bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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 &gt;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

Abstract
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

Abstract
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 (&lt;0.4–523); cadmium, 9.96 (&lt;0.02–167); fluoride, 325 (11–4970); nickel, 196 (&lt;0.6–2521); and cobalt, 9.4 (&lt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.