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1.
High pressure liquid chromatographic determination of aflatoxins in corn.   总被引:1,自引:0,他引:1  
A high pressure liquid chromatographic (HPLC) method is proposed for determining aflatoxins in corn. The sample is extracted with methanol-10% NaCl (4 + 1), pigments are precipitated with zinc acetate, and the extract is cleaned up on a small (2 g) silica gel column. Aflatoxins in the purified extract are resolved by normal phase HPLC on a microparticulate (10 micrometer) silica gel column with water-saturated chloroform-cyclohexane, acetonitrile solvent, and detected by fluorescence on a silica gel-packed flowcell. The method was compared with chloroform-water extraction of the official CB method on 15 samples of contaminated corn. In 5 of the 6 samples containing aflatoxins B1, B2, G1, and G2, methanol-10% NaCl extracted more aflatoxin than did cloroform-water, as measured both by HPLC and by thin layer chromatography. In samples containing only B1 and B2, the 2 extraction solvents were virtually equivalent. Agreement was good between HPLC and TLC for each extraction solvent. Average recovery of aflatoxins B1, B2, G1, and G2 added to yellow cornmeal at 3 levels was greater than 90%.  相似文献   

2.
High pressure liquid chromatographic determination of arprinocid in feed.   总被引:1,自引:0,他引:1  
Arprinocid [9 - (2 - chloro - 6 - fluorophenylmethyl)-9H-purin-6-amine] is determined in feed by high pressure liquid chromatography with a silica column and ultraviolet detection. The drug is extracted from the feed into chloroform in the presence of pH 7 phosphate buffer, transferred to 0.1N HCl, and separated from interfering substances by partitioning with hexane. The acidic solution is neutralized, and the analyte is extracted into chloroform for injection into the chromatograph. This procedure has been applied to feeds containing 0.0030--0.0090% arprinocid with a precision of less than 5% relative standard deviation at the 0.0060% formulated concentration level. The results of this chromatographic procedure also correlate with those from a colorimetric analysis.  相似文献   

3.
A rapid high pressure liquid chromatographic (HPLC) screening method for the quantitative determination of nitrofurazone in milk has been developed. The drug is extracted with ethyl acetate from a 2.0 ml milk serum sample, the organic layer is evaporated to dryness, and the residue is dissolved in the mobile phase and injected into the liquid chromatogarph. A reverse phase muBondapak C18 column is used with monitoring at 365 nm. The detection limit is 5 ppb and recoveries are 57--67%. Mass spectroscopic confirmation of the HPLC nitrofuran peak is described.  相似文献   

4.
A high pressure liquid chromatographic method for determining furazolidone in turkey tissue has been developed. Tissues are ground with methanol and centrifuged. For lower levels of furazolidone, 2--40 ppb, the supernate is evaporated to dryness and redissolved before it is injected onto the liquid chromatographic column. Using a reverse phase column and an ultraviolet absorption detector set at 365 nm, the assay is linear over the concentration range 2--400 ppb with a coefficient of variation of less than 4%. Average recovery from fortified tissues was 96% with a coefficient of variation of 6% at the 50--400 ppb level, and 105% with a coefficient of variation of 11% at the 2--40 ppb level.  相似文献   

5.
A high pressure liquid chromatographic (HPLC) method has been developed which is fast, simple, specific, and reliable over a wide range of sugar concentrations in a variety of food matrices. With few exceptions, sample preparation is simple, requiring only a water-ethanol extraction, followed by a rapid mini-column cleanup before injection into the HPLC system. The majority of samples can be prepared for analysis within 1--1 1/2 hr, and the following sugars are separated in less than 45 min: fructose, glucose, sucrose, maltose, lactose, melibioals, chocolate products, chocolate sirups, cookies, health food products, molasses, preserves, processed fruits, and soy protein products.  相似文献   

