bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid Chromatographic Determination of Atropine in Nerve Gas Antidotes and Other Dosage Forms
Authors: Lehr Gary J , Yuen Stella M , Lawrence Glen D
Published: February 2020

A simple and specific liquid chromatographic method was developed for the determination of atropine in nerve gas antidotes and several other dosage forms. The method is also used simultaneously to quantitate phenol, an antimicrobial agent present in nerve gas antidotes, and to monitor the level of tropic acid, a principal degradation product of atropine. The system uses a Spherisorb CN column and a mobile phase of acetonitrile–0.05M sodium phosphate monobasic (10 + 90), pH 4.0. The detection wavelength is 220 nm. The method was validated by testing for accuracy, linearity, reproducibility and precision. In addition, the proposed method was applied to 8 commercial preparations of atropine, including injectables, ophthalmic solutions, and ointments, and was found to be satisfactory and free from interferences from preservatives, such as benzyl alcohol, methylparaben, benzalkonium chloride and chlorobutanol, that are present in these formulations.
Determination of Sulfadimethoxine Withdrawal Time from Milk. Part I: Dosing, Sampling, and Assay
Authors: Weiss George , Laurencot Henry J , Macdonald Alexander , Duke Paul D , Misra Kabita , Horton Glyn M , Katz Stanley E , Brady Marietta Sue
Published: February 2020

This study was undertaken to determine whether present regulations for discarding milk from cows treated with sulfadimethoxine (SDM) can be supported by modern analytical methodology. Two groups of milking cows (10 in first group; 11 in the second) were treated orally with SDM at the recommended dose levels for 5 days. The SDM concentration in the milk was determined with 4 methods (Charm Inhibition Assay [CIA], Charm II, enzyme linked immunosorbent assay, and liquid chromatography) during the treatment and the subsequent withdrawal periods. The results of the 4 assays were compared.
Relative Effectiveness of Selenite Cystine Broth, Tetrathionate Broth, and Rappaport-Vassiliadis Medium for the Recovery of Salmonella from Raw Flesh and Other Highly Contaminated Foods: Precollaborative Study
Authors: June Geraldine A , Sherrod Patricia S , Hammack Thomas S , Amaguana R Miguel , Andrews Wallace H
Published: February 2020

The effectiveness of selenite cystine (SC) broth, tetrathionate (TT) broth, and Rappaport-Vassiliadis (RV) medium for recovery of Salmonella spp. from 8 highly contaminated foods was determined. RV medium prepared from individual ingredients and incubated at 42° and 43°C was compared with 2 commercial (Difco and Oxoid) media incubated at 42°C. Naturally and artificially contaminated foods were tested under 2 protocols. For Protocol 1, each food was preenriched in the appropriate medium. After incubation, serial 10 fold dilutions of the preenriched foods were inoculated into selective enrichment media and incubated at 35°, 42°, or 43°C. Effectiveness of these conditions was evaluated by most probable number determination of Salmonella spp. recovered. Productivity of selective enrichments did not differ significantly with this protocol, except that with Oxoid RV medium the number of Salmonella cells recovered from most of the foods was significantly reduced. For Protocol 2, twenty 25 g test portions from artificially inoculated foods were examined qualitatively for Salmonella spp. The effectiveness of the broth/temperature combinations was determined by the number of positive tests under each condition. RV medium prepared from individual ingredients and TT broth incubated at 43°C yielded significantly more Salmonella-positive tests from frog legs and lettuce than did SC and TT broths incubated at 35°C or commercial RV medium incubated at 42°C. With pork sausage and ground beef, significantly fewer Salmonella-positive tests were found with Oxoid RV medium incubated at 42°C and SC incubated at 35°C than from other selective enrichments. With chicken, fewer Salmonella-positive tests were found from SC and TT broths incubated at 35°C and Oxoid RV medium incubated at 42°C than from other selective enrichments. There were no significant differences among selective enrichments in the recovery of Salmonella spp. from the remaining foods. Overall, RV prepared from individual ingredients and incubated at 42°C yielded the highest number of Salmonella-posWive tests.
Liquid Chromatographic Method for Rapid Determination of Total Avermectin B1 and 8,9-Z-Avermectin B1 Residues in Apples
Authors: Cobin Janice A , Johnson Nelson A
Published: February 2020

A liquid chromatographic method has been developed and validated for the rapid determination of avermectin B1 and 8,9-Z-avermectin B1 residues in apples. The avermectins are extracted from the crop matrix with an acetonitrile–water–hexane mixture; the extract is cleaned up on an aminopropyl solid-phase extraction column. The avermectins are derivatized with trifluoroacetic anhydride and analyzed by reversed-phase liquid chromatography with fluorescence detection. Recoveries of avermectins from apples fortified with about 2–77 ppb avermectin B1a or 2-27 ppb 8,9-Z-avermectin B1a averaged 85%. The limit of quantitation is 2 ppb (signal- to-noise [S/N] ratio, 12) and the limit of detection is 1 ppb (S/N ratio, 6) for each analyte. The assay is a simple, rapid, and sensitive method for monitoring the total amount of avermectin residues in apples.
Extraction of Lipid-Soluble Marine Biotoxins
Authors: Hannah Donald J , Till Desmond G , Deverall Terry , Jones Paul D , Fry Joanne M
Published: February 2020

