination of Liqueurs and Alcoholic Dairy Products: Collaborative Study
Authors: Strunk Duane H , Timmel Bertha M , Rapp Frances L , Aicken John C ,   Collaborators:, Andreoli R J , Cherolis J , Daggs W D , Mark F G , O’Bryan W C , Perrault A W , Rapp F L , Steinke R D , Timmel B M , Thurman W A
Published: February 2020

A method is described for determining the ethanol concentration of liqueur-type products containing dissolved solids. The sample is distilled in an allglass still equipped with spherical joints; the proof of the distillate, diluted to known volume, is measured by a Mettler/Paar density meter. Ten collaborators determined proof of 6 different synthetic liqueurs containing ethanol-water-sugar mixtures and 2 alcoholic dairy products. Proof of the samples varied from 33 to 92°. Standard deviations and coefficients of variation for this method varied from 0.069 to 0.278 and from 0.20° to 0.36°, respectively. The method has been adopted official first action.
High Performance Liquid Chromatographic Determination of Dielofop-Methyl
Authors: Stringham Rodger W , Bennett Brian R
Published: February 2020

Diclofop-methyl is diluted in acetonitrile-2% acetic acid (70 + 30) and chromatographed on a reverse phase C-18 column. The anaìyte is eluted by an acetonitrile- 2% acetic acid mobile phase and detected at 280 nm. The method was validated by testing precision, linearity, and recovery. Precision and linearity were excellent (% RSD = 0.55, r2 = 0.9997). A multiple standard addition to a pool of formulation samples showed the method to have excellent recovery (99%) and to be free of matrix interferences
Gas-liquid Chromatography and Nitrogens-Phosphorus Detection of N-Nitroso-di-n-Propylamine in Trifluralin Products
Authors: Maybury Ronald B , Grant Ralph G
Published: February 2020

A method is described for the determination of trace levels of N-nitroso-di-n-propylamine (NDPA) in trifluralin herbicide formulations. Following sample extraction, NDPA is separated on a silica gel column and determined by gas-liquid chromatography with a nitrogen-phosphorus detector (NPD). A comparison between the results obtained using this detection system and the thermal energy analyzer (TEA) for 0.5-5 ppm levels of NDPA in 17 samples showed no significant differences. Close agreement was also demonstrated with the results obtained by high resolution gas-liquid chromatography/mass spectrometry (GLC/MS). The minimum detectable amount of NDPA with the NPD was 5 pg, for the TEA system 50 pg, and for high resolution GLC/MS 100 pg. A number of other nitrosamines were detected by all systems in one sample but these were not fully characterized. The nitrogen-phosphorus detector is useful for monitoring traces of NDPA in trifluralin when preceded by cleanup on a silica gel column.
Liquid Chromatographic Determination of Glyphosate Technical and Its Formulation: Collaborative Study
Authors: Burns Arnold J ,   Collaborators:, Audino J B , Bennett O O , Gale G T , Glinski R , Owens M E , Parker J J , Peake A , Rowe N , Sorensen E V , Torma L , Valange B M
Published: February 2020

An HPLC method for the determination of glyphosate in formulation and technical samples has been subjected to a collaborative study with 12 laboratories participating. This method requires no sample pretreatment. Samples were dissolved in mobile phase, injected directly using a fixed-volume loop, and quantitated by an external standard technique. Compounds were separated on a strong anion exchange column with a water-methanol (96 + 4) mobile phase that was 0.0062M in KH2P04 and adjusted to pH 1.9 with 85% H3PO4, and detected with a variable wavelength UV detector at 195 nm. Calculations were made using peak areas. The collaborative study involved 3 pairs of matched samples with single determinations on each sample: Roundup herbicide, a technical intermediate, and technical glyphosate. The coefficients of variation for the 3 pairs were 1.70, 0.88, and 0.90%, respectively. The method has been adopted official first action.
Novel Method for Estimation of Chlorinated Pesticide Residues in Milk
Authors: Adachi Kazuhiko , Ohokuni Nobuyuki , Mitsuhashi Takao , Yoshida Masashi
Published: February 2020

A new, simple, and rapid procedure for determining chlorinated pesticide residues in milk is described. The entire acetonitrile extract from milk is passed through a 0.5 g activated charcoal chromatographic column. Chlorinated pesticides adsorbed on the charcoal are eluted with 100 mL acetone-hexane (1 + 1). The eluate is washed with water and 1% sodium carbonate solution, and chlorinated pesticides are extracted with hexane. The extract is concentrated and measured by electron capture gas chromatography. Recoveries from 50 mL milk samples fortified with 0.04-1.6 μg of different BHC isomers, 0.05-2 μg DDT and its metabolites, and 0.05-0.5 μg dieldrin ranged from 86.9 to 103.2%.
Gas Chromatographic Determination of Mixtures of Captan, Folpet, and Captafol
Authors: Gilvydis Dalia M , Walters Stephen M
Published: February 2020

