Simplified Method for Microscale Production and Quantification of Aflatoxin in Broth1

1984 ◽  
Vol 47 (7) ◽  
pp. 526-529 ◽  
Author(s):  
WEI-YUN J. TSAI ◽  
JIMMY D. LAMBERT ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Solvent Extraction ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Frozen Storage ◽  
Aflatoxin Production ◽  
Production Studies ◽  
Simplified Method ◽  
Tlc Plates ◽  
Layer Chromatography ◽  
Yeast Extract Sucrose

A simplified method for aflatoxin production studies is described. The mold was cultured in 4-dram (15 ml) vials containing 5 ml of yeast extract sucrose broth, and aflatoxin levels were determined by direct spotting of the broth on thin layer chromatography (TLC) plates and quantitating by spectrodensitometry. Equivalent levels of aflatoxins were produced in vials as compared to flasks. When compared to conventional TLC after solvent extraction, direct spotting was rapid, economical and statistically equivalent. Heating broth cultures (121°C, 15 s) before TLC improved the release of aflatoxin from mycelial mats. Aflatoxins were unstable in YES broth during 3 months of frozen storage.

Susceptibility of Strawberries, Blackberries, and Cherries to Aspergillus Mold Growth and Aflatoxin Production

1982 ◽  
Vol 65 (3) ◽  
pp. 659-664 ◽  
Author(s):  
Gerald C Llewellyn ◽  
Thomas Eadie ◽  
William V Dashek
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Mycelial Growth ◽  
Methylene Chloride ◽  
Aflatoxin Production ◽  
Solvent System ◽  
Mold Growth ◽  
Tlc Plates ◽  
Layer Chromatography

Abstract The susceptibility of blackberries, cherries, and strawberries to Aspergillus growth and aflatoxin production has been examined. Three aflatoxigenic isolates of Aspergillus, A. flavus ATCC 15548 and NRRL 3251 as well as A. parasiticus NRRL 2999, were cultured on homogenates of the fruits for 14 days at 28 ± 2°C. Percent mycelial growth and spore infestation were determined each day with a calibrated grid. At day 14 each culture was frozen at –5°C until aflatoxins were extracted with methylene chloride and water. Aflatoxins were separated by thin layer chromatography (TLC) with benzene-methanol-acetic acid (90 + 5 + 5). This extraction and solvent system provided satisfactory separations of the aflatoxins and was free of background interference on the TLC plates. Although all fruits served as substrates for both Aspergillus growth and aflatoxin production, cherries appeared to be a more favorable substrate than did blackberries, and the latter was more favorable than strawberries. Whereas A. flavus produced both B1 and G1 on all substrates, it yielded B2 and G2 only on cherries. Although A. parasiticus NRRL 2999 synthesized B1, B2, G1, and G2 on both blackberries and cherries, no aflatoxins were detected on strawberries. In contrast, A. flavus NRRL 3251 failed to produce detectable levels of aflatoxin on any substrate. All substrates supported both mycelial growth and subsequent sporulation with cherries > blackberries > strawberries.

Dilution Errors in Aflatoxin Determinations Caused by Compounds Extracted from Peanuts

1983 ◽  
Vol 66 (5) ◽  
pp. 1059-1062
Author(s):  
James W Dickens ◽  
Thomas B Whitaker
Keyword(s):  
Solvent Extraction ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Extraction Solvent ◽  
Water Slurry ◽  
Tlc Plates ◽  
Slurry Method ◽  
Layer Chromatography

Abstract Several methods have been developed to analyze peanuts for aflatoxin by using thin layer chromatography (TLC). These methods depend on solvent extraction of aflatoxin from a sample of the product. Unfortunately, solvent solutions used to extract aflatoxin from peanuts also extract measurable quantities of other compounds such as oils, fats, sugars, and protein. The volume of these extracted compounds causes error in measuring the proportion of the solvent solution analyzed for aflatoxin. Also, because the cleanup procedures for some methods are inadequate, the volume of some of these extracted compounds also causes error in measuring the proportion of the extracted aflatoxin placed on TLC plates. These 2 errors cause underestimation of aflatoxin concentrations by approximately 11,14, and 57c for the CB method, the modified version of the BF method generally used for raw peanuts, and a water slurry method, respectively. The correction specified bytheCB method for fats in the extraction solvent reduces the approximate error for the CB method from 11 to 1%.

