bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Tilmicosin in Bovine Milk by Liquid Chromatography with Ultraviolet Detection
Authors: Ngoh Maureen A
Published: February 2020

A method is described for determining tilmicosin in bovine milk by liquid chromatography with ultraviolet (UV) detection. Samples are defatted by centrifugation. The lower skim layer is cleaned on a C18 solid-phase extraction cartridge. The extract is concentrated and analyzed with a reversed-phase phenyl column with UV detection at 280 nm. The method was validated with control milk fortified at 50,100, and 200 ng/mL. Average recoveries (and intralaboratory coefficients of variation) were 97% (9%), 98% (5%), and 101% (3%), respectively. The limit of quantitation is approximately 20 ng/mL, and the limit of detection is approximately 13 ng/mL. The method was tested on milk from a cow dosed with tilmicosin.
Determination of Sugars, Starches, and Total Dietary Fiber in Selected High-Consumption Foods
Authors: Li Betty W
Published: February 2020

A general scheme has been developed to determine sugars, starches, and total dietary fiber (TDF) in half-gram freeze-dried subsamples of various foods (or wet samples containing about 0.5 g dry matter). Duplicate subsamples are extracted for free sugars with 80% methanol, dried, derivatized to their trimethylsilylated oximes or ethers, and quantitated by gas–liquid chromatography (GLC). Residues after 80% methanol extraction are incubated with a solution containing amyloglucosidase in acetate buffer. Hydrolyzates are centrifuged, and duplicate aliquots are removed for glucose determination by GLC. Starch content is calculated as glucose (g/100 g) × 0.9. Remaining hydrolyzates are diluted with 4 volumes of 95% ethanol, left at room temperature for 1 h, and then filtered through glass crucibles matted with Celite filter aid. The weight of dry residues are corrected for residual crude protein and ash, and the resulting values are taken to be the TDF content of a sample. A variety of high- consumption foods selected by the Nutrient Data Laboratory of the Agricultural Research Service were analyzed for carbohydrate fractions by this method. Values for total sugar and dietary fiber were compared with those obtained by a commercial laboratory using different methods.
Automated Spectrophotometric Method Using 2,2’-Dithiodipyridine Acid for Determination of Cholinesterase in Whole Blood
Authors: Cerón Jose J , Palacio María J Fernandez Del , Bernal Luis J , Gutierrez Cándido
Published: February 2020

An automated method using 2,2’-dithiodipyridine (2-PDS) as chromophore for determination of wholeblood cholinesterase activity was developed. Assay procedures, optimal concentrations of chromophore and substrate, detection limit, precision, backgrounds, and sensitivity of the method were compared with those of an earlier automated method based on the Eilman method and using 5,5’-dithiobis(2-nitrobenzoic acid) (DTNB) as chromophore. The new method has the advantages of automation (resulting in increase throughput rate and decrease in amount of reagents used) and good precision and sensitivity. Sample dilutions also are reduced in the new method because hemoglobin interference is less.
Effect of USP Apparatus 1 and 2 at Different Rotational Speeds on Dissolution of Niacin Formulations
Authors: Kirchhoefer Ross D , Hamilton Jimmy F
Published: February 2020

Forty-four niacin formulations were examined by the United States Pharmacopeia dissolution test, consisting of 0.1 N HCl with apparatus 1 and 2. Each formulation was tested with apparatus 1 (basket) at 100 rpm and apparatus 2 (paddle) at 50 and 100 rpm. Dissolution results varied widely among manufacturers.
Identification and Determination of the Isomeric Bromo- and/or Chloro-Substituted l,3-Dihalo-5,5- Dimethylhydantoins Used in Disinfectants and Molluscicides
Authors: Beihoffer Jon , Bour Ed , Lowry Joe H , Reschl John J , Seidel Jivbmy L , Gibson Charles P
Published: February 2020

Proton nuclear magnetic resonance spectrometry (1H NMR) was used to identify and quantitate the 4 isomeric bromo- and/or chloro-substituted 1,3-dihalo-5,5-dimethylhydantoins in technical-grade materials used to prepare commercial disinfectants and molluscicides. We found that the technical grades of bromo/chloro-substituted 1,3-dihalo-5,5-dimethylhydantoins are mixtures of the 4 possible isomers, that interconversion among isomers occurs in solution and can be detected by 1H NMR, and that isomer interconversion occurs over times greater than those of the NMR timescale.
Determination of Lincomycin Residue in Salmon Tissues by Ion-Pair Reversed-Phase Liquid Chromatography with Electrochemical Detection
Authors: Luo Wenhong , Hansen Eugene B , Ang Catharina Y W , Thompson Harold C
Published: February 2020

A method is described for detecting and quantitating lincomycin residue in salmon muscle and skin tissues by ion-pair reversed-phase liquid chromatography (LC) with electrochemical detection at +0.9 V. Lincomycin was extracted from tissues by homogenizing with 0.01 M KH2PO4 buffer (pH 4.5) and centrifuging the mixture. Water-soluble proteins were precipitated by adding sodium tungstate and sulfuric acid and removed by cent r if u gat ion. The buffer extract was then passed through a C18 solid-phase extraction cartridge. Lincomycin was eluted with 50% acetonitrile in water, and the eluate containing lincomycin was extracted with ethyl acetate. After the solvent had evaporated, the residue was redissolved in mobile phase and analyzed by LC. The method had a limit of detection of 7 ng/g lincomycin for salmon muscle and 12 ng/g for salmon skin. The limit of quantitation was 17 ng/g for salmon muscle and 24 ng/g for salmon skin. Average recoveries of lincomycin spiked at 50,100, and 200 ng/g were ≥85% for salmon muscle and ≥80% for salmon skin.
Organochlorine and Organophosphonis Pesticide Residues in Food from Egyptian Local Markets
Authors: Dogheim Salwa M , Gad Alla Sohair A , El-Syes Sami M A , Almaz Monir M , Salama Emel Y
Published: February 2020