A recent extensive outbreak of toxic shellfish poisoning (TSP) in New Zealand, with at least 4 types of toxicities present, required the development of a new method for detecting lipid-soluble marine biotoxins. The complexity of studying this outbreak, requiring large sample numbers, dictated the development of a robust and safe method for extracting lipid-soluble toxins. The new method is based on extraction of lipophilic compounds with acetone followed by partitioning into dichloromethane. The dichloromethane extract is evaporated to constant weight and suspended in a detergent–saline solution for use in a mouse bioassay. The new method produces an extract of superior quality, is quicker and more sensitive compared with extraction methods currently used.
Four-Laboratory Validation Study of the Determination of Chloramphenicol in Veal Calf Urine
Authors: Holland Kathleen P , Henry A Carolyn , Wilson T Roger , Dreas S John , Ashworth B Raymond
Published: February 2020

A four-laboratory validation study of a method for the quantitation and confirmation of low part-perbillion levels of chloramphenicol extracted from veal calf urine was done. With this method, chloramphenicol, derivatized to the bis(trimethylsilyl) ether, was quantitated by gas chromatography with electron capture detection (GC–ECD) and confirmed by selected-ion monitoring in a negative ion chemical ionization gas chromatograph-mass spectrometer (GC–NICI–MS). Four analysts from 4 laboratories participated in the portion of the study devoted to chloramphenicol quantitation. Every analyst analyzed 5 sets, one set per day, on 5 different days. Each set included 6 samples consisting of a blank, 2 fortified samples, 2 incurred urine samples, and one duplicate. Thus, each analyst worked on a total of 30 samples. Chloramphenicol concentrations ranged from 0 to 9.7 ppb. All data were reported to 0.1 ppb. Coefficients of variation for distribution, CVd, ranged from 8.82 to 14.14% and for precision, CVr, ranged from 9.15 to 14.80%. Three analysts from 3 laboratories also participated in the confirmatory portion of the study, which was carried out to test whether the NICI–MS method developed earlier for higher concentrations of chloramphenicol and for an extract of muscle tissue could be applied to lower levels of chloramphenicol and to an extract prepared from urine. The extracts of 10 of the 30 samples were designated for confirmation only, but were obtained by the same procedure as extracts used for the quantitation part of the study. The confirmation part of the study failed to determine whether NICI–MS is still valid for these levels and this matrix because source temperature lower than that recommended by the originating laboratory as used by all collaborating laboratories. The spectra generated by collaborators were different from those expected.
Determination of Boron in Fertilizers by Inductively Coupled Plasma-Atomic Emission Spectrometry: Studies of Some Spectral Interferences at Different Wavelengths
Authors: Matilainen Rose , Tummavuori Jouni
Published: February 2020

The most sensitive analytical wavelengths of boron cannot be used in the determination of boron in fertilizers by inductively coupled plasma-atomic emission spectrometry because of spectral interference by potassium, phosphorus, and iron. For the 4 wavelengths of boron investigated, it was noticed that, at the same wavelength, the pattern of spectral interference changes according to fertilizer composition. The spectral interference patterns at the 4 analytical boron wavelengths were studied by adding matrix elements typically found in fertilizers to real fertilizer samples. When levels of added matrix elements correlate less than 0.2 to each other, the effect of added matrix elements on boron determination can be calculated by multiple linear regression. The best analytical wavelength for determination of boron in fertilizer is 208.959 nm. If wavelength is selected only according to calibration data, without doing interference studies, the best wavelength should be 249.773 nm. Multiple linear regression in conjunction with experimental design may be used to determine the best analytical wavelength for a sample matrix under analysis, examine the interference elements, and verify the concentration detected.
Simultaneous Determination of Chlorothalonil and Hexachlorobenzene in Technical and Formulated Materials by Capillary Gas Chromatography
Authors: Vargyas Linda D , Walls Gregory E , Cryberg Richard L , Bramstedt William R , Wang Frank J , Mayo Hugh L , Eilrich Gary L
Published: February 2020

A capillary gas chromatographic method using flame ionization detection was developed for simultaneous assay of chlorothalonil and hexachlorobenzene in technical material and formulated products. Method precision is excellent, and the method allows simultaneous determination of one chemical impurity. The method uses an internal normalization reagent (n-butyl phthalate). Modification and extension of the method to formulated products, including wettable powders, water-based flowables, and dispersible (or dry flowable) granular formulations, are discussed. Preliminary statistical analysis of intra- and interlaboratory comparisons was performed to evaluate method ruggedness. Average relative standard deviations for technical materials were 0.34 and 0.17% from 2 laboratories. Additional method validation studies were conducted to examine the influence of pH, solvent systems, gas chromatographic systems, and temperature conditions on different formulations.
Liquid Chromatographic Fluorescence Method for Multiresidue Determination of Thiabendazole and 5-Hydroxythiabendazole in Milk
Authors: Arenas Rene V , Johnson Nelson A
Published: February 2020

A novel liquid chromatographic multiresidue method has been developed for quantitation of thiabendazole (TBZ), the metabolite 5-hydroxythiabendazole (5-OH-TBZ), and the sulfate conjugate of 5-hydroxythiabendazole (5-HSO4-TBZ) in raw cow’s milk. The 5-HSO4-TBZ is hydrolyzed quantitatively under acidic conditions to 5-OH-TBZ. TBZ and 5-OH-TBZ are extracted from milk at pH 8.0 with ethyl acetate followed by cleanup of the extract on a cation-exchange solid-phase extraction column. Analytes are quantitated by liquid chromatography with a cation-exchange stationary phase and fluorescence detection. Recoveries from raw cow’s milk samples fortified with TBZ and 5-OH-TBZ or TBZ and 5-HSO4-TBZ at 0.05 to 2 ppm ranged from 87 to 103% for TBZ, 98–109% for 5-OH-TBZ, and 96–115% for 5-HSO4-TBZ (quantitated as 5-OH-TBZ). The assay provides a simple, rapid, and sensitive multiresidue method for monitoring total residues of TBZ, 5-OH-TBZ, and 5-HSO4-TBZ in milk.
Liquid Chromatographic Determination of Tolrestat and Related Compounds in Raw Materials
Authors: Beaulieu Normand , Lacrok Pauline M , Sears Roger W , Loveremg Edward G
Published: February 2020