Analysis of Dairy Products for Chlorinated Insecticide Residues by Thin Layer Chromatography

1966 ◽  
Vol 49 (4) ◽  
pp. 795-800
Author(s):  
William A Moats
Keyword(s):  
Aluminum Oxide ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Color Development ◽  
Tlc Plates ◽  
One Step ◽  
Rf Values ◽  
Tlc Analysis ◽  
Layer Chromatography

Abstract Butterfat and milk samples were analyzed for chlorinated insecticides by thin layer chromatography (TLC) on aluminum oxide or silica gel plates containing a small amount of silver nitrate. The adsorbent was washed with distilled water before preparing the plates. A one-step cleanup on a partially inactivated Florisil column was performed prior to TLC analysis. For color development, the TLC plates were sprayed lightly with hydrogen peroxide to suppress possible interference from fat and then steamed before exposure to ultraviolet light to accelerate and intensify the color reaction. Rf values for a number of solvent systems on aluminum oxide and silica gel plates are given. With this procedure, 0.05 μg or less of insecticide can be detected in a 0.4 g butterfat sample or the extract from 10 ml milk.

scholarly journals Determination of New Antidepressants in Pharmaceuticals by Thin-Layer Chromatography with Densitometry

2010 ◽  
Vol 93 (3) ◽  
pp. 778-782 ◽  
Author(s):  
Tatána Gondová ◽  
Iveta Petríková
Keyword(s):  
Thin Layer ◽  
Stationary Phase ◽  
Thin Layer Chromatography ◽  
Mobile Phase ◽  
Pharmaceutical Formulations ◽  
Simultaneous Separation ◽  
Tlc Plates ◽  
Precision And Accuracy ◽  
Layer Chromatography

Abstract A new and simple TLC-densitometry method has been developed for the simultaneous separation of the two noradrenergic and specific serotonergic antidepressants mirtazapine and mianserine and validated for their determination in commercially available tablets. The method used TLC plates precoated with silica gel 60F254 as the stationary phase, and the mobile phase consisted of hexaneisopropanol25 ammonia (70 + 25 + 5, v/v/v). Densitometric analysis was carried out in the absorbance mode at 280 nm. The method was validated in accordance with International Conference on Harmonization guidelines in terms of linearity, LOD, LOQ, precision, and accuracy. Calibration curves were linear (R2 > 0.9970) with respect to peak area in the concentration range of 5002500 and 5005000 ng/spot for mirtazapine and mianserine, respectively. The LODs were 20 and 35 ng/spot for mirtazapine and mianserine, respectively. The described method was successfully applied to the determination of mirtazapine and mianserine in their pharmaceutical formulations with recovery ranging from 99.83 to 101.20 of the labeled amount of the compounds. The proposed method can be used in routine QC of these drugs in pharmaceutical formulations.

Computerized System to Quantify Aflatoxin Using Thin Layer Chromatography1

1990 ◽  
Vol 17 (2) ◽  
pp. 96-100 ◽  
Author(s):  
T. B. Whitaker ◽  
J. W. Dickens ◽  
A. B. Slate
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Measurement Errors ◽  
Regression Equation ◽  
Fluorescent Intensity ◽  
Percent Error ◽  
Sample Extract ◽  
Tlc Plates ◽  
Layer Chromatography ◽  
Computerized System

Abstract A microcomputer was interfaced to an instrument (spotmeter) previously designed to measure the fluorescent intensity of aflatoxin spots on thin layer chromatography (TLC) plates. Software was developed that uses a cubic regression equation to describe the relationships between the spotmeter readings and the known quantities of aflatoxin in standard spots on TLC plates. The regression technique also provides methods to detect spotting and/or measurement errors. Based on the regression equation and measurements of sample extract spots on the same TLC plate, the system computes and records the amount of aflatoxin in the sample extract spots and the concentration of aflatoxin that was in the extracted sample. The percent error associated with computed amounts of aflatoxin in sample extract spots is affected by the amount of aflatoxin in the sample extract spots and standard spots on the plate. The average percent error ranged from 14.9% for a 2.6 ng spot of 4.1% for a 13 ng spot.