A market basket survey was conducted to monitor organochlorine and organophosphorus pesticide residues in potatoes, citrus fruits, and fish collected from local Egyptian markets. Maximum Residue Limits (MRLs) of the Codex Committee on Pesticide Residues for γ-hexachlorocyclohexane (HCH) in potatoes were exceeded in 8 samples and for DDT in 2 samples. The aging of HCH and DDT indicated a recent use of both pesticides during the potato storage period between cultivation seasons. However, such use is illegal because HCH mixture isomers (gammaxane) and DDT have been officially prohibited from agricultural use in Egypt since 1980. The highest residue levels of fenitrothion (3.8 ppm) in potatoes may be due to its repeated use before and after harvest. No organochlorine pesticide residues were found in citrus fruits. None of the detected organophosphorus pesticides exceeded their MRLs. HCH and DDT residue limits were exceeded in 5 and 7 fish samples, respectively, collected from 12 markets throughout the country. The heptachlor MRL was violated in only one fish sample (3.9 ppm).
Levels of Cd, Hg, As, Cu, Mil, and Zn in Japanese Restaurant and Box Lunches
Authors: Tsuda Taizo , Kojima Mihoko , Harada Hiroyuki , Nakajima Atsuko , Aoki Shigeru
Published: February 2020

Intakes of selected elements from restaurant and box lunches in Shiga Prefecture (Japan) were investigated in 1993 and 1994, respectively. Average intakes of these elements from restaurant and box lunches were, respectively, 14 and 12 μg for Cd, 4.6 and 4.5 μg for Hg, 85 and 91 μg, for As, 461 and 561 μg for Cu, 1268 and 1235 μg for Mn, and 3612 and 2688 ug for Zn. There were no great differences between the intakes from the restaurant lunches in 1993 and the box lunches in 1994. The proportion of elements from the lunches constituted 25-38% of the daily intake for Cd, As, Mn, and Zn and 51-65% of the daily intake for Hg.
Homogeneity of Fruits and Vegetables Comminuted in a Vertical Cutter Mixer
Authors: Young Susan J V , Parfitt Charles H , Newell Richard F , Spittler Terry D
Published: February 2020

The homogeneity of comminuted composites of 20 lb samples of apples, cabbage, and green beans containing field-incurred residues of p,p′-methoxychlor was studied to determine whether a 5 min comminution in a 40 qt vertical cutter mixer produces a homogeneous composite and whether the size of test portions used accurately represents the composite. Duplicate test portions of 100,50,25, 10,5, and 2 g taken from each of 6 separate sections of the mixer were analyzed by standard pesticide residue methodology for p,p′-methoxychlor. Results of this study confirmed that comminution of fresh produce in a 40 qt vertical cutter mixer, according to instructions described in the U.S. Food and Drug Administration's Pesticide Analytical Manual, Volume 1, section 203B, produces a homogeneous composite. No significant differences were found in the data for the 3 crops taken from the 6 sections of the mixer. Test portion weights of 100, 50, and 25 g produced equivalent results for all 3 crops. Statistically significant differences were observed for cabbage at 2,5, and 10 g and for green beans at 2 g.
Improvement of Calibration Curve for Determining Peroxide Values of Food Lipids by the Modified Ferrous Oxidation-Xylenol Orange Method
Authors: Burat Kutlay M , Bozkurt Onur
Published: February 2020

The linearity range of the standard Fe+3 calibration curve for measuring lipid hydroperoxides in food samples by the modified ferrous oxidation-xylenol orange (mFOX) method was extended from 5-20 μg to 2-40 μg by establishing the best concentration of xylenol orange in the same assay system. Butter, fish oil, and some vegetable oils were analyzed by the International Dairy Federation method and the improved mFOX method, and results were compared.
Determination of Sulfur in Fertilizers by Inductively Coupled Plasma-Atomic Emission Spectrometry: Spectral and Interelement Effects at Various Wavelengths
Authors: Matilainen Rose , Tummavuori Jouni
Published: February 2020

Three analytical wavelengths (180.731,182.037, and 182.625 nm) were tested for determination of sulfur in 2 fertilizers by inductively coupled plasmaatomic emission spectrometry (ICP-AES). Variable S results at 182.037 nm were caused by a downward sloping background shift (Fe line at 181.851 nm) during measurement of the sample solutions. At 182.625 nm an emission peak doublet, 182.619/182.635 nm, was observed from which the instrument selected the measurement peak. A shift from calibrated peak 182.619 nm to noncalibrated peak 182.635 nm occurred when the S/B ratios were ≤22-31 in the fertilizer samples examined. For the 3 wavelengths of S investigated, the pattern of spectral and interelement interference changed at the same wavelength according to the composition of the fertilizer. K, P, and Mg typically caused interelement effects and Ca and B caused spectral effects during S determination. In the interference studies, 180.731 nm proved the best wavelength for the ICP-AES determination of S in fertilizers. Interlaboratory studies showed the accuracy of the method to be ± 6.2% for both water- and acid-soluble S, independent of the measurement wavelength, instrument, and operator.
Two-Day Hydrophobic Grid Membrane Filter Method for Yeast and Mold Enumeration in Foods Using YM-11 Agar: Collaborative Study
Authors: Entis Phyllis ,   Collaborators:, Athar A , Ballenger M , Bendeck M S , Birbari W , Brock G , Curiale M S , Estvander J , Fung D Y C , Green K , Ingham S C , Jafary M M , Jagow J A , Kalinowski R , Kelley G , Lee Y J , Lerner I , Lin C C S , Mendenhall C K , Tomer J , Reyes D , Rivera G , Rudolph C , Ryu J-H , Sado P , Snider J , Soto-Lopez L , Thakur R A H , Watson J , White S A , Wilkin E , Williams W D
Published: February 2020

