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Showing papers in "Journal of AOAC International in 1983"


PatentDOI
TL;DR: In this paper, a conveyor system for delivering vials (5) containing samples for analysis through an entry gate and identification arrangement to a series of analytical modules (4a-c) where a succession of tests is effected on each of the samples.
Abstract: The apparatus comprises a conveyor system (1) for delivering vials (5) containing samples for analysis through an entry gate (2) and identification arrangement (3) to a series of analytical modules (4a-c) where a succession of tests is effected on each of the samples. Each of the analytical modules (4a-c) comprises a sample probe, a reagent probe, a container for reagent adjacent to the conveyor means (1), a movable stop member (40) arranged to hold a vial (5) in an appropriate position adjacent to the module, means for moving the movable stop member so as to allow the vial (5) to pass from one module to the next, and means for moving the sample and reagent probes between a first position where they are ready for insertion into a vial (5), and a second position where they are held clear of the vial (5). The apparatus also includes synchronising means arranged to co- ordinate operation of the various elements of the apparatus. In the method, the vials (5) pass sequentially through the entry gate (2) of the above apparatus at a predetermined rate, and a portion of each of the samples is extracted while the vial (5) is at an analysis station adjacent to one of the analytical modules (4a-c). A portion of reagent is simultaneously extracted and is combined with the extracted sample into a single flow line. The combined reagent/sample is subjected to an analytical test within the module.

70 citations


Journal ArticleDOI
TL;DR: 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 to serve as a data base for the detection of fraudulent or adulterated apple juice.
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.

59 citations


Journal ArticleDOI
TL;DR: A gas chromatographic method is described for the analysis of human milk to determine polychlorinated biphenyls (PCBs) as 72 congeners plus p,p'-DDE, mirex, hexachlorobenzene, and octachlorostyrene.
Abstract: A gas chromatographic method is described for the analysis of human milk to determine polychlorinated biphenyls (PCBs) as 72 congeners plus p,p'-DDE, mirex, hexachlorobenzene, and octachlorostyrene. The detection limit for individual compounds is about 0.05 ng/g when 30 g milk is analyzed. Total PCBs can be estimated with a detection limit of 1-5 ng/mL milk. Analytical precision is better than +/- 10% for all compounds at 20-50 ng/mL whole milk.

34 citations


Journal ArticleDOI
TL;DR: A noncompetitive, double antibody enzyme-linked immunosorbent assay for ochratoxin A using microtitration plates has been developed and applied to samples of barley, and sensitivity for determination of the toxin in barley samples is 60 ng/kg.
Abstract: A noncompetitive, double antibody enzyme-linked immunosorbent assay for ochratoxin A using microtitration plates has been developed and applied to samples of barley. The anti-ochratoxin A antiserum, which is used at high dilution, does not cross-react significantly with ochratoxin B or ochratoxin a. Assay sensitivity for determination of the toxin in barley samples is 60 ng/kg. Minimal sample preparation is required before assay.

31 citations




Journal ArticleDOI
TL;DR: The results suggest that the fish extracts can be screened for AHH inducers before chemical analysis, and suggest that an optimal dose-response range was determined and used to estimate TCDD equivalents.
Abstract: A sensitive biological test to detect the presence of certain contaminants, such as highly toxic halogenated dioxins, dibenzofurans, and biphenyls in foods, was applied to extracts of fresh water fish that had been prepared by a food extraction-cleanup procedure developed by the Food and Drug Administration for pesticides and industrial chemicals. Aryl hydrocarbon hydroxylase (AHH) activity in a rat hepatoma cell line was used as the biological detection system for residues that induce enzyme activity. The induction of AHH activity by the extracts was compared with a standard AHH-induction curve for the most active compound known, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and results were computed as TCDD equivalents. Several dilutions of fish extracts were used to produce AHH-induction curves from which an optimal dose-response range was determined and used to estimate TCDD equivalents. Cleaned-up extracts of fish obtained from different water bodies in the United States were examined for AHH activity. The samples which had low levels of polyhalogenated contaminants produced low biological activity, while a higher activity was obtained from fish that contained higher levels of polyhalogenated contaminants. The results suggest that the fish extracts can be screened for AHH inducers before chemical analysis.