scholarly journals Some Observations on Thin Layer Chromatography Technique

2019 ◽  
Vol 8 (2) ◽  
pp. 1700-1702
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Potassium Permanganate ◽  
Mobile Phase ◽  
Technical Aspects ◽  
Potassium Permanganate Solution ◽  
Tlc Plates ◽  
Solvent Use ◽  
Layer Chromatography

The present study is to report the various problems faced during TLC methodology. Although used regularly some technical aspects must be kept in mind to get better and uniform results. During our experiments with TLC methods we came across some problems and here these aspects of TLC methodology are being highlighted. It is suggested that the solvent use as mobile phase should also be used for extraction of any particular phytochemical. TLC plates should be 3 to 4 mm thick, to be dried for at least 72 hrs. It is also suggested that potassium permanganate solution gives better clarity in visualizing the spots

Thin-layer chromatography of free porphyrins for diagnosis of porphyria.

1989 ◽  
Vol 35 (6) ◽  
pp. 1043-1044 ◽  
Author(s):  
M J Henderson
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Screening Tests ◽  
Fluorescent Light ◽  
Comprehensive Investigation ◽  
Long Wave ◽  
Tlc Plates ◽  
Layer Chromatography

Abstract In this simple thin-layer chromatographic (TLC) technique for evaluating porphyrin excretion, porphyrins are extracted from urine or feces, then separated on silica-gel TLC plates. The distinct porphyrin bands are observed by viewing the plates under long-wave fluorescent light. Positive screening tests can readily be confirmed or rejected, and a more comprehensive investigation confidently undertaken.

Aspergillus parasiticus Growth and Aflatoxin Synthesis on Florunner Peanuts Grown in Gypsum-Supplemented Soil

1993 ◽  
Vol 56 (7) ◽  
pp. 593-594 ◽  
Author(s):  
CINDY L. C. REDING ◽  
MARK A. HARRISON ◽  
CRAIG K. KVIEN
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Fungal Biomass ◽  
Aspergillus Parasiticus ◽  
Calcium Supplementation ◽  
Fungal Growth ◽  
Growing Season ◽  
Aflatoxin Production ◽  
Layer Chromatography

Five levels of gypsum supplementation (0, 550, 1100, 2200, and 4400 kg ha−1) were applied to peanut fields 35 d after planting. After the growing season, peanuts were harvested, ground, and inoculated with 1 × 107 Aspergillus parasiticus (NRRL 5139) conidia. After 14 d at 25°C, aflatoxin was extracted and quantified by thin-layer chromatography. Fungal growth was assayed using a modified chitin assay. Peanuts from gypsum-supplemented fields at each level of supplementation supported significantly less aflatoxin production when compared to control peanuts (no calcium supplementation). Results from the chitin assay showed a decrease in fungal biomass which correlated with the decreased aflatoxin synthesis.

Simplified Qualitative Analysis of Glycerides Derived from Coconut Oil Using Thin Layer Chromatography

2012 ◽  
Vol 506 ◽  
pp. 182-185 ◽  
Author(s):  
Sirikarn Pengon ◽  
Chutima Limmatvapirat ◽  
Sontaya Limmatvapirat
Keyword(s):  
Acetic Acid ◽  
Qualitative Analysis ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Cocos Nucifera ◽  
Coconut Oil ◽  
Solvent System ◽  
Tlc Plates ◽  
Solvent Systems ◽  
Layer Chromatography

Coconut (Cocos nucifera L.) oil is composed predominately of medium-chain triglycerides which have been reported to be beneficial to human health. It also contains free fatty acids (FFAs) which can combine with glycerol to form monoglycerides, diglycerides, and triglycerides. The analysis of FFAs and their glycerides has been proposed to assess the quality of coconut oil used as raw materials in various industrial fields. The aim of this study was to develop the qualitative method for investigation of FFA and their glycerides in coconut oil using thin layer chromatography (TLC). Coconut oil and standards of FFA and their glycerides were chromatographed separately on Silica gel 60 F254 TLC plates using hexane: ether: acetic acid (60:40:1) and hexane: ethyl acetate: acetic acid (60:40:0.5) as solvent systems A and B, respectively. The spots on developing TLC plates were detected and compared using 254-nm UV light and iodine vapor. The results showed that the resolution of solvent system A was better than that of solvent system B. However, both solvent systems were used to confirm the results. The retention factor (Rf) values of the components were in good agreement with their polarity. This method should provide a guideline for qualitative analysis of coconut oil.

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