Twenty laboratories participated in a collaborative study to validate a 2-day hydrophobic grid membrane filter method using YM-11 agar for enumeration of yeast and mold in foods. Six naturally contaminated food products were included in the study: garlic powder, raw ground beef, walnuts, flour/meal, orange juice, and yogurt. The test method produced significantly higher results than the 5-day pour plate reference method for orange juice and significantly lower, though numerically similar, results for walnuts and yogurt. Differences between the test and reference methods were not significant for garlic powder, raw ground beef, or flour/meal. Repeatability and reproducibility were similar for both the test and reference methods in all cases. The hydrophobic grid membrane filter method for enumeration of yeast and mold in foods has been adopted by AOAC INTERNATIONAL.
Immunoenzymatic Detection of Staphylococcal Enterotoxins: International Interlaboratory Study
Authors: Lapeyre Christiane , De Solan Marie-Noelle , Drouet Xavier
Published: February 2020

An international interlaboratory study was performed by 13 laboratories to validate a commercially available, rapid enzyme immunoassay for detection of staphylococcal enterotoxins A, B, C, D, and E in foods. The 5 enterotoxin serotypes were detected at a level of 0.5 ng/g in mushrooms and ravioli, 0.8 ng/g in meat, 1 ng/mL in milk, and 1.5 ng/g in raw milk cheese when these foods were artificially contaminated with enterotoxin A. Enterotoxins A, B, C, D, or E were also detected in culture supernatants with no protein A interference when normal rabbit serum was used. This method was validated by the French Normalization Agency for the identification of staphylococcal enterotoxins in foods and culture fluids.
Liquid Chromatographic Determination of Patulin in French Apple Ciders
Authors: Herry Marie P , Lemétayer Nicole
Published: February 2020

A liquid chromatographic (LC) method was developed for detection and quantitation of patulin in French apple ciders. Cider was applied to an Extrelut column; patulin was extracted with ethyl acetate- toluene, and the extract was cleaned up on a Sep-Pak Florisil cartridge. Patulin was detected with a UV photometer at 275 nm. A reversed-phase column and an elution gradient were used for LC separation. Patulin recoveries at 3 levels ranged from 90.4 to 91.7%. Repeatability at 50 and 100 ppb levels did not exceed 15%. The calibration graph was rectilinear from 0.2 to 1 μg/mL patulin working solutions corresponding to 20-100 ppb patulin in sample. The quantitation limit was 10 ppb. The method represents an improvement in selectivity for determination of patulin in a specific matrix such as French apple cider.
Liquid Chromatographic Determination of Fish Decomposition Indexes from Analyses of Plaice, Whiting, and Herring
Authors: Vallé Michel , Malle Pierre , Bouquelet Stephane
Published: February 2020

A simple and rapid liquid chromatographic (LC) method was used for simultaneous determination of ammonia, cadaverine, histamine, methylamine, putrescine, spermidine, spermine, tryptamine, and tyramine. These amines were separated as dansyl chloride derivatives in 22 min on a reversed-phase LC column using a binary elution gradient (water and acetonitrile). Three species of fish (plaice, whiting, and herring) stored in ice at 0C were analyzed to determine new decomposition indexes (ratios), which are less species-dependent than measurements of total volatile basic nitrogen (TVBN), trimethylamine (TMA), and P % (TMA/TVBN).
Determination of Total Avermectin B1 and 8,9-Z-Avermectin B1 Residues in Wine by Liquid Chromatography
Authors: Cobin Janice A , Johnson Nelson A
Published: February 2020

A liquid chromatographic method was developed and validated for determination of avermectin Bi and 8,9-Z-avermectin B1 residues in wine. The sample is extracted with hexane-acetonitrile and the hexane layer containing the avermectins is concentrated/ purified on an aminopropyl solid-phase extraction (SPE) column. The purified extract is derivatized with trifluoroacetic anhydride and the derivatized avermectins are analyzed by reversed-phase liquid chromatography with fluorescence detection. Recoveries of avermectins from wine fortified with approximately 1-25 ng/g avermectin B1a or 8,9-Zavermectin B1a averaged 88 and 102%, respectively. The limit of quantitation is 1 ng/g (signal-to-noise ratio [S/N] > 10) and the limit of detection is 0.5 ng/g (S/N > 3) for each analyte. This procedure provides a simple, rapid, and sensitive method for monitoring the total amount of avermectin residues in wine.
Determination of Alkali and Alkaline Earth Metals in Aceto Balsamico Tradizionale di Modena by Flame Atomic Absorption Spectroscopy
Authors: Corradini Fulvio , Franchtni Giancarlo , Marchetti Andrea , Preti Carlo
Published: February 2020

An atomic absorption spectroscopic method is proposed for determination of alkali and alkaline earth metals in Aceto Balsamico Tradizionale di Modena (ABTM). Sodium, potassium, magnesium, and calcium were measured. Determination of these metals in the ABTM matrix can be a problem. High dilution of samples eliminates the need for mineralization.
Determination of Nine Elements in Sherry Wine by Inductively Coupled Plasma-Atomic Emission Spectrometry
Authors: lópez-Artíguez Miguel , Camean Ana M , Repetto Manuel
Published: February 2020