A liquid chromatographic method was developed for the determination of tolrestat and 7 related compounds. The lower limit of quantitation of the related compounds in the presence of the drug was <0.05%. The coefficient of variation on the assay of drug raw material analyzed on 5 different days was 0.75%. Total impurities found in 2 samples of tolrestat from different sources were 0.12 and 0.54%, respectively. The method was validated by a second laboratory.
Relative Effectiveness of Selective Plating Agars for Recovery of Salmonella Species from Selected High-Moisture Foods
Authors: Sherrod Patricia S , Amaguana Rene Miguel , Andrews Wallace H , June Geraldine A , Hammack Thomas S
Published: February 2020

The relative effectiveness of 6 selective plating media were compared for effectiveness in recovery of Salmonella spp. from selected high-moisture foods. Three new plating agars (EF-18, Rambach, and xylose lysine Tergitol-4) and 3 selective plating agars (bismuth sulfite, Hektoen enteric, and xylose lysine desoxycholate) recommended by AOAC INTERNATIONAL and the Bacteriological Analytical Manual (BAM) were compared. The agars were streaked from cultures selectively enriched in selenite cystine broth, tetrathionate broth, and Rappaport–Vassiliadis medium. The high-moisture foods studied were naturally contaminated pork sausage, chicken parts, turkey parts, and frog legs and artificially contaminated shrimp, oysters, egg yolks, and lettuce. The relative effectiveness of each selective plating agar was determined by recovery of Salmonella spp. and enumeration of false-positive and false-negative reactions. Although the new selective plating agars compared favorably with the AOAC/BAM-recom mended agars, they offered no advantage. Incubation of selective enrichment broths at elevated temperatures decreased the numbers of false-positive and falsenegative reactions for all 6 selective plating agars.
Incidence of Aflatoxins in Animal Feedstuffs: A Decade’s Scenario in India
Authors: Dhavan A S , Choudary M R
Published: February 2020

During the period 1983–1993,4818 samples of agricultural commodities, comprising cereals, oilseed cakes, compound feeds, and other ingredients, were examined for aflatoxin contamination. High quantities of aflatoxins were found in groundnut cake, deoiled groundnut cake, maize, and mixed feeds. Highest incidence of aflatoxin contamination was observed in groundnut cake (96.35%) and deoiled groundnut cake (96.20%), and the highest level of aflatoxin B1, 8260 ppb, was observed in maize.
Determination of Amino Acids in Food and Feed by Derivatization with 6-Aminoquinolyl-N-Hydroxysuccinimidyl Carbamate and Reversed-Phase Liquid Chromatographic Separation
Authors: Liu Hong Ji , Chang Bi Ying , Yan Hui Wen , Yu Feng Hua , Liu Xing Xiang
Published: February 2020

A study of a new amino acid analysis method using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as a precolumn derivatization reagent for the analysis of food and feed is described. All amino acids, including methionine sulfone and cysteic acid, were well separated on a liquid chromatographic system using the optimized chromatographic conditions. Salts in food and feed interfered very slightly with the derivatization yields of all amino acids. Several typical agricultural products and animal feeds, including 2 AOAC test samples, were analyzed with the method. The results agreed well with the data generated by using the classical postcolumn method with ion-exchange chromatography. The average relative standard deviations for corn and broiler starter feed were 0.74 and 0.70%, respectively. Good recoveries of all amino acids were demonstrated (average, 101%), even for a sample with a very complex matrix.
Supercritical Fluid Extraction of N-Nitrosamines in Hams Processed in Elastic Rubber Nettings
Authors: Pensabene John W , Fiddler Walter , Maxwell Robert J , Lightfield Alan R , Hampson James W
Published: February 2020

A method for analysing /V-nitrosamines in hams processed in elastic rubber nettings by supercritical fluid extraction (SFE) is described. The study was carried out with the prototype of a commercial extractor with a silica gel adsorption cartridge integrally attached to the variable restrictor. The SFE method was compared with a solid-phase extraction procedure currently used for ham analysis. Both methods used the same gas chromatographic–chemiluminescence detection conditions. No significant difference (p <0.05) was found between results obtained with the 2 methods. Repeatability standard deviation of the SFE method was 1.7 ppb, with a coefficient of variation (CV) of 2.7%, compared with 2.2 ppb, with a CV of 3.5%, for solid-phase extraction. SFE permits minimal use of solvent and more rapid analysis of nitrosamines.
Determination of Free and Total Carbohydrate Profile in Soluble Coffee
Authors: Prodolliet Jacques , Bruelhart Milene , Lador Fabienne , Martinez Cristtna , Obert Ladislav , Blanc Maurice B , Parchet Jean-Michel
Published: February 2020

A liquid chromatographic (LC) method was evaluated for the determination of free and total carbohydrates in soluble coffee. Samples are solubilized in water for free carbohydrates or hydrolyzed with LOON hydrochloric acid for total carbohydrates. An aliquot of the sample solution is analyzed on a pellicular anion-exchange polystyrene–divinylbenzene column using pure water as the mobile phase. Carbohydrates are quantitated by a pulsed amperometric detector. All major carbohydrates found in soluble coffee are determined in a single run. The technique allowed the detection of fraudulent addition of coffee husks or parchments as well as cereals or caramelized sugar for the 63 commercial products analyzed. High levels of free mannitol, free fructose, free glucose, sucrose, total glucose, and total xylose are a good indication of adulteration. Data were compared with those obtained from separate enzymatic determinations and from a different LC procedure. A close agreement among the methods was observed. However, the original method was superior in precision and was the only procedure that enabled the quantitation of all major carbohydrates. The technique is, therefore, a very powerful tool for routine analysis and for purity assessment of soluble coffee.
Enzyme Immunoassay for Carminic Acid in Foods
Authors: Yoshida Ayako , Takagaki Yutaka , Nishimune Takahiro
Published: February 2020