28 citations



Journal ArticleDOI
TL;DR: A method was developed for the determination of aflatoxin B1 in commercially prepared feeds that is more rapid and less involved than most previously published methods for mixed feeds.
Abstract: A method was developed for the determination of aflatoxin B1 in commercially prepared feeds. The method incorporates methylene chloride and citric acid solution extraction, cleanup on a small silica gel column, and thin layer chromatography for quantitation. Commercial turkey starter, catfish chow, medicated pig starter, broiler finisher, rabbit chow, horse feed, rat chow, and dog chow were investigated. The feeds were spiked with naturally contaminated corn at 4 different levels of aflatoxin B1 (16-130 microgram/kg). Three assays were run on each of the 32 combinations of feed and levels of aflatoxin. Mean recoveries were 85.9-92.8% at levels of 16.5, 32.9, 65.8, and 131.6 micrograms/kg. The relative standard deviation per assay was 18.6%. This method is more rapid and less involved than most previously published methods for mixed feeds.

22 citations



Journal ArticleDOI
TL;DR: A method was developed for the simultaneous determination of 6 Fusarium mycotoxins (deoxynivalenol, diacetoxyscirpenol, HT-2 toxins, T-2 toxin, fusarenon-x, and zearalenone) and Kováts' retention index was determined.
Abstract: A method was developed for the simultaneous determination of 6 Fusarium mycotoxins (deoxynivalenol, diacetoxyscirpenol, HT-2 toxin, T-2 toxin, fusarenon-x, and zearalenone). Cereal samples were first extracted with ethyl acetate, then with a mixture of methanol-water. The crude extracts were combined and purified by silica gel chromatography. The purified extract was reacted with BSTFA (N,O-bis(trimethylsilyl)-trifluoroacetamide) to form the derivative, and chromatographed on an SE-52 wall-coated open tubular column. Kovats' retention index was determined for the 6 mycotoxins investigated. Recoveries and standard deviations were determined for pure toxin mixed in cereal. Recovery was 70-80%; relative standard deviation was 10-18%. The method developed was applied to different cereal samples.


Journal ArticleDOI
TL;DR: A rapid method is described for determining zearalenone in corn, sorghum, and wheat by thin layer chromatography and identity is confirmed with various developing solvents and spray reagents.
Abstract: A rapid method is described for determining zearalenone in corn, sorghum, and wheat. The mycotoxin is extracted with a mixture of acetonitrile and 4% KCl in HCl. The extract is cleaned up with isooctane, evaporated, and redissolved in chloroform. Zearalenone is separated by thin layer chromatography; identity is confirmed with various developing solvents and spray reagents. Zearalenone is then quantitated by the limit detection method. The minimum detectable concentration is 140-160 micrograms/kg when aluminum chloride solution is used as spray reagent, and 85-110 micrograms/kg when Fast Violet B salt is used as spray reagent.



Journal ArticleDOI
TL;DR: Proximate data indicate that NIR can be used to estimate moisture, fat, lactose, and protein content of NFDM.
Abstract: Proximate data from 82 nonfat dry milk (NFDM) samples were correlated with near infrared reflectance (NIR) measurements. The best wavelengths for determining constituent concentrations were chosen from 19 preselected filters by using linear regression analysis. The correlation coefficient (r) was 0.971 and the standard error of prediction (SEP) was 0.274 when the predicted values (from NIR measurements) using the 3 wavelengths selected for determining moisture content were compared with laboratory values; r and SEP were 0.961 and 0.099, respectively, when the predicted values using the 4 wavelengths selected for fat content were compared with laboratory results; 0.887 and 0.594, respectively, using the 4 wavelengths selected for lactose content; 0.905 and 0.438 using the 8 wavelengths selected for protein (micro-Kjeldahl) content; and 0.911 and 0.509 using the 7 wavelengths selected for protein (dye binding). These data indicate that NIR can be used to estimate moisture, fat, lactose, and protein content of NFDM.



Journal ArticleDOI
TL;DR: A method is proposed for concurrently determining the levels of multiple intact exogenous compounds in serum, particularly polychlorinated biphenyls (PCBs) as Aroclor (AR) 1254 and chlorinated hydrocarbons (CHs) and in vitro-spiked CHs.
Abstract: A method is proposed for concurrently determining the levels of multiple intact exogenous compounds in serum, particularly polychlorinated biphenyls (PCBs) as Aroclor (AR) 1254 and chlorinated hydrocarbons (CHs). Bovine serum pools containing in vivo-bound PCBs (as AR 1254) and in vitro-spiked CHs are used to evaluate the method, which encompasses serum denaturation with methanol, mixed solvent extraction, multiple solvent fractionation from activated silica gel, and determination by electron capture gas-liquid chromatography. Mean recoveries of the in vitro-spiked 9 CHs at levels of 2.0-29.1 ppb ranged from 52.8 to 98.4% from trial environmental pools; mean recoveries of the in vivo-bound PCBs (as AR 1254) were 114.1 and 92.6% at levels of 10 and 50 ppb, respectively.