A quick and simple method was developed to analyze various "fino" sherry wines for routine determination of Al, Ca, Cu, Fe, K, Mg, Mn, Na, and Zn content. The analysis involved heating the wine sample in an oven at 80°C to evaporate the ethanol, followed by sequential determination of the elements by inductively coupled plasma-atomic emission spectrometry. The following metal concentrations (mg/L) were obtained: Al, 1.02-4.06; Ca, 85.00-150.00; Cu, 0.06-1.62; Fe, 2.19-4.91; K, 435.02-651.65; Mg, 79.1-108.57; Mn, 0.37-2.13; Na, 27.09-54.26; and Zn, 0.12-5.08. Mean recoveries of elements from fortified wines were 101.6% for Al, 103.6% for Ca, 97.4% for Cu, 100.3% for Fe, 100.7% for K, 103.6% for Mg, 99.1% for Mn, 105.7% for Na, and 99.99% for Zn. The estimated detection limits were 15.2 μg Al/L, 39.9 μg Ca/L, 20.1 μg Cu/L, 19.1 μg Fe/L, 116.4 μg K/L, 20.3 μg Mg/L, 20.2 μg Mn/L, 34.6 μg Na/L, and 25.4 μg Zn/L. The repeatability relative standard deviation ranged from 1.1 (Mg) to 5.3% (Na), and the reproducibility relative standard deviation ranged from 2.0 (Mg) to 9.3% (Al). The results were compared with those obtained y flame atomic absorption spectrometry and, for Al, by graphite furnace atomic absorption spectrometry. By the method for regression lines we demonstrated that no differences in concentrations were obtained for any of the elements assayed. The proposed method is rapid and simple, needs only a small amount of sample, and has acceptable analytical characteristics.
Extraction Methods for Recovery of Volatile Organic Compounds from Fortified Dry Soils
Authors: Minnich Marti M , Zimmerman John H , Schumacher Brian A
Published: February 2020

Recovery of 8 volatile organic compounds (VOCs) from dry soils, each fortified at 800 ng/g soil, was studied in relation to the extraction method and time of extraction. Extraction procedures studied on 2 desiccator-dried soils were modifications of EPA low- and high-level purge-and-trap extractions (SW-846 Method 5030A): treatment 1, unmodified low-level procedure; treatment 2,18 h water presoak followed by low-level procedure; treatment 3, 24 h methanol extract at room temperature followed by high-level procedure; and treatment 4, 24 h methanol extract at 65°C followed by highlevel procedure. VOC recoveries from replicate soil samples increased in the treatment order 1 through 4. With Charleston soil (8% clay and 3.8% organic carbon), highly significant differences (p ≤ 0.001) in recoveries among treatments were observed for trichloroethene (TCE), tetrachloroethene (PCE), toluene, ethylbenzene, and o-xylene, with 2- to 3- fold increased recoveries between treatments 1 and 3. With Hayesville soil (32% clay and 0.2% organic carbon), significant improvements (p ≤ 0.05) in recoveries of toluene, ethylbenzene, o-xylene, 1,1,1-trichloroethane, TCE, and PCE were observed for heated methanol (treatment 4) rather than water extraction (treatment 1), but the increases were less than 2-fold.
Screening of Nonfatty Fish for Organochlorine Pesticide Residues by Solid-Phase Extraction Cleanup: Interlaboratory Study
Authors: Schenck Frank J
Published: February 2020

Six U.S. Food and Drug Administration laboratories participated in an interlaboratory trial of a solidphase extraction cleanup method for determination of pesticides in nonfatty seafood products. The participants analyzed control and fortified (about 0.050 ppm lindane, heptachlor epoxide, p,p′-DDE, and endrin) croaker and flounder samples and a sea trout sample containing incurred p,p′-DDE residues. Mean recoveries of the fortified residues from the fish ranged from 89.1 to 107.8%. The within-laboratory coefficients of variation (CVs) ranged from 4.2 to 8.5%, and the among-laboratory CVs ranged from 10.9 to 26.5%. The 6 laboratories reported a mean value of 0.040 ppm p,p′-DDE in a fish sample which contained incurred residues. The same value (0.040 ppm) was obtained by using official methodology. The within-laboratory CVs ranged from 3.5 to 18.3%, and the among-laboratory CV was 17.3%.
Rapid Determination of Imazapyr in Corn by Gas Chromatography/Mass Spectrometry with Electron Capture Negative Ion Chemical Ionization
Authors: Stout Steven J , Dacunha Adrian R , Fletcher J Shahn , Picard Gerald L
Published: February 2020

Imazapyr, an imidazolinone class herbicide, was developed recently for weed control in imidazolinonetolerant corn. Current methods for determining imidazolinone herbicides in crops involve laborious, time-consuming cleanup procedures after extraction. We developed an extremely simple cleanup procedure for imazapyr in corn commodities after extraction with acidic acetone-water by using gas chromatography/mass spectrometry with electron capture negative ion chemical ionization for final detection. Method sensitivity was 50 ppb, with controls showing <5 ppb. Average recoveries from corn forage, fodder, and grain were 98,106, and 101%, respectively.
Physicochemical Data for Some Selected Fusarium Toxin
Authors: Sydenham Eric W , Thiel Pieter G , Vleggaar Robert
Published: February 2020

Fusarium toxins are a major group of secondary metabolites, produced by several species, that may contaminate food cereals and animal feeds. We describe results of a study in which a number of physicochemical constants for 12 important Fusarium mycotoxins (zearalenone, diacetoxyscirpenol, T-2 toxin, neosolaniol monoacetate, deoxynivalenol, nivalenol, fumonisin B1, fumonisin B2, moniliformin, fusarenon-X, HT-2 toxin, and β-zearalenol) were determined. Nuclear magnetic resonance, mass spectrometric, UV spectral, molar absorption coefficients, fluorescence spectra, melting points, and specific rotation data are presented.
Determination of Carbohydrates in Soluble (Instant) Coffee by Anion-Exchange Chromatography with Pulsed Amperometric Detection: Summary of Collaborative Study
Authors: Prodolliet Jacques , Bugner Emmanuel , Feevberg Max
Published: February 2020