A competitive enzyme immunoassay (EIA) for carminic acid was investigated. Monoclonal anti-carminic acid antibody was obtained from A/J mice immunized with carminic acid-human immunoglobulin G (IgG) conjugate. Carminic acid was extracted with distilled water from beverage, jelly, candy, pasta sauce, yogurt, or ice cream samples. Ham or fish paste samples were digested with pro-nase, then carminic acid was extracted from samples with sodium hydroxide solution. The extract was diluted more than 10-fold with 1% gelatin in borate buffer solution. Microtiter plates were coated with carminic acid-bovine serum albumin (BSA) conjugate or just BSA. Goat anti-mouse lgG(H+L)-peroxidase complex was used as a second antibody, and 3,3′,5,5′-tetramethylbenzidine was used as a substrate for the peroxidase. The working range for quantitative analysis was 0.3–10 ng/mL, and the detection limit was 0.2 μg/g original sample. Recoveries of carminic acid by this assay were >95% for milk beverage and jelly, and >85% for yogurt and fish paste. Carminic acid was detected in 7 of 26 red-colored commercial food products and ranged from 3.5 to 356 μg/g. This EIA system also responded to the structural analogue of carminic acid, laccaic acid.
Determination of Hydramethylnon Residues in Grass by Liquid Chromatography with Confirmation by Liquid Chromatography/Mass Spectrometry
Authors: Stout Steven J , Peterson Robert P , Dacuhna Adrian R , Picard Gerald L
Published: February 2020

An improved method for determination of hydra-methylnon residues in pasture grass is described. The method uses (1) the hydrochloride salt of hy-dramethylnon to improve its water solubility and (2) an acid–methanol precipitation to remove chlorophylls while leaving the analyte in solution. The liquid chromatographic method has a validated sensitivity of 0.05 ppm with controls showing <0.004 ppm. The overall average recovery from 0.05 to 0.50 ppm was 98%, with a standard deviation of 11%. Samples showing a positive response (0.05 ppm or higher) and requiring mass spectrometric confirmation are directly amenable to liquid chromatography/mass spectrometry without additional sample preparation.
Extraction of Methamidophos Residues from Vegetables with Supercritical Fluid Carbon Dioxide
Authors: Valverde-García Antonio , Fernández-Alba Amadeo R , Agüera Ana , Contreras Mariano
Published: February 2020

A simple supercritical fluid extraction (SFE) method has been developed to efficiently extract incurred residues of methamidophos (a very polar pesticide) from fresh vegetable samples by using commercial SFE equipment and moderate SFE conditions. Vegetable samples were mixed with anhydrous magnesium sulfate and extracted with supercritical carbon dioxide at 300 atm and 50°C with methanol as static modifier and a few milliliters of ethyl acetate as trapping system. Methamidophos recoveries were >70% from 33 pepper, cucumber, and tomato samples at incurred levels ranging from 0.1 to 2.2 mg/kg. Triplicate analysis from 2 replicates at an incurred level of 0.53 mg/kg gave a coefficient of variation of 14%. Results for incurred residues of chlorpyrifos, endosulfan, and procymidone in some samples show that the SFE technique could be used as a multiresidue method.
Gas Chromatographic/Mass Spectrometric Analyses of Unknown Analytical Response in Imported Fava Beans: 4-Chloro-6-methoxyindole
Authors: Petzinger Glenn , Barry Thomas L , Roach John A G , Musser Steven M , Sphon James
Published: February 2020

A halogenated unidentified analytical response (UAR) was encountered in a number of imported Fava bean samples during the Food and Drug Administration’s routine pesticide-monitoring program. Gas chromatographic/mass spectrometric (GC/MS) analyses identified the halogenated component as 4-chloro-6-methoxyindole, a naturally occurring promutagen in Fava beans that has been linked to incidents of gastric cancer. Data from electron impact, positive and negative chemical ionization, collision-induced dissociation, and deuteration studies of this compound are presented, along with GC retention time data.
Survey of Lead, Cadmium, Fluoride, Nickel, and Cobalt in Food Composites and Estimation of Dietary Intakes of These Elements by Canadians in 1986–1988
Authors: Dabeka Robert W , Mckenzie Arthur D
Published: February 2020

During the period 1986–1988, foods were purchased at the retail level in 5 Canadian cities and, for each city, prepared for consumption and combined into 113 composites and 39 composite subsets. Lead and cadmium were determined in all the samples; fluoride, in samples from Winnipeg; and cobalt and nickel, in samples from Montreal. Means and ranges of concentrations (ng/g) found in individual samples were lead, 23.2 (<0.4–523); cadmium, 9.96 (<0.02–167); fluoride, 325 (11–4970); nickel, 196 (<0.6–2521); and cobalt, 9.4 (<0.3–75.7). Estimated dietary intakes (μg/day) of the elements over all ages and sexes were lead, 24; cadmium, 13; fluoride, 1763; nickel, 286; and cobalt, 11. During the period 1985–1988, the average level of lead in canned foods decreased from 73.6 to 46 ng/g.
Dietary Intakes of Pesticides, Selected Elements, and Other Chemicals: FDA Total Diet Study, June 1984–April 1986
Authors: Gunderson Ellis L
Published: February 2020