6.
A high pressure liquid chromatographic (HPLC) procedure is described for determining 13 polynuclear aromatic hydrocarbon (PNA) compounds in oysters at the 2 ppb level. These compounds are extracted from shellfish with acetonitrile and partitioned into petroleum ether; the petroleum ether is removed and the residue is saponified. The aromatic compounds are isolated by passing the saponifeid residue through silica gel and further purified and fractionated by muStyragel gel permeation chromatography. The in-ividual PNAs are then quantitatively determined by using a reverse phase HPLC column coupled to fluorescence, spectrophotometric, and 254 nm absorbance detectors in series. Recoveries from spiked samples generally were greater than 80%.  相似文献   

7.
A method is reported for the extraction and analysis of zearalenone in chicken fat, heart muscle, and kidney tissue by using high pressure liquid chromatography (HPLC). Zearalenone is extracted with acetonitrile, cleaned up with hexane, and extracted further with ethyl acetate. Zearalenone is determined by HPLC using a reverse phase radial compression separation system, an ultraviolet absorbance detector, and a mobile phase of acetonitrile-water (60 + 40) (v/v). Recoveries of zearalenone added at levels from 50 to 200 ng/g are in the range 82.6-95.1%.  相似文献   

8.
9.
A high pressure liquid chromatographic (HPLC) method has been developed for determining ochratoxin A and zearalenone in cereals. The sample is extracted with phosphoric acid and chloroform. The extract is cleaned by washing on a silica gel column with cyclohexane-ethylene dichloride-ethyl ether. After eluting zearalenone with chloroform, ochratoxin A is eluted with chloroform-formic acid. Zearalenone is extracted into alkaline solution, washed with chloroform, the pH is adjusted, and the zearalenone is extracted back into chloroform. Ochratoxin A is purified by chromatography on aqueous sodium biarbonate-Celite. The mycotoxins are determined by using a liquid chromatograph with 2 columns in series packed with Spherisorb ODS 10 micrometer and 5 micrometers, respectively. Ochratoxin A is detected with a speftrophotofluorometer, coupled in series with an ultra-violet detector for estimation of zearalenone. Detection limits are 1-5 micrograms/kg for ochratoxin A and 2 micrograms/kg for zearalenone.  相似文献   

10.
A rapid method for the simultaneous determination of vitamins A and E in fortified cereal products has been developed. Saponification of retinyl or tocopheryl esters is not required, permitting direct injection of the extracted lipids onto the high pressure liquid chromatographic column without sample cleanup. Elution times of 2.46 and 3.40 min were determined for retinyl palmitate and tocopheryl acetate, respectively, using a muPorasil column and an isocratic mobile phase of hexane-chloroform (85 + 15) with a flow rate of 1.5 mL/min. The average recovery of retinyl palmitate was 99.2% (std dev. 4.28), and the average recovery of tocopheryl acetate was 94.9% (std dev. 4.10) in 2 cereals containing corn, oat, rice, and wheat. No significant amounts of naturally occurring tocopherols were found in the cereals.  相似文献   

11.
Vitamin D3 is determined in livestock feed supplements by high pressure liquid chromatography (HPLC). Extracts of the samples are quantitated using normal phase chromatography. If interfering co-extractives are present, an aliquot of the extract is injected on the normal phase column, and the fraction corresponding to vitamin D3 is collected. The vitamin fraction is then further cleaned up and separated from interferences by reverse phase chromatography, and quantitated by measuring the ultraviolet absorption at 254 and 280 nm. The method measures actual vitamin D3 content in the presence of pre-vitamin D, tachysterol, isotachysterol, and vitamin A.  相似文献   

12.
A method is presented for the quantitative analysis of o-phenylphenol residues in citrus oils, encapsulated flavors, and dried meal. The method utilizes high-speed liquid chromatography for the determination after specific sample preparations for each material. These preparations include hexane extraction of acidified basic extracts or steam distillation and extraction. The limit of the analysis is less than 1 ppm with an analysis time of less than 45 min.  相似文献   

13.
A simple, direct, and rapid method is given for the analysis of citrus oils for the fungistat biphenyl by high-speed liquid chromatography. The method is extended to orange juice and various "dry flavors" by an extraction procedure. Analytical limits are less than 1 ppm without need for any cleanup or concentration steps.  相似文献   