A collaborative study was conducted to validate a liquid chromatographic (LC) method for determining free and total (after acid hydrolysis) carbohydrate profile of soluble (instant) coffee. Carbohydrates were separated on a pellicular anion-exchange column with pure water as mobile phase and detected by pulsed amperometry. Precisions in determining free and total carbohydrates were very similar. Average RSDr and RSDR values were 4.5 and 14.3%, respectively, for carbohydrate levels >0.3%, with individual values ranging, respectively, from 2.2 to 4.6% and 9.9 to 24.2% for mannitol, 1.6 to 7.3% and 4.9 to 21.1 % for arabinose, 1.7 to 8.1 % and 4.1 to 12.9% for galactose, 2.4 to 8.7% and 6.1 to 24.3% for glucose, 1.8 to 6.8% and 10.0 to 11.6% for sucrose, 3.7 to 7.4% and 22.5 to 27.8% for xylose, 2.0 to 7.0% and 10.6 to 24.4% for mannose, and 2.9 to 5.2% and 15.5 to 18.4% for fructose (free form only). The technique's precision was considered good, taking into account the usual peak integration problems always encountered in LC procedures, the low levels of free carbohydrates, the hydrolysis step, and the relative lack of experience of most participating laboratories. Except for the pair rhamnose/arabinose, the method allows good and reproducible separation of carbohydrates found in soluble coffee and, therefore, is suitable for routine analysis. The anion-exchange chromatographic method with pulsed amperometry for determining carbohydrates in soluble (instant) coffee has been adopted first action by AOAC INTERNATIONAL.
Determination of Total Phosphorus in Foods by Colorimetry: Summary of NMKL Collaborative Study
Authors: Pulliainen T Katrhna , Wallin Harriet C
Published: February 2020

A collaborative study was conducted to validate a spectrophotometric–colorimetric method for determining total phosphorus in foods. The sample was dry-ashed in the presence of zinc oxide, and total phosphorus content was measured colorimetrically as molybdenum blue. Twelve laboratories from the Nordic countries participated in the study. The test materials included potato flour, sausage, cold ham, infant formula powder, cheese, and skimmed milk powder. Participants received 12 randomly coded samples of 2 blind duplicates of each material. Phosphorus contents of materials varied between 0.076 and 0.96 g/100 g. Relative standard deviations for repeatability of the method varied from 1.1% for 0.96 g phosphorus/100 g to 5.4% for 0.29 g phosphorus/100 g. Relative standard deviations for reproducibility varied from 3.6% for 0.96 g phosphorus/100 g to 7.7% for 0.23 g phosphorus/100 g. The colorimetric method for determination of total phosphorus in foods has been adopted first action by AOAC INTERNATIONAL as an NMKUAOAC INTERNATIONAL method.
Determination of Ttace Levels of Dichlorprop, Mecoprop, Clofibric Acid, and Naphthylacetic Acid in Soil by Gas Chromatography/Mass Spectrometry with Selected-Ion Monitoring
Authors: Heberer Thomas , Stan Hans-Juergen
Published: February 2020

A sensitive analytical method was developed for determining trace levels of dichlorprop, mecoprop, clofibric acid, and naphthylacetic acid in soil samples. The method applies extraction with acetone and aqueous acetic acid followed by solid-phase extraction as the first cleanup step. After target analytes are derivatized with pentafluorobenzyl bromide, they are determined by capillary gas chromatography (GC)/mass spectrometry with selectedion monitoring. Further cleanup of sample extract by gel permeation chromatography prevented the GC system from being contaminated with matrix compounds, although in most cases, it was not necessary. Limits of detection and quantitation as low as 0.1 and 1 ppb, respectively, were achieved. Recoveries of all analytes were >90%, with relative standard deviations of <10%.
Effect of Household Preparation on Levels of Pesticide Residues in Produce
Authors: Schattenberg Herbert J , Geno Paul W , Hsu J P , Fry William G , Parker Richard P
Published: February 2020

In 1993, the National Academy of Sciences released a report on the effects of pesticides in the diets of infants and children, indicating that current tolerances do not take into account the eating habits and metabolism of young children. In response to that report, a study was undertaken to determine pesticide residues in raw agricultural commodities at levels below the tolerances established by the Environmental Protection Agency. The objective of the study was to determine whether normal household washing, peeling, and cooking procedures had any effect on pesticide residue levels. Low levels of pesticide residues were detected in 97 (40%) of the 243 samples analyzed. The number of samples containing detectable residues dropped to 47 (19%) after household preparation. Results indicate that residue levels in most commodities are substantially reduced after household preparation.
Florisil Solid-Phase Extraction Cartridges for Cleanup of Organochlorine Pesticide Residues in Foods
Authors: Schenck Frank J , Calderon Lori , Saudarg Darlene E
Published: February 2020

Florisil solid-phase extraction cartridges were evaluated for cleanup of organochlorine pesticide residues in food extracts. Elution patterns and recoveries were determined for 24 organochlorine pesticides. A range of elution solvents was evaluated. A 2% ethyl ether–petroleum ether eluant optimized overall recoveries while minimizing interferences from coextractants.
Electrophoretic Identification of Garlic and Garlic Products
Authors: Mochizuki Emiko , Yamamoto Takao , Suzuki Sumiko , Nakazawa Hiroyuki
Published: February 2020

We developed a rapid and simple method for identifying garlic and garlic products using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) with silver staining. Samples were homogenized with 1 % SDS or 6M urea and centrifuged. Supernatant containing garlic proteins was mixed with the same volume of loading buffer containing SDS and mercaptoethanol, heated in boiling water for 2 min, and applied to the wells of a ready-to-use polyacrylamide gradient gel (4–20%). Electrophoresis was performed 20 mA constant current for 2 h. The gel was stained with a silver staining kit and dried. Protein patterns of garlic and garlic products are different from those of other Allium plants such as onion, rakkyo, and caucas. The method was used to analyze samples of spice and garlic clove products. Absence of protein bands in garlic extract products suggests the products may contain less proteins and/or denatured proteins.
Determination of Antifungals in Rodent Diet by Supercritical Fluid Extraction Followed by Packed Column Supercritical Fluid Chromatography with Ultraviolet Detection
Authors: Dean John R , Fowlis Ian A , Hitchen Stephen M , Khundker Sharmin , Ludkin Edwin , Normand Florence , Jones Peter
Published: February 2020

