Showing papers in "Journal of AOAC International in 1981"
TL;DR: A sensitive, reliable, and economical method for the determination of 6 mycotoxins in mixed feeds is described and has been applied to a wide range of mixed feeds, including laboratory animal diets, and raw materials.
Abstract: A sensitive, reliable, and economical method for the determination of 6 mycotoxins in mixed feeds is described. The feed is extracted with chloroform-water and the extract is cleaned up by using a disposable Sep-Pak silica cartridge. The procedure requires less time (15 min from sample extraction to extract preparation) and less solvent (approximately one-tenth) compared with conventional methods and is suitable for a fast, economical screen. Additional cleanup procedures, involving dialysis or extraction into base, are described for samples containing high levels of interfering compounds. Thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with fluorescence detection are described for identification and estimation of mycotoxins. The method has been applied to a wide range of mixed feeds, including laboratory animal diets, and raw materials. The limit of detection is 1 microgram/kg for all mycotoxins measured by HPLC.
89 citations
TL;DR: The glucose, fructose, sucrose, and sorbitol content of apple, pear, plum, cherry, grape, strawberry, raspberry, blackberry, and peak fruit was compiled from the literature; their range, mean, standard deviation, and percent coefficient of variance were calculated.
Abstract: The glucose, fructose, sucrose, and sorbitol content of apple, pear, plum, cherry, grape, strawberry, raspberry, blackberry, and peak fruit was compiled from the literature; their range, mean, standard deviation, and percent coefficient of variance were calculated. The individual fruits have characteristic patterns relating to their sorbitol content, glucose: fructose ratio, and sucrose content which are influenced to only a small degree by variety, season, or geographic origin. Processing in many cases has a marked effect on sucrose content.
84 citations
58 citations
53 citations
TL;DR: Ground spices and herbs are evaluated as substrates for mycelial growth, sporulation, and aflatoxin production and there were definite strain differences and definite substrate differences for the variables evaluated.
Abstract: Ground spices and herbs are evaluated as substrates for mycelial growth, sporulation, and aflatoxin production. Three toxigenic strains of Aspergilli, A. flavus ATCC 15548, A. flavus NRRL 3251, and A. parasiticus NRRL 2999, were cultured on moist, commercially packaged herbs and spices. All substrates used were ground and included thyme, celery seed, oregano, cinnamon, ginger, caraway seed, clove, mustard, sesame seed, and rosemary leaves. Following inoculation of the natural materials in sterile bottles containing sterile water, the cultures were incubated 30 days at 23 +/- 4 degrees C. Not all strains of Aspergilli grew, sporulated, or produced toxins. There were definite strain differences and definite substrate differences for the variables evaluated. Sesame seed produced toxins B1, G1, and G2, with a mean of 167 ppm for 3 strains. A. flavus ATCC 15548 was the greatest overall toxin producer followed by A. parasiticus NRRL 2999 and A. flavus NRRL 3251. Ginger and rosemary leaves were also substantial producer-substrates. Mustard, caraway seed, and celery seed were judged as intermediate-producing substrates. Absolute antimycotic substrates were cinnamon and clove. Antiaflatoxigenic substrates were thyme and oregano. Mustard also may be antimycotic. Aflatoxins B1 and G1 were the more commonly found toxins.
51 citations
40 citations
TL;DR: From analyses of the products for aflatoxins before and after preparation of the table-ready products, it was determined that 72 +/- 9% of the aflatoxin found in the original grits could be recovered after the grits were boiled.
Abstract: Corn grits naturally contaminated with aflatoxins were used for making boiled grits, and portions of the boiled grits were used for making pan-fried grits; cornmeal naturally contaminated with aflatoxins was used for making corn muffins. Procedures and recipes were derived from cookbook and market package recommendations. From analyses of the products for aflatoxins before and after preparation of the table-ready products, it was determined that 72 +/- 9% (n = 15) of the aflatoxin found in the original grits could be recovered after the grits were boiled. The recovery of aflatoxin B1 after the grits were fried was either 66 +/- 10% (n = 6) or 47 +/- 8% (n = 9), depending on whether 3 cups of water or 4 cups of water per cup of grits, respectively, were used for preparing the boiled grits before frying. Similarly, it was determined that 87 +/- 4% (n = 9) of the aflatoxin B1 found in the original cornmeal could be recovered from the baked muffins. No detectable aflatoxin B2 a was present in the extracts from any of the table-ready products.
32 citations
TL;DR: The median values for the Canadian drinking water supplies were well below the maximum permissible limits set by Health and Welfare Canada and the World Health Organization.
Abstract: Results of a national survey to ascertain the levels of cadmium, cobalt, chromium, copper, nickel, lead, zinc, calcium, and magnesium in Canadian drinking water supplies are presented. Raw, treated, and distributed water samples collected from 71 municipalities were analyzed by direct atomic absorption spectrophotometry and by an extraction procedure. Trace amounts of all metals, except copper and zinc, were minimal in treated and distributed water. Median values for drinking water supplies were well below the maximum permissible limits set by Health and Welfare Canada and WHO.