Journal ArticleDOI
TL;DR: Dyes are determined in gelatin-containing sweets by thin layer chromatography and high performance liquid chromatography (HPLC), and quantitated by HPLC or colorimetry.
Abstract: Dyes are determined in gelatin-containing sweets. The gelatin must be eliminated first because it interferes with the normal ion-pair extraction of dyes with tri-n-octylamine to chloroform. Techniques such as precipitation of gelatin with organic solvents, and acid and enzymatic digestion of gelatin are shown to be unsuccessful because the remaining gelatin still influences the extraction scheme. Positive results are obtained when dyes are adsorbed on polyamide, gelatin is washed away, and dyes are desorbed with a methanol-ammonia mixture. Dyes are identified by thin layer chromatography and high performance liquid chromatography (HPLC), and quantitated by HPLC or colorimetry.

Journal ArticleDOI
TL;DR: Every year during the 5-year period 1976-1980, approximately 100 samples each of corn and wheat from trucks delivering the grains at elevators in Virginia were collected by personnel of the Federal Grain Inspection Service and shipped to NRRC for aflatoxin, zearalenone, and ochratoxin A.
Abstract: Every year during the 5-year period 1976-1980, approximately 100 samples each of corn and wheat from trucks delivering the grains at elevators in Virginia were collected by personnel of the Federal Grain Inspection Service and shipped to NRRC. Samples were analyzed as soon as possible for aflatoxin, zearalenone, and ochratoxin A. The 3 mycotoxins were not detected in any wheat sample. Zearalenone and ochratoxin A were not found in any corn sample; however, aflatoxin was detected in at least 25% of the corn samples from every crop year. In 1976-1980, the incidence of aflatoxin at levels of 20 ng/g or more (the Food and Drug Administration guideline) ranged from 18 to 61%; aflatoxin incidence above 100 ng/g was 5-29%. The average aflatoxin levels in corn samples collected in the 5 years varied from 21 to 137 ng/g. Moisture content of the samples was not determined, so aflatoxin levels given may be higher than they were at harvest. However, there are obviously differences from year to year. In freshly harvested corn samples collected by fieldmen of the Statistical Reporting Service in yield surveys in 1978 and 1979, aflatoxin incidence above the FDA guideline was 10 and 13%, and above 100 ng/g was 4 and 7%. The average aflatoxin level in all samples collected in 1978 was 13 ng/g and in 1979, 36 ng/g. Some aflatoxin can be expected yearly in Virginia corn, but the incidence and levels vary from year to year.



Journal ArticleDOI
TL;DR: Sulfathiazole residues were extracted from honey by homogenizing samples in acetone, filtering, and then evaporating the acetone under nitrogen at 40 degrees C.
Abstract: Sulfathiazole residues were extracted from honey by homogenizing samples in acetone, filtering, and then evaporating the acetone under nitrogen at 40 degrees C. The remaining extract was transferred to a separatory funnel with 1N HCl and ethyl ether. An aliquot of the retained acid layer was screened by using the Bratton-Marshall reaction. If the test was positive, the remaining portion was analyzed directly through a mu Bondapak phenyl column monitored by a UV detector at 254 nm. The mobile phase was potassium phosphate monobasic in 10% acetonitrile adjusted to pH 3.0. Time for elution was 13 min. Average recoveries were 78% at the 0.1 ppm spiking level and 68% at the 1.0 ppm level. The minimum detectable amount was 0.06 ppm based on a spiked sample extract.





Journal ArticleDOI
TL;DR: In-situ optical scanning of fluorescamine derivatives on thin layer silica gel plates provides a rapid method for the determination of multiple sulfonamides at levels below 1 ppm Sample preparation is minimal Homogenized liver or muscle is extracted with ethyl acetate and then back-extracted into 02M glycine buffer After pH adjustment, the extract is washed with hexane and extracted with methylene chloride The organic phase is evaporated to dryness and reconstituted in methanol Pre-adsorbent layer gel plates are used for chromatography The method has
Abstract: In-situ optical scanning of fluorescamine derivatives on thin layer silica gel plates provides a rapid method for the determination of multiple sulfonamides at levels below 01 ppm Sample preparation is minimal Homogenized liver or muscle is extracted with ethyl acetate and then back-extracted into 02M glycine buffer After pH adjustment, the extract is washed with hexane and extracted with methylene chloride The organic phase is evaporated to dryness and reconstituted in methanol Pre-adsorbent layer silica gel plates are used for chromatography The method has been applied to residues of sulfamethazine, sulfadimethoxine, sulfathiazole, sulfaquinoxaline, and sulfabromomethazine in cattle, swine, turkey, and duck tissues