Supercritical fluid extraction (SFE) followed by packed column supercritical fluid chromatography with ultraviolet detection was evaluated as a quantitative method for determining 4 antifungals (fluconazole, tioconazole, hexaconazole, and UK- 47,265) in rodent diet. Chromatography was achieved with a cyano-bonded silica column, UV detection at 210 nm, and methanol-modified supercritical carbon dioxide as mobile phase. The effects of modifier concentration, temperature, and column pressure on antifungal retention time was studied. Off-line SFE was optimized at 2 spike levels, ranging from 0.5 to 10 g/kg, for each of the 4 antifungals. Average recoveries ranged from 79.0% for UK-47,265 to 96.5% for hexaconazole. Overall, the procedure provides a suitable method for analyzing antifungals in spiked rodent diet.
Investigation of Assay Interference with Microbiological Determinations of Chlortetracycline in Feed Grade and Premix Samples
Authors: Webster Gregory K , Luigs Elizabeth S , Hearne Loretta A , Pomeroy Margaret , Panozzo Linda A , Bell Jim , Mustapha Mustapha A
Published: February 2020

Studies were initiated to determine whether tetracycline components such as tetracycline and 4-epichlortetracycline present in commercial feed grade chlorteracycline (CTC) products interfere with AOAC Method 967.39. These investigations confirmed that the microbiological result for feed grade concentrates and premix products is not affected by the biomass matrix containing low levels of these other tetracycline components. Thus, the microbiological result can be directly correlated to the single CTC peak response in liquid chromatographic analytical procedures.
Liquid Chromatographic Determination of Scopolamine, Hyoscyamine, and Phenobarbital in Tablets
Authors: Ting Susan
Published: February 2020

A liquid chromatographic method using a reversed- phase C18 column and octanesulfonic acid sodium salt-methanol as the mobile phase was developed for the simultaneous determination of phenobarbi- tal, scopolamine, and hyoscyamine in tablets. The mixture of the 3 drugs was resolved in <8 min. Detector responses were linear for 10 μL injections of the following: scopolamine hydrobromide, 8.25-206.3 μg/mL; hyoscyamine sulfate, 15.01-750.76 μg/mL; and phenobarbital, 250-751 μg/mL. Recoveries from tablets were 100.8% for scopolamine hydrobromide, 100.1% for hyoscyamine sulfate, and 100.3% for phenobarbital. Replicate injections of scopolamine hydrobromide, hyoscyamine sulfate, and phenobarbital gave an overall relative standard deviation of <1.0% (n = 10). The method detected as little as 3.3 ng scopolamine hydrobromide.
Evaluation of Commercial Chlorophyllin Copper Complex Preparations by Liquid Chromatography with Photodiode Array Detection
Authors: Chernomorsky Simon , Rancourt Raymond , Sahai Divya , Poretz Ronald
Published: February 2020

A reversed-phase liquid chromatographic (LC) system with photodiode array detection was used to analyze chlorophyllin copper complex (CCC). Analysis revealed significant differences in the porphyrin compositions of CCC samples from 5 industrial sources. Copper isochlorin e4 was identified as a major component in most commercial materials. Copper complexes of chlorin e6 and pheophorbide a and unidentified porphyrins with either chlorin- or non-chlorin-type spectra were found in some samples. The variability of porphyrin compositions in commercial preparations may affect the medicinal efficacy of CCC; therefore, analysis of porphyrin composition is important for CCC quality control.
Optimizing the Determiniaton of Trypsin Inhibitor Activity in Chickpeas by Response Surface Methodology
Authors: Martínez-Domínguez Beatríz , Rincón-León Francisco
Published: February 2020

Response surface methodology (RSM) was used to optimize determination of trypsin inhibitor activity (TIA) in chickpea. TIA was determined by measuring the hydrolysis rate of N-α-benzoyl-DL-arginine-p- nitroanilide hydrochloride (BAPNA) in the presence of both pig pancreatic trypsin (EC 3.4.21.4) and chickpea extract containing trypsin inhibitor. Three critical parameters in TIA determination—buffer extraction pH (pH), stirring extraction time (Set), and development color time (Dct)—were optimized. Highest TIA values were obtained when pH = 11, Set = 150 min, and Dct = 10.2 min.
Determination of Long-Life Radiocesiums Cs-134 and Cs-137 in Food by γ-Ray Spectrometry: Summary of Collaborative Study
Authors: Beuaars Paul R , Van Duk Remmelt , Geertsen Jos A M , Nootenboom Hans
Published: February 2020

A collaborative study was conducted to validate a γ- ray spectrometric method for determining cesium- 134 and cesium-137 in foods. The Cs-134 and Cs- 137 contents are measured with a low-resolution, shielded Tl-activated Nal scintillation detector connected to a multichannel γ-ray spectrometer. Thirteen laboratories participated in the study. Participants received 8 samples of heather honey, milk, and mixed dried herbs, including 4 blind duplicates. The accuracy of mean measurements of both isotopes was in the range of 98 to 103%, compared with reference measurements made in one laboratory using a high-resolution GeLi detector. Repeatability relative standard deviation (RSDΓ) values varied from 4.3 to 11.7% for 2 Cs-134 levels ranging from 121 to 337 Bq/kg and from 2.0 to 7.3% for 4 Cs-137 levels ranging from 210 to 1130 Bq/kg. Reproducibility relative standard deviation (RSDr) values ranged from 10.7 to 14.9% for Cs-134 and from 4.1 to 7.4% for Cs-137. No outliers were identified, and the method worked well in the absence of “fresh” fission products. However, the method was less appropriate for radiocesium determinations for activity concentration <100 Bq/kg at a counting time of 900 s or when Cs-137/Cs-134 activity ratio was larger than 10. The γ-ray method for determining Cs-134 and Cs-137 in foods has been adopted first action by AOAC INTERNATIONAL.
Enzymatic Determination of Lactose and Galactose in Foods: NMKL Collaborative Methods Performance Study
Authors: Mustranta Antti , Östman Carola ,   Collaborators:, Aminoff I , Baardseth P , Eklund E , Jokila T , Kähäri K , Larsson B , Malmheden Yman I , Nyberg K , Pihlaja H , Sørensen A , Sørhaug T , Östman C
Published: February 2020