14.
Fourteen analysts from 9 laboratories evaluated a high pressure liquid chromatographic procedure for the determination of 4,4'-(diazoamino)-dibenzenesulfonic acid (DAADBSA) in FD&C Yellow No. 6. Each collaborator analyzed 5 samples nominally containing 0-0.050% DAADBSA. The repeatability and reproducibility of the method are estimated to be 0.003% and 0.020%, respectively. The method has been adopted as offical fist action.  相似文献   

15.
An HPLC method was developed to determine residues of individual isomers of brodifacoum (3-[3-4'-bromo[1,1'-biphenyl]-4-yl)-1, 2, 3, 4-tetrahydro-1-naphthalenyl]-4-hydroxy-2H-1-benzopyran-2-one) in rat tissue. The compound was extracted twice with 10% methanol in chloroform, filtered, and cleaned up by using automated gel permeation chromatography. A final cleanup on a silica gel SEP-PAK was added to protect the analytical column from irreversible adsorption and to reduce analysis time. The analysis was done on a microPorasil column; a UV detector was used for quantitation. Recoveries of brodifacoum added to rat tissue in concentrations of 0.12-5.0 ppm were greater than 90%.  相似文献   

16.
A reverse phase high pressure liquid chromatographic method in which ion-pairing is used for the determination of combinations of pseudoephedrine hydrochloride with triprolidine hydrochloride or chlorpheniramine maleate in syrups and tablets was collaboratively studied by 8 laboratories. Collaborators were supplied with 12 samples including synthetic and commercial syrup formulations and commercial tablet composites. Mean recoveries of pseudoephedrine hydrochloride and triprolidine hydrochloride from synthetic syrup formulations were 100.5 and 99.6%, respectively. Mean recoveries of pseudoephedrine hydrochloride and chlorpheniramine maleate from synthetic syrups were 98.8 and 100.5%, respectively. Mean coefficients of variation for syrups and tablets ranged from 1.68 to 3.07% for pseudoephedrine hydrochloride, from 2.92 to 3.85% for triprolidine hydrochloride, and from 1.34 to 2.15% for chlorpheniramine maleate. The method has been adopted official first action.  相似文献   

17.
A reverse phase high pressure liquid chromatographic method for the determination of oxazepam in tablets and capsules was collaboratively studied by 9 laboratories. Collaborators were supplied with 6 samples that included synthetic and commercial formulations. Tablet and capsule composites are diluted with methanol and filtered. Oxazepam is determined at 254 nm by using a C18 column. Mean recoveries of oxazepam from synthetic tablet and capsule formulations were 97.2 and 99.0%, respectively. Mean coefficients of variation for tablets and capsules ranged from 1.85 to 2.86%. The method has been adopted official first action.  相似文献   

18.
A reverse phase high pressure liquid chromatographic method is presented for the separation and determination of residues of the carbamates oxamyl and methomyl on vegetables. A liquid-liquid extraction and cleanup procedure is applied to the vegetable extract. Samples are eluted from a muBondapak C18 column and quantitated by ultraviolet absorbance at 240 nm. Recovery data for vegetable samples spiked at 2 ppm are presented.  相似文献   

19.
A high pressure liquid chromatographic procedure is described for assay of toxins associated with paralytic shellfish poisoning (PSP). The method is applicable to saxitoxin, neosaxitoxin, gonyautoxins I through IV, and their sulfocarbamoyl derivatives. Toxins are separated on a bonded phase cyano column and detected by fluorescence following alkaline oxidation (NH+4 and periodic acid). The utility of the HPLC procedure for research and monitoring is discussed.  相似文献   

20.
A high pressure liquid chromatographic (HPLC) method for determining 5 common carbohydrates in food products was evaluated. Reproducibility data were generated showing a relative standard deviation of 2.8%. Recovery studies on a variety of foods gave an average recovery of 98.8%. The HPLC data for 3 varieties of ready-to-eat cereals were compared with data from 4 independent laboratories using current AOAC chemical methods. The HPLC mean values differed from the chemical mean values by 3.2%.  相似文献   

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