bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Resolution Gas Chromatography of Chlorinated Benzenes
Authors: Miller Lee J , Farrell Terryl J , Puma Bart J 
Published: February 2020

Abstract
Chlorinated benzenes have been found as contaminants in foods and water. These high production volume chemicals may enter the environment and food chain through improper waste disposal, use as solvents and odor control agents, or as impurities in other industrial chemicals. Because of differences in the electron capture responses of the isomers at each chlorination level, residue quantitation requires the separation of all 12 chlorobenzenes. Resolution studies were made on packed and capillary columns coated with Kovats’ C87H176 hydrocarbon, OV-101, OV-210, OV-17, and Carbowax 20M. Satisfactory resolution of all 12 chlorobenzenes was obtained with a Carbowax 20M-coated 20 m × 0.25 mm id capillary column operated isothermally at 120°C.
Portable Micro Method for Quantitative Determination of Vitamin C in Fruit and Vegetable Juices
Authors: Rymal Kenneth S 
Published: February 2020

Abstract
A portable rapid and accurate micro method is described for the quantitative determination of vitamin C in fruit and vegetable juices. Chromatographic paper is impregnated with DCP by immersion in 95% ethanol solution and sprayed with a protective starch solution. Papers are usable indefinitely when protected from moisture, light, air, and high temperatures. Determinations can be completed in 60 s with an accuracy of ±2.0 mg/100 mL fruit or vegetable juice. Cloudy or lightly colored samples do not interfere with the determination. The method was compared with the official AOAC 2,6-dichloroindophenol (DCP) titration method and gave a linear correlation coefficient of 0.99749.
Simple, Sensitive Technique for Detection and Separation of Halogenated Synthetic Pyrethroids by Thin Layer Chromatography
Authors: Sundararajan Radhakrishnan , Chawla Ram Parkash 
Published: February 2020

Abstract
Thin layer chromatography employing silver nitrate-impregnated alumina G plates has been extended for the routine detection and confirmation of the identity of halogenated synthetic pyrethroid insecticides. Of the solvent systems tried, maximum resolution was achieved by using n-hexane-benzene (45+ 55) and n-hexane-chloroform (60 + 40), which gave distinct separations of the cis- and trans-isomers of permethrin and cypermethrin from fenvalerate and decamethrin. Possible interference of HCH isomers and DDT and its analogs can also be checked by a concurrent run of the sample mixture in these 2 systems. A minimum of 50 ng each of cis- and trans-permethrin and cypermethrin isomers and fenvalerate and decamethrin can be positively detected. Using this technique, the minimum detectable limit of permethrin was 0.1 ppm in the cleaned up extracts of tomato plant and fruit and soil samples.
pplicability of a Multiresidue Method and High Performance Liquid Chromatography for Determining Quinomethionate in Apples and Oranges
Authors: Krause Richard T , August E Michael 
Published: February 2020

Abstract
The AOAC multiresidue method for nonpolar pesticide residues in nonfatty foods has been coupled with a high performance liquid chromatographic (HPLC)-fluorometric system for determining quinomethionate residues on apples and oranges. Quinomethionate is extracted with acetonitrile, and coextractives are removed with liquid-liquid partitioning and Florisil adsorbent using the AOAC multipesticide residue method for nonfatty foods. The quinomethionate fraction is then chromatographed on an HPLC octyl-bonded column and detected in-line with a fluorescence detector using 362 nm excitation and 395 nm emission. Recovery studies were conducted with apples fortified with quinomethionate at 0.05 ppm and oranges at 0.05 and 0.5 ppm. The recoveries averaged 100% (range 92-108) at the 0.05 ppm fortification level and 102% (range 93-110) at the 0.5 ppm level.
Analysis of Pesticide Residues by Chemical Derivatization. VI. Analysis of Ten Acid Herbicides in Sediment1
Authors: Lee Hing-Biu , Chau Alfred S Y 
Published: February 2020

Abstract
A sensitive gas-liquid chromatographic (GLC) method was developed for multiresidue analysis of 10 acid herbicides in sediment. An acidified sediment sample was extracted 3 times with acetonehexane. The combined organic extract was partitioned with acidified water to remove aqueous coextractives. To produce low detection limits for all herbicides including MCPA and MCPB for routine monitoring purposes, pentaf luorobenzyl esters were formed before GLC analysis. Recoveries of all herbicides from fortified sediment samples were better than 80% at the levels studied. Practical detection limits of this method were 10-25 μg/kg (ppb).
Mojonnier Method as Reference for Infrared Determination of Fat in Meat Products
Authors: MILLS Bernice L , Voort F R Van De , Usborne W R 
Published: February 2020