26 citations
21 citations
20 citations
TL;DR: A reverse phase high performance liquid chromatographic (HPLC) assay for the quantitative determination of cyanuric acid in urine and water is described, and an external standard is used for quantification by peak height comparison.
Abstract: A reverse phase high performance liquid chromatographic (HPLC) assay for the quantitative determination of cyanuric acid (CA) in urine and water is described. For purification, samples are passed through a pre-activated reverse phase C18 column. The effluent is dried by lyophilization, and the residue is reconstituted in hexane-washed water and then passed through a prewashed Dowex-1 column. The effluent is again dried by lyophilization, and the dry residue is extracted with hot dioxane. The solution is cooled to ambient temperature and centrifuged. The supernatant liquid is removed, dried under a nitrogen steam, and dissolved in water for final extraction by reverse phase chromatography. This effluent is dried, dissolved in the sodium phosphate monohydrate in methanol (pH 7.0) mobile phase, and injected into a pre-equilibrated chromatographic system. An external standard is used for quantification by peak height comparison. A sample of HPLC column effluent is collected, dried, dissolved in methanol, and used for mass spectrometric confirmation by a solid probe insert procedure. Average combined recovery determined at 1.0, 5.0 and 10.0 micrograms CA/mL is 103 +/- 3% with an average coefficient of variation of 8.6%. Standard deviations for the 3 concentration levels are 0.04, 0.58, and 0.76, respectively, with average precisions of 4.28, 10.92, and 7.61%. The limits of detection are approximately 0.05 micrograms/mL for urine and 0.1 micrograms/mL for swimming pool water. Recorder response to CA is linear over the concentration range 1-10 microgram/mL.
TL;DR: A quantitative procedure widely used in European Economic Community (EEC) countries has been successfully scaled down to produce a rapid method for determination of aflatoxin B1 (and other aflatoxins) in animal feeds.
Abstract: A quantitative procedure widely used in European Economic Community (EEC) countries has been successfully scaled down to produce a rapid method for determination of aflatoxin B1 (and other aflatoxins) in animal feeds. Without modification, the method may be used for simultaneous ochratoxin A determination in simple feeds, but a slightly different extraction procedure is required for compound feeds. Validity of the method has been demonstrated by comparison with the full EEC procedure for aflatoxin B1 and the Nesheim method for ochratoxin A. Analyses may be completed within 2 h and there is a considerable savings in materials over the 2 reference methods. The procedure is also less hazardous because volumes of toxic extract are small, and the operator is exposed to minimum solvent vapor.
TL;DR: A simplified apparatus has been applied to the determination of mercury by cold vapor generation and the average mercury recovery was 103% with the ICP, and 99%, with the UV monitor and with atomic absorption, which is free from interference by elements commonly present in biological material.
Abstract: A simplified apparatus has been applied to the determination of mercury by cold vapor generation. The equipment consists of a reaction flask incorporating a side arm in which a rubber septum is mounted. A sample solution is injected from a syringe through the rubber septum into the reaction flask, where it is mixed with a stannous chloride reducing solution. The elemental mercury generated is then swept with a carrier gas to the inductively coupled plasma (ICP), an absorption cell of an atomic absorption spectrometer, or a nondispersive UV monitor for determination. Detection limits were 0.009 and 0.005 micrograms with atomic absorption and the UV monitor, respectively, and 0.09 micrograms with the ICP. Repeatability of the procedure was 1.4% at 0.66 micrograms injected mercury with the ICP and 5.2% at 0.45 micrograms injected with atomic absorption. Tuna and halibut samples fortified with from 0.09 to 1.31 micrograms mercury/g were analyzed by the AOAC official method and the procedure described here. The average mercury recovery was 103% with the ICP, and 99% with the UV monitor and with atomic absorption. The procedure is free from interference by elements commonly present in biological material.
TL;DR: Methods adopted by the AOAC and the American Association of Cereal Chemists for determining aflatoxin in corn were modified, and techniques were developed for application to samples of less than 1 to 10 g instead of the specified 50 g samples.
Abstract: Methods adopted by the AOAC and the American Association of Cereal Chemists for determining aflatoxin in corn were modified, and techniques were developed for application to samples of less than 1 to 10 g instead of the specified 50 g samples. Analysis included chloroform extraction of dust samples or dust collected from glass fiber filters, purification of extracts on a silica gel column of appropriate size, and measurement of aflatoxin by either 1- or 2-dimensional thin layer chromatography (TLC). The solvent for 1-dimensional TLC was chloroform-acetone-water (91 + 9 + 1). Solvents for 2-dimensional TLC were, first direction, ether-methanol-water (95 + 4 + 1, lined tank) and second direction, chloroform-acetone-water (91 + 9 + 1, unlined tank), or first direction, chloroform-acetone-water (91 + 9 + 1, unlined tank) and second direction, toluene-ethyl acetate-formic acid (60 + 30 + 10, unlined tank). When samples weighed less than or equal to 0.1 g, the entire concentrated extract was applied to the TLC plate. About 0.5-1.0 ng aflatoxin B1 could be detected on the plate, making the limit of detection about 9 ng/g for 0.1 g samples.