A gas chromatographic procedure, using electron capture detection, has been studied and found to be applicable for determining 3 structurally similar fungicides, captan, folpet, and captafol, which are often found in combination in certain foods. Eight liquid stationary phases (AN-600, OV-25, OV-101, OV-210, OV-225, QF-1, SP-2401, and XE-60) were evaluated. A fluorosilicone stationary phase of moderate polarity, SP-2401, was best suited for column stability, response, resolution of captan and folpet, and freedom from on-column decomposition of the 3 fungicides.
Mixed Acid Solubilization Procedure for Determination of Total Mercury in Food Samples
Authors: Marts Ronald W , Blaha John J
Published: February 2020

A mixed acid solubilization procedure has been developed for the determination of total mercury in food samples. This procedure has eliminated the problem of mercury loss from samples that are high in lipid or carbohydrate content. The solubilization is rapid and quantitative and can be used for a wide range of food items.
Ion-Pair Liquid Chromatographic Determination of Uncombined Intermediates in Three Synthetic Food Colors
Authors: Lancaster Frank E , Lawrence James F
Published: February 2020

Uncombined intermediates are determined in samples of food colors by reverse phase liquid chromatography with a mobile phase containing tetra-n-butylammonium phosphate. The intermediates are separated from the primary dyes and are quantitated by using known standards. The intermediates naphthionic acid and R-salt (2-naphthol-3,6-disulfonic acid, sodium salt) were determined in spiked samples of Amaranth with recoveries of 98-102%. Similar results were obtained for sulfanilic acid and Schaeffés salt (2-naphthol-6-sulfonic acid, sodium salt) in Sunset Yellow FCF (FD&C Yellow No. 6) and for sulfanilic acid and PyT (l-(4-sulfophenyl)-3-carboxy- 5-hydroxypyrazolone) in Tartrazine (FD&C Yellow No. 5) with recoveries of 96-105%. Spiking levels, in all cases, were in the range 0.05-1.0% total intermediates. The method compares favorably with results obtained by either ion-exchange liquid chromatography or cellulose column chromatography for a number of commercial samples.
Rapid Colorimetric Assay of Trimethoprim and Sulfamethoxazole in Pharmaceuticals
Authors: Sanyal Asis K , Laha Dinabandhu
Published: February 2020

A method is described for the direct colorimetric determination of trimethoprim and sulfamethoxazole in pharmaceutical preparations, without prior separation. Estimation of trimethoprim is based on its ion-pair formation with bromophenol blue and subsequent measurement of absorbance of the ionpair at 418 nm. Estimation of sulfamethoxazole is possible without removal of trimethoprim by solvent extraction.
Rapid Liquid Chromatographic Determination of Aflatoxins in Heavily Contaminated Corn
Authors: Hutchins James E , Hagler Winston M
Published: February 2020

A procedure is described for rapid, quantitative determination of aflatoxins B1, B2, G1, and G2 in heavily contaminated corn (>500 μg B1/kg) from field, greenhouse, and growth chamber experiments employing artificial inoculation of corn with Aspergillus flavus. Whole kernel corn is ground to pass a 1 mm screen and mixed before extraction of a water-wetted (25 mL) 50 g subsample with 250 mL chloroform. The filtered extract is diluted 1:1 with hexane and applied to a hexane-wetted (10 mL) disposable silica cartridge. Interferences are removed with chloroform-hexane (1 + 3), and aflatoxins are quantitatively eluted with hexane-acetone (1 + 1). Aflatoxins B1 and G1 are converted to the more intensely fluorescent hemiacetals, B2a and G2a, by treatment with trifluoroacetic acid-water. Derivatized aflatoxins are separated by reverse phase liquid chromatography (LC) and quantitated fluorometrically. Compared with AOAC method I (CB) for corn, using samples containing approximately 50 and 10 000 μg B1/kg, agreement between methods was good at the lower level while the rapid method yielded a considerably larger mean at the higher level. A precision study of 30 replicate samples produced a coefficient of variation of 8.46% at a mean value of 1066 μg B1/kg. The cartridge method was developed for LC analysis of samples that contain >500 μg aflatoxin B1/kg corn, but it may be used to quantitate as little as 10 μg B1/kg with no modification.