Enzymes are widely used in food chemistry as analytical tools. An enzymatic method for determining lactose and galactose in foods was evaluated in an interlaboratory methods performance study by 12 laboratories in 4 countries. The method is based on enzymatic hydrolysis of lactose and enzymatic oxidation of the hydrolysis products. The exchange of the coenzyme in the second reaction is the basis of quantitation. The method may be used for various types of foods, such as liquid and solid milk products, meat products, cereal products, fats, dressings, sweets, chocolate, and foods for special dietary uses. It is also applicable to lactose-free foods but not to products in which lactose has been partially hydrolyzed enzymatically to glucose and galactose. Six commonly used foodstuffs with lactose concentrations ranging from 0.4 g/100 g to 40 g/100 g and galactose concentrations up to 0.7 g/100 g were analyzed: crisp rye bread, milk chocolate, sausage, cheese, margarine, and baby food containing milk powder. They were distributed to the 12 participants as 12 randomly numbered test samples, representing blind duplicates of the 6 materials. The relative standard deviations for reproducibility (RSDR) were between 2.3-11% for lactose and 6.8-50% for galactose.
Determination of Sugars in Beet and Cane Final Molasses by Ion Chromatography: Collaborative Study
Authors: Schäffler Kevin , Day-Lewis C M J , Clarke Margaret , Jekot Jill ,   Collaborators:, Rearick E , Tungland B , Steinle G , Edye L , Morel du Boil P , Ramphal E , Deruy G , Hoebregs H , Parslow B , Liecker H , Jekot J
Published: February 2020

A collaborative study of an ion chromatographic tech’ nique of high-performance anion-exchange with pulsed amperometric detection has been completed. The procedure was used to determine sucrose, glucose, and fructose in 8 cane molasses samples and sucrose in 5 beet molasses samples. Eleven laboratories took part in the study. Repeatability and reproducibility values for sucrose, glucose, and fructose were excellent for both types of samples. All criteria for accepting the method for sugars in both beet and cane molasses were met. The ion chromatographic method for determination of sugars in beet and cane final molasses has been adopted first action by AOAC INTERNATIONAL.
Rapid Liquid Chromatographic Method to Distinguish Wild Salmon from Aquacultured Salmon Fed Synthetic Astaxanthin
Authors: Turujman Saleh A , Wamer Wayne G , Wei Rong Rong , Albert Richard H
Published: February 2020

Analytical methods are needed to determine the presence of color additives in fish. We report a liquid chromatographic (LC) method developed to identify the synthetic form of the color additive astaxanthin in salmon, based on differences in the relative ratios of the configurational isomers of astaxanthin. The distributions of configurational isomers of astaxanthin in the flesh of wild Atlantic and wild Pacific salmon are similar, but significantly different from that in aquacultured salmon. Astaxanthin is extracted from the flesh of salmon, passed through a silica gel Sep-Pak cartridge, and analyzed directly by LC on a Pirkle covalent L-leucine column. No derivatization of the astaxanthin is required—an important advantage of our approach, which is a modification of our previously described method. This method can be used to distinguish between aquacultured and wild salmon. The method has general applicability and can also be used to identify astaxanthins derived from other sources such as Phaffia yeast and Haematococcus pluvialis algae.
Determination of O-Phenylphenol, Diphenylamine, and Propargite Pesticide Residues in Selected Fruits and Vegetables by Gas Chromatography/Mass Spectrometry
Authors: Yu Lei , Schoen Royal , Dunkin Arlene , Firman Michael , Cushman Holly , Fontanilla Alfredo
Published: February 2020

A simple and rapid method was developed to detect o-phenylphenol, diphenylamine, and propargite in selected fruits and vegetables. Gas chroma- tography/mass spectrometry in the selective-ion monitoring mode was used to identify and quantitate the 3 residues. Residues were extracted with acetonitrile and transferred to acetone. Limits of detection were 10, 8, and 15 ppb for o-phenylphenol, diphenylamine, and propargite, respectively. Recovery data were obtained by fortifying 4 matrixes (apples, oranges, canned peaches, and spinach) at 0.025-0.888 ppm. The method provides very good linearity data with low coefficients of variation.
Chemometric Protocol to Validate an Analytical Method in the Presence of Corrigible Constant and Proportional Systematic Errors
Authors: Campaña Ana M García , Rodríguez Luis Cuadros , Muñoz Juan Aybar , Barrero Fermín Ales
Published: February 2020