The U.S. Food and Drug Administration conducts the Total Diet Study to determine dietary intakes of selected pesticides, industrial chemicals, and elements (including radionuclides). The results reported here reflect the sampling period from June 1984 to April 1986. The study involves retail purchase of foods representative of the total diet of the U.S. population, preparation for table-ready consumption, and individual analyses of 234 items depicting the diets of 8 population groups. The diets were based on 2 nationwide food consumption surveys. The data presented represent 8 food collections (also termed “market baskets”) in regional metropolitan areas during the 2-year period. Dietary intakes of over 90 analytes are presented for the 8 population groups, which range from infants to elderly adults. Intakes of selected population groups are compared with representative previous findings. As reported previously, average daily intakes are well below acceptable limits.
Practical Screening Procedures for Sulfamethazine and N4-Acetylsulfamethazine in Milk at Low Parts-Per-Billion Levels
Authors: Schwartz Daniel P , Lightfteld Alan R
Published: February 2020

Relatively simple and inexpensive procedures for screening milk for sulfamethazine (SMZ) and one of its metabolites, N4-acetylsulfamethazine (ASMZ), are detailed. Both methods detect at the low partsper- billion level and are suitable for both field and laboratory use. Milk is passed over Chromosorb 102, which adsorbs SMZ. The drug is eluted and purified by direct passage of the effluent over small beds of buffered anion-exchange resins and alumina and is finally isolated and detected colorimetrically. For ASMZ, the procedure is modified so that SMZ is removed in the purification steps. The isolated ASMZ is then hydrolyzed to SMZ for detection. Application of the methods 5 years apart (1988 and 1993) shows that SMZ is still being used but to a lesser extent in 1993. Of over 250 samples screened in the 2 studies, only 2 were estimated to contain SMZ at 10 ppb, and the majority contained SMZ at 1 ppb. ASMZ was detected in a number of samples that were negative for SMZ.
Comparison of Modified Immunodiffusion and Bacteriological Analytical Manual (BAM) Methods for Detection of Salmonella in Raw Flesh and Highly Contaminated Food Types
Authors: Feldsine Philip T , Falbo-Nelson Maria T
Published: February 2020

A wide variety of naturally contaminated and inoculated raw flesh and highly contaminated food types was analyzed by a modified immunodiffusion enrichment protocol and the Bacteriological Analytical Manual (BAM) method to determine the equivalence of these methods. This modification was developed by Agriculture Canada to allow addition of a high-temperature selective enrichment step in tetrathionate brilliant green broth at 42°C while maintaining a 2-day total test time. Foods representing red meat, white meat, frog, and seafoods and one type of animal meal were evaluated. A total of 320 samples was tested, resulting in false negative rates of 5.2 and 3.5%, respectively, for the modified immunodiffusion and the BAM culture methods. The overall agreement rate was 96.9%.
Liquid Chromatographic Method for Determination of Dithianon in Technical Products and Formulations: Collaborative Study
Authors: Hanks Alan R
Published: February 2020

A liquid chromatographic method for determination of dithianon in technical products and formulations was evaluated by 22 laboratories participating in a collaborative study. Data received from 19 laboratories were used in the statistical analysis. The study included 3 technical grade materials, 1 suspension concentrate, and 1 wettable powder. Dithianon is determined by reversed-phase liquid chromatography on a C18 column with a mobile phase of acetonitrile and water. Detection at 254 nm with peak area measurements is used with an external standard for quantitation of dithianon. The liquid chromatographic method for determination of dithianon in technical products and formulations has been adopted first action by AOAC INTERNATIONAL.
Confirmation of Chloramphenicol Residues in Egg by Gas Chromatography/High-Resolution Mass Spectrometry and Comparison of Quantitation with Gas Chromatography–Electron Capture Detection
Authors: Börner Steffen , Fry Hildburg , Balizs Gabor , Kroker Reinhard
Published: February 2020

Determination of chloramphenicol (CAP) residues in egg by gas chromatography/high-resolution mass spectrometry (GC/HRMS) with negative chemical ionization and gas chromatography with electron capture detection (GC–ECD) is described. A cleanup based on acetonitrile extraction followed by solid-phase extraction with silica gel and gel filtration columns was developed for extraction of CAP residues from whole egg. For quantitation, the internal standards used were the meta isomer of CAP (m-CAP) for GC–ECD and both m-CAP and deuterium-labeled CAP (D5-CAP) for GC/HRMS. For GC/HRMS, evaluation was performed by selecting characteristic ions at m/z 466 for CAP and m-CAP and at m/z 471 for D5-CAP. Both methods were validated with egg samples fortified at 0.4–2.0 μg/kg and lyophilized egg samples from animals treated at the 1 μg/kg concentration level. The coefficient of variation was below 10%. Limits of detection and quantitation of both methods were about 0.3 and 0.5 ng/kg, respectively. For confirmation of CAP residues, the relative ion abundance (m/z 466 and 468) was calculated. Further confidence was obtained by comparison of accurate monoisotopic masses from a spectrum library.
Sugar, Nonvolatile Acid, 13C/12C Ratio, and Mineral Analysis for Determination of the Authenticity and Quality of Red Raspberry Juice Composition
Authors: Durst Robert W , Wrolstad Ronald E , Krueger Dana A
Published: February 2020