Abstract
The Mojonnier method was compared with the conventional Soxhlet method for the determination of fat in 7 different meat products to assess its use as a standard reference method for calibration of commercial quantitative infrared transmission analyzers (e.g., Multispec M, Milkoscan 300 or 104). Results for the meat samples obtained by the Mojonnier method did not differ significantly from those obtained by the Soxhlet method. In addition, the Mojonnier method was less time-consuming and more precise than the Soxhlet; therefore, it can be used as a standard reference procedure for the calibration and assessment of infrared milk analyzers in their potential application to the rapid determination of fat in meat and meat products.
Gas-Liquid Chromatographic Determination of Sucrose Fatty Acid Esters
Authors: Tsuda Taizo , Nakanishi Hiroshi 
Published: February 2020

Abstract
A method was developed for gas-liquid chromatographic determination of sucrose fatty acid esters as TMS derivative of sucrose and methyl esters of fatty acids. Sucrose fatty acid esters were completely degraded to sucrose and fatty acids in alkaline ethanol overnight at 25°C. Sucrose was derivatized with pyridine, trimethylchlorosilane, and N-trimethylsilylimidazole and the sucrose TMS derivative was determined on a 2% OV-17 column. Fatty acids were extracted with ethyl ether, methylated with BF3-methanol complex at 65°C, and determined on a 2% DEGS + 0.5% H3PO4 column. This method was applied to selected sucrose fatty acid esters. For example, sucrose and fatty acids derived from 50 mg sample F20 were 10.6-11.0 and 38.1-39.0 mg, respectively. Total amounts were 48.7-50.0 mg with a standard deviation of 0.4 (n = 6).
Rapid High Pressure Liquid Chromatographic Determination of Anatoxin M1 in Milk and Nonfat Dry Milk
Authors: Chang Henry L , DeVries Jonathan W 
Published: February 2020

Abstract
A modification of the current revised AOAC method, 26.A10-26.A15, is described for the rapid analysis of aflatoxin Mi in milk and nonfat dry milk. The method incorporates chloroform extraction and eliminates the need for column chromatography by using liquid-liquid partition for sample extract cleanup. Quantitation is carried out by using fluorescence detection combined with high pressure liquid chromatography (HPLC) of aflatoxin M1 which has been converted to aflatoxin M2a with trifluoroacetic acid. The method has a detection limit of 0.014μg/L (2 X signal/noise) for whole milk. For 6 samples of naturally contaminated nonfat dry and fteeze-dried milk, the modified method gave an average result of 0.698 μg/L; the AOAC method gave an average result of 0.386 μg/L.
Nonaqueous Reverse Phase Liquid Chromatographic Determination of Vitamin D2 in Multivitamin Tablets, Using Vitamin D3 as Internal Standard
Authors: Fong Godwin W K , Johnson Raymond N , Kho Boen T 
Published: February 2020

Abstract
The technique of nonaqueous reverse phase chromatography has been successfully applied to the separation of lipophilic vitamins D2 and D3. Separation is achieved with a Zorbax-ODS column and a mobile phase of 10% methanol in acetonitrile. A predetermined amount of vitamin D3 internal standard is added to a portion of a powdered tablet sample, which is then extracted and partitioned with a mixture of dimethyl sulfoxide, water, methanol, and hexane. A portion of the hexane extract is concentrated, and purified by passing it through a disposable silica cartridge to remove interfering materials. The method should also be applicable to formulations containing vitamin D3 where vitamin D2 can then be used as the internal standard. A system suitability test is included in the method.
Evaluation of Potential Analytical Approach for Determination of Polychlorinated Biphenyls in Serum: Interlaboratory Study
Authors: Burse Virlyn W , Needham Larry L , Lapeza Chester R , Korver Margaret P , Liddle John A , Bayse David D 
Published: February 2020