TL;DR: Both ground fish and cored fish specimens were successfully analyzed by this technique and the overall average recovery for 39 volatile compounds studied was 77% with an average standard deviation of 20%.
Abstract: A technique has been developed for the determination of volatile organic compounds in fish. The methodology is based on procedures used to determine purgeable organic compounds in water and wastewater. Fish tissue is added to reagent water, cooled in an ice bath, and homogenized with cell disruption using ultrasonic energy. The processed sample is then analyzed by a purge and trap procedure using an impinger-type device at 70 degrees C, with determination of the purged compounds by computerized gas chromatography-mass spectrometry. Both ground fish and cored fish specimens were successfully analyzed by this technique. The overall average recovery for 39 volatile compounds studied was 77% with an average standard deviation of 20%.
TL;DR: A modified spectrophotometric method for measuring indole in shrimp is described in this article, which was developed to eliminate the time-consuming steam distillation and expensive instrumentation required by the official AOAC methods.
Abstract: A modified spectrophotometric method for measuring indole in shrimp is described. The method was developed to eliminate the time-consuming steam distillation and expensive instrumentation required by the official AOAC methods. Indole is extracted with light petroleum from trichloroacetic acid-precipitated shrimp muscle. The extracted indole, soluble in light petroleum, is reacted and re-extracted with Ehrlich's reagent; indole in the form of a rose indole complex can be determined spectrophotometrically. When shrimp at various degrees of decomposition were analyzed for indole by the modified method as well as by the official AOAC colorimetric method, the correlation coefficient between the data from the 2 methods was 0.98.
TL;DR: In this article, it has been suggested that the total capsaicinoids be accepted as an index of pungency, which is an important quality index of capsicums and can be reliably estimated by a simple and rapid paper chromatographic method.
Abstract: Total capsaicinoids is an important quality index of capsicums. It has been recommended that this index can be reliably estimated by a simple and rapid paper chromatographic method. Details of the method have been critically studied to establish the precision and reproducibility. Repeatability and reproducibility of the method were plus/minus3.12% and plus/minus6.63% (relative to mean), resp. In addition, the values by this method for samples of capsicums and their oleoresins, varying over a wide range of capsaicinoids content, were validated by a high correlation (r approx. = 1) to pungency values by the standardized threshold dilution method. In the light of the results presented, it is suggested that the total capsaicinoids be accepted as an index of pungency.
TL;DR: A hydrogen selenide (H2Se) evolution-electrothermal atomic absorption method is described for determining nanogram concentrations of total selenium (Se) in biological and environmental materials.
Abstract: A hydrogen selenide (H2Se) evolution-electrothermal atomic absorption method is described for determining nanogram concentrations of total selenium (Se) in biological and environmental materials. A mixed acid digestion procedure is used to decompose organic material. Sodium borohydride, a redesigned hydride generator, and an electric-headed absorption tube are used for H2Se evolution and conversion to atomic Se. The method has a detection limit of 4 ng/mL and a sensitivity of 0.6 ng/mL, and is linear from 0 to 90 ng Se/mL. As determined on urine, water, and bovine liver, total and within-run precision had relative and standard deviation values of 5-17.2 and 5.5-12.6% respectively. Accuracy was established with 2 NBS and 3 EPA reference materials, and mean errors of 0 to +0.8 were obtained. Mean recoveries of 109 and 101% were obtained for 10 and 50 ng Se added to human urine.
TL;DR: The method was compared with 4 other procedures and was superior to alkaline dry ashing methods and the recovery of 125I added to milk and carried through the method ranged from 96 to 102%.
Abstract: A method for determining iodine in food is described. The samples were digested using a mixture of sulfuric, nitric, and perchloric acids. The iodine was determined by an automated colorimetric method based on the iodide-catalyzed reduction of Ce+4 by As+3. For milk samples, the relative standard deviation for the method was less than 3%, and the recovery of 125I added to milk and carried through the method ranged from 96 to 102%. The method was compared with 4 other procedures and was superior to alkaline dry ashing methods.
TL;DR: Both methods were applied to the determination of fructose, glucose, sucrose, maltose, and lactose in processed foods and recovery studies showed better accuracy for the HPLC method.
Abstract: A method has been developed for separation and determination of 5 sugars in foods. Mixtures of sugars were separated by high pressure liquid chromatography (HPLC) with a muBondapak/carbohydrate column and acetonitrile-water (80 + 20) as the mobile phase. For the gas-liquid chromatographic (GLC) determination, the sugars were reacted with hydroxylamine hydrochloride to give the oximes, which were then converted to trimethylsilyl derivatives. The derivatives were separated on an 8 ft column containing 3% JXR as the liquid phase. The GLC preparative time was considerably longer than that for HPLC. Both methods were applied to the determination of fructose, glucose, sucrose, maltose, and lactose in processed foods. Recovery studies showed better accuracy for the HPLC method. Because of incomplete derivatization and/or the formation of anomers, the GLC method was not applicable to all foods.