Analyses of sugars, nonvolatile acids, 13C/12C ratios, and minerals were conducted on 46 samples of red raspberry (Rubus idaeus) to develop a compositional database for evaluating authenticity and quality. Sample differences included cultivar (n = 10) and factors such as maturity, geographic origin, mold contamination, and harvesting procedures. A pilot-plant process typical of conventional commercial processing operations was used to process juices, along with newer technologies such as enzymatic liquefaction, diffusion extraction, and direct osmotic concentration. °Brix ranged from 7.0 to 15.0 with a mean of 9.95. All data have been normalized to 9.2 °Brix. Sorbitol expressed as percentage of total sugars ranged from 0 to 0.5% with a mean of 0.15%. Sucrose levels (range, 0–24.1%; mean, 1.4%) were highly variable. The glucoserfructose ratio ranged from 0.76 to 1.03 with a mean of 0.93. Citric acid is the major acid, ranging from 89.8 to 98.9% of total acids (mean, 95.6%; 1.70 g/100 mL). Malic acid ranged from 0.3 to 9.6% of total acids with a mean of 3.3% (66.1 mg/100 mL). Isocitric acid ranged from 0.2 to 2.6% (5.7–44.0 mg/100 mL) with mean of 1.1% (17.0 mg/100 mL). Potassium ranged from 108 to 400 mg/100 mL with a mean of 227.8 mg/100 mL. Sodium ranged from 0.2 to 4.0 mg/100 mL with a mean of 2.1 mg/100 mL. Magnesium ranged from 11.3 to 29.4 mg/100 mL with a mean of 18.6 mg/100 mL. Calcium ranged from 8.0 to 16.3 mg/100 mL with a mean of 12.5 mg/100 mL. 13C/12C ratios ranged from –26.0 to –21.9‰ PDB (PeeDee Belemnite) with a mean of –24.2‰.
Modified Acid Phosphatase Assay for Assessing the Extent of Heating of Canned Picnics and Hams: Interlaboratory Study
Authors: Körmendy L , Zsarnóczay Gabriella , Cattaneo Patrizia , Cantoni C , Consiglteri C , Casagrande G , Savio G , Wenzel S , Kühne M , Bálint Georgtna , Pactheco Ertka , Gaugecz Janka , Gimesi Andrea , Herman Andrea , Fekete Z , Juhász S , Szentgyörgyi Maria , Major-Földi Kamtlla , Szabó A S , Simon Anna , Farkas J
Published: February 2020

Determination of acid phosphatase (E.C. 3.1.3.2.) activity in meat and meat products Is based on spectrophotometric measurement of free phenol released from phenyl phosphate substrate during enzyme catalysis under prescribed conditions. Precision parameters of a new modified phosphatase assay, proposed for determination of extent of heating of canned picnics and hams, were evaluated in an interlaboratory study with 10 (1 German, 2 Italian, and 7 Hungarian) participating laboratories. The test materials were 5 lean meat batters subjected to different heat treatments (i.e., with different levels of phosphatase activity). The materials were presented to participants as 10 randomly coded samples (2 blind replicates of each material). The interlaboratory study was then repeated with 3 test materials and 2 blind replicates (3 × 2) prepared in the same way. The repeatability relative standard deviation (RSDr), outliers excluded, varied from 2.2 to 10.7%, and the reproducibility relative standard deviation (RSDR) varied from 12.6 to 25.3%. Results were compared with other data in the literature. The sensitivity of the new modified phosphatase assay was also compared with that of the original procedure described in USDA Chemistry Laboratory Guidebook. A higher sensitivity was observed for the method described in this paper. However, the method’s reproducibility was poorer than that of common analytical methods. Although high, the variability may still be acceptable for determining phosphatase activity to assess extent of heat treatment of canned picnics and hams.
Sample Preparation for Volatile Oil Analysis of Cassia Bark
Authors: Zapf Charles M , Parrish Mark
Published: February 2020

We established that the choice of the laboratory mill has little effect on steam-distillable volatile oil (VOSD) analysis of Cassia bark when reasonable care is used in preparing single samples. When multiple samples are milled, caution is advised to avoid temperature increase. Data from 11 laboratories are presented for 4 test samples. Participating laboratories milled 200 g samples, and the variation of the resulting VOSD in the ground spice could not be attributed to the different grind-size profiles measured. The estimated systematic error due to type of mill was 0.04 mL/100 g. This represents a relative standard deviation of 2.2% for the lowest average volatile oil levels.
Capillary Gas Chromatography–Atomic Emission Detection Method for the Determination of Pentylated Organotin Compounds: Interlaboratory Study
Authors: Liu Yan , Lopez-Avila Viorica , Alcaraz Marcela , Beckert Werner F
Published: February 2020

A capillary gas chromatography-atomic emission detection (GC–AED) method was developed for the U.S. Environmental Protection Agency’s Environmental Monitoring Systems Laboratory in Las Vegas, NV, for determination of selected organotin compounds. Here we report on an interlaboratory study to establish whether these compounds can reliably be detected and quantitated by this method and to establish the interlaboratory precision and accuracy with currently available instrumentation. A blind, balanced-replicate design was selected for this study, based on a recommendation of AOAC INTERNATIONAL. Ten laboratories volunteered for this study. Each laboratory received 5 calibration standards (pentylated organotin compounds), 3 pentylated soil or sediment extracts (prepared in our laboratory by an in situ complexation/supercritical fluid extraction method), and 1 pentylation blank. The participating laboratories analyzed the extracts according to our instructions and submitted the data to us for statistical analysis. Of 720 individual sample results, the number of outliers identified with the Cochran test was 60 (8.3%). Two laboratories accounted for most of the outliers. Results indicate that good chromatographic performance was achieved regardless of the type of injection inlet; however, electronic pressure control was needed to achieve acceptable chromatography for tetracyclohexyltin and tetraphenyltin. The intralaboratory precisions of the GC-AED method ranged from 1.3 to 22% relative standard deviation (RSD), depending on the compound. The interlaboratory method precisions ranged from 11 to 40% RSD over the concentration range tested.
Recovery of Salmonella spp. from Refrigerated Preenrichment Cultures of Dry Food Composites
Authors: D’Aoust Jean-Yves , Sewell Anne M , McDonald Cathy
Published: February 2020