Abstract
Forty-four laboratories participated in evaluation of a method for determining polychlorinated biphenyls (PCBs) as AR 1254 in serum at the parts per billion level. The method involves deproteinating serum with methanol, extracting with hexane-ethyl ether, and eluting PCBs from deactivated silica gel for gasliquid chromatographic determination with electron capture detection. Compounds are quantitated by using the Webb-McCall factors. Five serum pools, 4 containing in vivo-fortified PCBs (as AR 1254) or 8 in vitro-f ortif ied chlorinated hydrocarbons (CHs), or both, were used. For PCB fortification levels of 9.89 (EP 2), 24.74 (EP 3), and 74.20 ppb (EP 4), interlaboratory coefficients of variation (CVs) for collaborators that adhered to protocol were 92.7, 67.6, and 25.8%, respectively. CVs on the same pools analyzed by the Centers for Disease Control (CDC) were 7.4, 7.8, and 4.6%, respectively. Average interlaboratory recoveries for pools EP 2, EP 3, and EP 4 were 138.1,111.2, and 91.1%, respectively, and 99.8,89.6, and 90.4%, respectively, for CDC on the same pools. There was a general decrease in the mean error for those laboratories that had participated in an earlier study in which they were allowed to use their own methods.
Determination of Acrylonitrile in Foods by Headspace Gas-Liquid Chromatography with Nitrogen-Phosphorus Detection
Authors: Page B Denis , Charbonneau Claudette F 
Published: February 2020

Abstract
A general procedure is described for the determination of acrylonitrile (AN) in foods such as margarine, honey butter, cold-pack cheese, and peanut butter, which are likely to be packaged in AN-based plastic. The entire sample is blended with water and salt at &lt;5°C, aliquots are sealed in crimp-top vials, and the vials are equilibrated in a boiling water bath. The headspace is sampled by using a heated syringe, and AN is determined by gas chromatography with a nitrogen- phosphorus selective detector. The inclusion of propionitrile as an internal standard allows quantitation of AN with detection at 4,4, and 10 ppb for margarine, honey butter, and cold-pack cheese, respectively. A peak corresponding to about 5 ppb apparent AN in all non-AN-packaged peanut butter samples examined limits detection in peanut butter to about 15 ppb. The coefficients of variation at 20 ppb for margarine, honey butter, cold-pack cheese, and peanut butter were 7.5, 8.3, 7.3, and 10.2%, respectively.
Filament Hygrometer for Water Activity Measurement: Interlaboratory Evaluation
Authors: Jakobsen Mogens 
Published: February 2020

Abstract
A method is presented for measuring water activity (aw) of foods with a filament hygrometer. An interlaboratory evaluation carried out for the Nordic Committee on Food Analysis demonstrated that measurements can be made with a repeatability and reproducibility of 0.005 and 0.010 aw, respectively. The critical parameters of aw measurements are defined and discussed in relation to the accuracy and reproducibility required. The need for strictly standardized procedures for maintenance of the equipment, sample treatment, calibration, and measuring is emphasized.
Comparison of Iron Milk and Official AOAC Methods for Enumeration of Clostridium perfringens from Fresh Seafoods
Authors: Abeyta Carlos 
Published: February 2020

Abstract
Fresh seafoods collected from Seattle area markets were evaluated for the presence and numbers of Clostridium perfringens. In a comparison of the official AOAC Shahidi-Ferguson perfringens and the simple iron milk methods, 29 of 287 samples of fresh fish and shellfish were positive for C. perfringens. All 29 positive samples were detected by the iron milk medium; however, only 7 of the 29 were detected by the AOAC methods. A statistical evaluation of the data showed a significant difference between the 2 methods
Liquid Chromatography of Liquid Formulations Containing 2,4-Dichlorophenoxyacetic Acid, Dicamba, and 2-(2-Methyl-4-chlorophenoxy)propionic Acid as Their Salts
Authors: Grorud Robert B , Forrette John E 
Published: February 2020

Abstract
A high pressure liquid chromatographic method has been developed for liquid herbicide combinations that contain different combinations of 3 active ingredients including 2,4-dichlorophenoxyacetic acid (2,4-D), 2-(2-methyl-4-chlorophenoxy)propionic acid (MCPP), and dicamba. A reverse phase column in the ion suppression mode and a binary solvent system separate all 3 herbicides quantitatively on a single chromatogram. The internal standard solution may contain 2 internal standards, salicylic acid and butyrophenone, for use with certain combinations of the herbicides. The solvent system resolves the compounds of interest from all significant impurities.
Composition of Apple Juice
Authors: Mattick Leonard R , Moyer James C 
Published: February 2020

Abstract
Thirty-one samples from 8 geographic growing regions of the United States and 15 varieties common to these areas were converted to apple juice and analyzed for their attributes over the 3 year period 1979, 1980, and 1981. The total of 93 samples were analyzed for ash, brix, pH, proline, specific gravity, total acid, sorbitol, sucrose, fructose, and glucose. The elements cadmium, calcium, iron, lead, phosphorus, potassium, sodium, and zinc were also determined. These data are presented to serve as a data base for the detection of fraudulent or adulterated apple juice.
Gas Chromatographic Determination of Maleic Hydrazide Residues in Potato Tubers
Authors: King Russell R 
Published: February 2020