A statistical methodology to verify the trueness of an analytical method in the presence of corrigible systematic errors is presented. This protocol enables detection of constant and proportional components of error. By using the data set obtained in the Youden calibration with different sample test portions, the constant component of the error (Youden blank) can be determined. An analysis of covariance was applied to 3 calibration curves established with standard solutions and with standard additions to 2 different sample test portions. The slopes were compared, and the presence of any matrix-analyte interaction was detected. A method for removing the numerical components of systematic errors is proposed: a calculation procedure to obtain a correct analytical result and a statistical test to verify the correctness of analyte contents obtained from different calibrations. For demonstration purposes, the protocol was applied to spectrofluorometric determination of oxalates in spinach leaves.
Quantitation of Tebuconazole in Liquid and Solid Formulations by Capillary GC: Collaborative Study
Authors: Harbtn Donald N ,   Collaborators:, Amleh A , Bernes A , Bodzian F , Boyer K , Conaway J , Dias H , Dommarco R , Duverney-Pret P , Earnest S , Ely D , Fornarelli L , Förster R , Gentry G , Görlitz G , Gomez F , Guess P , Hähnchen K , Hamilton D , Halley M , Hathaway M , Hickes H , Isono K , Kulinna H , Lucas P , Manger P , Manso L , Moffett S , Müller T , Orii T , Paul R , Reubke K , Rivera L , Rubbiani M , Schetter J , Schulz D , Shaocong L , Smead F , Tam K , Tengler H , Torma L , del Valle M , Verweij A , Walls G , Weiping G
Published: February 2020

A capillary gas chromatographic method has been developed for quantitation of tebuconazole (Folicur, Elite, Raxil, Lynx) in liquid and solid formulations. Tebuconazole is a broad-spectrum, systemic foliar fungicide used to control diseases of wheat, barley, peanut, and grasses grown for seed. Samples are dissolved in acetone and analyzed by capillary gas chromatography (GC) with dicyclohexyl phthalate as internal standard. Twenty-two laboratories from 11 countries participated in a collaborative study of the method. Each collaborator was provided reference standard, internal standard, and blind duplicate samples from 6 formulations: aqueous flowable (F), aqueous emulsifiable concentrate (EW), emulsifiable concentrate for seed treatment (ES), flowable for seed treatment (FS), wettable powder (WP), and dry flowable (DF). Collaborators were instructed to use peak area measurements for quantitation. The seed treatment flowable formulation required confirmation of accurate integration values by the collaborator. Relative standard deviation values for reproducibility (RSDR) for analysis of the formulations were as follows: 3.6 lb/gal F, 1.22; 250 g/L EW, 1.13; 15 g/L ES, 2.40; 25 g/L FS, 2.65; 25% WP, 0.96; 25% DF, 0.72; 45% DF, 0.72. The capillary GC method for quantitation of tebuconazole in fungicide formulations has been adopted first action by AOAC INTERNATIONAL.
Liquid Chromatographic Analysis of Bacitracin Methylene Disalicylate in Feed
Authors: Webster Gregory K
Published: February 2020

Because of its peptide structure, bacitracin is not chemically distinct from many matrixes such as feeds or residue samples. Thus, bacitracin must be isolated from the matrix components or chemically altered to form a distinct component. Because of the complexity of this problem, bacitracin is still analyzed almost exclusively by microbiological methods. However, advances in solid-phase extraction has made sample isolation from the matrix much more practical. In this investigation both strong-cation exchange and C8 columns were used to isolate bacitracin for liquid chromatographic (LC) analysis. Results of both LC and microbiological analyses are compared.
Simple Kinetic Method for Assay of Menadione In Pharmaceuticals
Authors: Helaleh Murad I H
Published: February 2020

A new simple and sensitive kinetic method for determining menadione in pure form and injection form is described, based on the reaction between menadione and sodium hydroxide to form a colored complex with a strong absorbance at 450 nm. The method is valid for determining menadione at concentrations ranging from 5.807 × 10-1 to 7.549 × 10 3 M. The complex forms at a 2:3 concentration ratio of menadione with respect to sodium hydroxide. The formation constant is 8.37 × 1015, and the molar absorptivity is 6.55 × 102 L/mol cm. The precio sion and accuracy of the method and the effect of interfering substances were studied. Results were compared with those obtained with an official method.
Visual Immunoprecipitate Assay (VIP) for Listeria monocytogenes and Related Listeria Species Detection in Selected Foods: Collaborative Study
Authors: Feldsine Philip T , Lienau Andrew H , Forgey Robin L , Calhoon Roger D ,   Collaborators:, Al-Hasani S , Arling V , Bandiera T , Barnes M , Beatty S , Beaudoin A , Beyer D , Bryant J , Burzynski M , Carey B , Copeland F , Culver D , Danisavich T , Destro C , Diaz B , Fitzgerald S , Gallagher D , Franke W , Freshly J , Gary J , Harper M , Hermann C , Isakson T , Jenkins P , Johnson S , Ke J , Krause C , Lange K , Maki G , McDonagh S , McKee B , McLenaghan J , Miller L , Phebus R , Raghubeer E , Redding R , Retzlaff D , Richter D , Ritger C , Robinson J , Saunders L , Schwants D , Trottier Y , Tuncan E , Vanderbilt K , Ward D , West D , Woo L , Zebchek A
Published: February 2020

Six foods representing a variety of food products were analyzed by the Assurance Listeria polyclonal enzyme immunoassay (EIA) and by either the Bacteriological Analytical Manual or the U.S. Department of Agriculture culture method for detecting Listeria monocytogenes and related Listeria species. Samples of each food type, at each inoculation level, were analyzed simultaneously by both methods. A total of 19 laboratories representing federal government agencies and private industry in the United States and Canada participated. Food types were inoculated with Listeria species including L. monocytogenes, with the exception of 3 lots of green beans, which were naturally contaminated. During this study, 1764 samples and controls were analyzed and confirmed, of which 492 were positive and 947 were negative by both methods. There were 159 samples that were positive by culture method but negative by the EIA and 188 that were negative by culture method but positive by EIA. Twenty-two samples were negative by EIA and by culture method but confirmed positive when Assurance selective enrichment broths were subcultured to selective agar. The Assurance polyclonal EIA for detecting L. monocytogenes and related Listeria species in foods has been adopted first action by AOAC INTERNATIONAL.