Refrigerated preenrichment 72 h and selective enrichment cultures arising from 25 g analytical units of dry foods can be used to increase the analytical flexibility and productivity of laboratories for the detection of food borne Salmonella spp. by AOAC method 994.04. Results of this intraiaboratory study using artificially jcontaminated dry foods validate the extended application of the refrigerated preenrichment approach to dry food composites (375 g). All samples found to be contaminated by AOAC/Bacteriological Analytical Manual methods were identified readily from the homologous, refrigerated preenrichment broth cultures. This extended application of the refrigeration approach was recently adopted First Action by AOAC and was included as a modification to method 994.04. In addition, ancillary work on the diagnostic value of prolonged (48 h) incubation of lysine iron (LI) agar as described in the AOAC Official Method 967.26 led to a recommendation that the 48 h period of incubation be revoked in favor of a 24 h incubation of inoculated LI medium.
Automated Sample Preparation for Monitoring Groundwater Pollution by Carbamate Insecticides and Their Transformation Products
Authors: Chiron Serge , Valverde Antonio , Fernandez-Alba Amadeo , Barceló Damiá
Published: February 2020

We investigated automated on-line solid-phase extraction (SPE) followed by liquid chromatographic (LC) techniques for monitoring carbamates and triazines and their transformation products. Analytical determinations were performed by LC with UV or postcolumn fluorescence detection (U.S. Environmental Protection Agency Method 531.1 for carbamate insecticides) after preconcentration with on-line SPE using C18 Empore extraction disks. Online SPE/LC/thermospray mass spectrometry with time-scheduled selected-ion monitoring was used as confirmatory method. The method was used to determine pesticide traces in well waters of a typical aquifer in the Almeria area (Andalucia, south of Spain) from March 1993 to February 1994. The major pollutants, found in highest amounts, were carbofuran, methiocarb, and methomyl, at levels of 0.32,0.3, and 0.8 μg/L, respectively. According to results of seasonal variation studies, pollution by carbamate insecticides is sporadic and exceeds the limit of 0.5 μg/L for total pesticides allowed by the European Economic Community Drinking Water Directive only twice a year. 3-Hydroxycarbofuran and methiocarb sulfone also were detected, showing the importance of including the main toxic breakdown products of carbamate insecticides in future monitoring programs.
FDA Total Diet Study, July 1986-April 1991, Dietary Intakes of Pesticides, Selected Elements, and Other Chemicals
Authors: Ellis L. Gunderson
Published: February 2020

The U.S. Food and Drug Administration conducts the Total Diet Study to determine dietary intakes of selected pesticides, industrial chemicals, and elements (including radionuclides). This paper reports results for the sampling period July 1986 to April 1991. The study involves retail purchase of foods representative of the "total diet" of the U.S. population, preparation for "table-ready" consumption, and individual analyses of 234 items making up the diets of 8 population groups. The diets were based on 2 nationwide food consumption surveys. The data presented represent 21 food collections (also termed "market baskets") in regional metropolitan areas during the 5-year period. Dietary intakes of nearly 120 analytes are presented for 8 population groups, which range from infants to elderly adults. Intakes of selected population groups are compared with representative findings from earlier Total Diet Study sampling periods. As reported previously, average daily intakes are well below acceptable limits.
Atomic Emission Detection for Gas Chromatograpic Analysis of Nitrogen-Containing Herbicides in Water
Authors: Olson Norman L , Carrell Robert , Cummings Randal , Rieck Robert , Reimer Steven
Published: February 2020

A gas chromatography-atomic emission detection (GC–AED) system was used to analyze nitrogencontaining herbicides. Two methods of sample preparation were used to demonstrate the system’s applicability. Method 1 was U.S. Environmental Protection Agency (EPA) Method 507. Method 2 was a modification of EPA Method 507 using larger sample volumes and smaller extract volumes to yield compound detection levels 30 times lower than detection levels from method 1. Analysis of replicate reagent water spikes with method 1 gave analyte recoveries ranging from 82 to 107%, with standard deviations of recovery of not more than 6.7%. Method 2 gave recoveries ranging from 50 to 112%, with a standard deviation of recovery of not more than 33%. A loss in recovery and precision with method 2 compared with method 1 was attributed to loss of more volatile analytes during extract concentration. Selectivity was demonstrated with solvent spiked with fuel oil and atrazine. Response factors generated with the GC–AED system showed compound-independent elemental linearity for analytes. Relative standard deviations of not more than 5.34% were obtained for 3 elements tested: nitrogen, sulfur, and chlorine. An elemental calibration mixture was prepared to validate traditional methods of quantitation. Samples were analyzed for nitrogen-containing herbicides, which were quantitated with both an analyte calibration and an elemental calibration, and results were compared.
Application of Triphenyltetrazolium Chloride in Microbial Limit Test of Pharmaceuticals and Cosmetics
Authors: Ohara Mjtsuko Taba , Saito Takako
Published: February 2020