Abstract
A gas chromatographic (GC) method is described for the determination of maleic hydrazide residues in potato tubers by oxidation of maleic hydrazide with aqueous lead dioxide to 3,6-pyridazinedione in the presence of cyclopentadiene. The reaction product, i volatile Diels-Alder adduct, could be detected in potatoes at levels in excess of 0.05 ppm with an electron capture detector. Recoveries of maleic hydrazide (as the Diels-Alder adduct) from potatoes at fortification levels of 0.1 to 10 ppm averaged 91.7%.
Interlaboratory Study of the Hall 700A Halogen Electrolytic Conductivity Gas Chromatographic Detector
Authors: Carson Louis J 
Published: February 2020

Abstract
An interlaboratory study of the Hall 700A (halogen) electrolytic conductivity GC detector was carried out in 8 Food and Drug Administration laboratories. The study sought to provide data to support the use of the Hall 700A (halogen) detector as an alternative to the electron capture and microcoulometer detectors in the determination of pesticide and industrial chemical residues. The following characteristics of the detector were studied: linear dynamic range for 12 organohalogen pesticides and industrial chemicals injected over a 0.05-27.00 μg/mL range; repeatability of response; quantitation of 5 pesticides and Aroclor 1254 added to food extracts (fish and green peppers) cleaned up by commonly used multiresidue analytical methods; selectivity, defined as response to a halogenated compound (chlorpyrifos) vs response to a nonhalogenated compound (caffeine). The interlaboratory study showed that halogen response and selectivity are independent factors which define the performance of the Hall 700A (halogen) detector. Recommendations are provided to ensure consistent and selective halogen response. Finally, the study provides adequate data to support continued use of the Hall 700A (halogen) detector in the determination, of pesticides and industrial chemicals.
Determination of Coumaphos and Its Oxygen Analog in Eggs and Milk by Using a Multiresidue Method with Liquid Chromatographic Quantitation and Capillary Gas Chromatographic/Mass Spectrometric Confirmation
Authors: Krause Richard T , Min Zhao , Shotkin Sharona H 
Published: February 2020

Abstract
A multiresidue method for carbamate insecticides was adapted for the determination of coumaphos and its oxygen analog in eggs and milk. Eggs were extracted with acetonitrile and milk was extracted with acetone. Co-extractives were removed using liquid partitioning and charcoal column procedures described in the carbamate method. Coumaphos and its oxygen analog were determined by using a high performance liquid chromatograph equipped with a fluorescence detector. Recovery studies were performed for the 2 compounds at levels of 0.01 and 0.10 ppm in eggs and 0.01 and 0.02 ppm in milk. Overall average recovery was 100% (range 95-109%). In a trial of the method by another laboratory, the recovery of coumaphos and its oxygen analog from milk averaged 87 and 96%, respectively. Data are presented on the capillary gas chromatographic/mass spectrometric confirmation of coumaphos residues.
Simultaneous Spectrophotometric Determination of Amodiaquine-Primaquine Mixtures in Dosage Forms
Authors: Hassan Sayed M , Metwally Mohammed E-S , Malek A Abdel 
Published: February 2020

Abstract
Using 0.1N hydrochloric acid as solvent, mixtures of amodiaquine and primaquine have been measured at 282 and 342 nm. The concentration of each can then be calculated by solving 2 simultaneous equations. Excellent recoveries from authentic samples were obtained and the method proved suitable for routine analysis.
Rapid Detection of Fusarium Mycotoxins in Grains by Quadrupole Mass Spectrometry/Mass Spectrometry
Authors: Plattner Ronald D , Bennett Glenn A 
Published: February 2020

Abstract
The Fusarium mycotoxins deoxynivalenol (DON) and zearalenone can be detected rapidly in a crude extract of a grain matrix by quadrupole mass spectrometry/ mass spectrometric analysis of the collisionally activated dissociation (CAD) daughter fragments of the protonated molecule. Detection limits were as low as 0.1 ppm. The 2 toxins were detected in a single analysis. Monitoring the CATJ daughters of the negative ion m/z 248 of DON eliminated most interferences from the grain matrix and produced daughter spectra identical to those produced from an authentic standard.
Gas Chromatographic Determination of Deoxynivalenol in Wheat
Authors: Bennett Glenn A , Stubblefield Robert D , Shannon Gail M , Shotwell Odette L 
Published: February 2020

Abstract
Modifications to a published method are described for the determination of deoxynivalenol (DON) in wheat by gas chromatography with electron capture quantitation of the heptafluorobutyrate derivative. In the modified method, DON is extracted by shaking the sample with methanol-water on a wrist-action shaker, followed by filtration through rapid flow paper. One concentration step is eliminated, and a hexane wash is incorporated to remove toluene from the silica gel column. Recoveries of DON from wheat samples spiked at 0.1,0.5, and 1.0 ppm ranged from 77.3 to 86.3% and averaged 81.5%.
Survey of Baby Bottle Rubber Nipples for Volatile N-Nitrosamines
Authors: Havery Donald C , Fazio Thomas 
Published: February 2020

Abstract
A local market survey of 27 baby bottle rubber nipples for volatile N-nitrosamines was conducted. N-Nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine, and N-nitrosopiperidine were found at levels up to 387 ppb. All 4 nitrosamines migrated from the rubber nipples into water, milk, and infant formula when sterilized together in a manner typical of that used in the home. The source of the nitrosamines is the chemical accelerators and stabilizers added to raw rubber during the vulcanization process.
Improved Cleanup and Derivatization for Gas Chromatographic Determination of Monosodium Glutamate in Foods
Authors: Nakanishi Hiroshi 
Published: February 2020

Abstract
A gas chromatographic procedure is described for determining monosodium glutamate (MSG) in several types of food. A sample is extracted with acetone- water (1 + 1). Acetone is evaporated and an aliquot of the extract is buffered with 1M NH4OH-1M NH4CI pH 9 solution, and chromatographed directly on a column of QAE Sephadex A-25 that has been pretreated with the same buffer. MSG is eluted with 0.1N HC1, and a portion of the eluate is evaporated to dryness and reacted with dimethylformamide( DMF)-dimethylacetal to form the glutamic acid derivative, which is injected into a gas chromatograph and measured by flame ionization detection. Recoveries of MSG from sample fortified at 5-500 mg ranged from 92.8 to 100%.
Pesticide Residue Levels in Foods in the United States from July 1,1969, to June 30,1976: Summary
Authors: Duggan Reo E , Corneliussen Paul E , Duggan Mary B , Mcmahon Bernadette M , Martin Robert J 
Published: February 2020

Abstract
The U.S. food supply was examined for pesticide residues during the 7-year period covering Fiscal Years (FY) 1970 through 1976. The results, which are contained in the report summarized here, are a continuation of an earlier report for the 6-year period FY 1964-1969.
Validated Extraction and Cleanup Procedures for Polychlorinated Biphenyls and DDE in Human Body Fluids and Infant Formula
Authors: Mckinney Lois Moore James D , Prokopetz Andrew , Walters Douglas B 
Published: February 2020

Abstract
As part of an epidemiology study, extraction methods and extract cleanup procedures were developed and validated for polychlorinated biphenyls (PCBs) and DDE, an ubiquitous metabolite of DDT, in human milk, blood serum, and infant formula. Studies included quantitative and reproducible recovery of total lipids, and reproducible and reasonably high recoveries of these chlorinated compounds from the human body fluids and infant formula, including levels of environmental health interest. An extensive quality control and assurance program was designed for use with these methods. Some validation work on serum was done using radiolabeled 14C-Aroclor 1254. Dilution assays were developed to permit use of a constant procedure, which should minimize variability in results. Methods are based on selected organic solvent extraction and column chromatographic cleanup techniques and quantitation by electron capture gas chromatography (EC/GC). Using these extensively researched extraction and cleanup methods, the limits of detection for GC measurements were 10.0 and 2.00 ppb for PCBs and DDE, respectively, in milk and 4.00 and 0.80 ppb in serum.
Liquid Chromatographic Separation and Fluorometric Determination of Quaternium-15 in Cosmetics
Authors: Stack Ann R , Davis Henry M 
Published: February 2020

Abstract
A method is described for the determination of the cosmetic preservative quaternium-15 (cis-l-(3-chIoroallyl)-3,5,7-triaza-l-azoniaadamantane chloride) in the presence of free formaldehyde, 2-bromo-2- nitro-l,3-propanediol, and imidazolidinyl urea. Quaterium-15 is separated from the other preservatives in cosmetic products by using liquid chromatography on a pellicular reverse phase C18 column. Formaldehyde released from the eluted quaternium-15 reacts with ammonium acetate-buffered 2,4-pentanedione reagent in a heated reaction coil to form the highly fluorescent post-column derivative 3,5-diacetyl-l,4-dihydrolutidine. A minimum of 1 μg quaternium-15/mL (0.001%) is detected by fluorescence. Recoveries of quaternium-15 from samples of a lotion, a body detergent, and a mascara spiked at 0.01, 0.1, and 0.2% ranged from 94 to 106% and averaged 100%.