An alternative method was developed for counting viable microbial contaminants in pharmaceuticals and cosmetics with insoluble materials and low bioburden. The method uses triphenyltetrazolium chloride (TTC). The inhibitory effect of TTC on microbial growth observed by others was eliminated by adding it as an overlay, after incubation of sample in culture medium for 48 h. Six samples of pharmaceutical suspensions and 6 samples of cosmetics were evaluated by most-probable number (MPN) and pour-plate techniques with TTC in comparison with MPN with subculturing. The equivalence between MPN technique with TTC and subculturing was demonstrated for all samples and between pour-plate and subculturing for 10 samples. The differences were probably due to some error inherent to both techniques and not from application of TTC. Comparison of coefficients of variation showed that plate countings were more precise than the MPN method, as expected.
History of the Food and Drug Administration’s Total Diet Study (Part II), 1987-1993
Authors: Pennington Jean A T , Capar Stephen G , Parfitt Charles H , Edwards Curtis W
Published: February 2020

The Total Diet Studies conducted by the U.S. Food and Drug Administration (FDA) provide yearly information on levels of pesticide residues, contaminants, and nutrients in the food supply and diets of specific age-sex groups. They also identify trends and changes in the levels of thesesubstances in the food supply and in diets over time. Results are useful in making policy decisions regarding the safety of the food supply, food additives, pesticide use, nutrient fortification, and food labeling. This paper provides information on studies performed by FDA from 1987 to1993.
Iron Determination in Fertilizers by Inductively Coupled Plasma Atomic Emission Spectrometry: Study of Spectral and Interelement Effects at Different Wavelengths
Authors: Matilainen Rose , Tummavuori Jouni
Published: February 2020

Four analytical wavelengths of iron (238.204, 239.562, 259.940, and 240.488 nm) were tested for determination of Fe in fertilizers by inductively cou pled plasma atomic emission spectroscopy (ICP AES). Variations in measurements were caused by the changing interference pattern at different wave lengths evaluated by multiple linear regression. Thus, results obtained with different wavelengths are not comparable. Ca, P, and K were typical ele ments causing interference in almost all examined Fe wavelengths. Wavelength Fe II 238.204 nm is the best wavelength for determination of Fe in fertiliz ers by ICP-AES. Method accuracy is ± 8% at the ex amined Fe levels in fertilizers.
Determination of Chlorobiphenyls in Seal Blubber, Marine Sediment, and Fish: Interlaboratory Study
Authors: Boer Jacob De , Meer Jaap Van Der , Brinkman Udo A Th
Published: February 2020

Between 1988 and 1994, the International Councilfor the Exploration of the Sea, the Intergovernmental Oceanographic Commission, and the Oslo and Paris Commissions organized a stepwise interlaboratory study for determination of chlorobiphenyls (CBs) inmarine media. The final parts of this study, in which 53 laboratories from 14 countries participated, focused on long-term precision, cleanup, and extraction. Calibration was controlled continuously by analysis of 10 CBs in an unknownsolution. Participants were requested toanalyze 3 CBs in a certified reference material fish oil (6 times); 10 CBs in cleaned and uncleaned marine sediment and seal blubber extracts; and 10 CBs in seal blubber oil, dried marine sediment, and wet, lean fish muscle tissue. The long-term precision study showed that, compared with earlier exercises in which only duplicate analyses were required, repeatability increased about 1.5-fold compared with reproducibility. The mean standard error for reproducibility of determination of 10 CBs in standard solutions improved from 1.22 to 1.15. The standard error improved from 1.36 to 1.28(without CBs 28 and 31) for seal blubberoil and from 1.36 to 1.22 for dried marine sediment. In seal blubber oil and dried marine sediment, the major CBs 118,138,153, and 180 can now bedetermined by thegroup of participating laboratories with a reproducibility of 1.5 (about 50%). No significant differences were found between results for cleaned-up and un cleaned extracts. No acceptable results could be obtained for determination ofCBs in lean fish muscle tissue. Biplots of principal component analyses are extremely helpful in evaluating the data generated by this type of study.
Determination of Tetracyclines in Animal Feeds in the Presence of Other Drugs by Thin-Layer Chromatography and Microbiological Method
Authors: Markakis Pantelis K
Published: February 2020

This method was developed to separate, detect, and quantitate oxytetracycline (OTC) or chlortetracycline hydrochloride (CTC HCI) in animal feeds in thepresence of 11 otherdrugs: 3 nitrofurans, 2 macrolideantibiotics,3 sulfonamides, 2 coccidiostatics, and 1 antibacterial growth promoter. OTC or CTC HCI was separated from coexisting drugs and detected by thin-layer chromatography, then quantitated microbiologically by the agar diffusion method. Analysis of 125 experimental animal feed samples fortified at 5 levels (7.5-400 ppm) with OTC or CTC HCI and at 1 level (50 ppm) with the rest of the drugs, respectively, gave a limit of quantitation of 1.25 or 0.625 ppm, a recovery of 90.6 or 92.9%, and a coefficient of variation of 2.9-6.1 or 2.3-4.4%.
Multiresidue Method for Confirmation of Macrolide Antibiotics in Bovine Muscle by Liquid Chromatography/Mass Spectrometry
Authors: DelÉpine Bernard , Hurtaud-Pessel Dominique , Sanders Pascal
Published: February 2020

A particle beam/liquid chromatographic/mass spectrometric (PB/LC/MS) method capable of determining 5 macrolides in bovine muscle is described. Spiramycin, tylosin, tilmicosin, erythromycin, and josamycin residues in bovine muscle are confirmed by reversed-phase LC/MS incorporating gradient elution. Macrolides are extracted from tissue with chloroform, and the extract is purified with a diol solid-phase extraction cleanup. The 5 macrolides are identified by negative and positive chemical ionization with selective ion monitoring of 2 ions in each mode. The procedure confirms the presence of each macrolide at 50 μg/kg in spiked samples.