Assay of L( + )-Ascorbic Acid in Buttermilk by Densitometric Transmittance Measurement of the Dehydroascorbic Acid Osazone

1974 ◽  
Vol 57 (1) ◽  
pp. 65-69
Author(s):  
Paul R Beljaars ◽  
Wouter Van Steenbergen Horrocks ◽  
Theo M M Rondags
Keyword(s):  
Ascorbic Acid ◽  
Acetic Acid ◽  
Quantitative Analysis ◽  
Thin Layer ◽  
Coefficient Of Variation ◽  
Dehydroascorbic Acid ◽  
Tlc Plates ◽  
The Relationship ◽  
Layer Chromatography ◽  
Flying Spot

Abstract A study is presented for the quantitative analysis of ascorbic acid in buttermilk samples, using densitometric transmittance measurements. The procedure is based on oxidation of ascorbic acid to dehydroascorbic acid, followed by reaction with 2,4-dinitrophenylhydrazine to form the dinitrosazone. The osazone is separated from interfering substances in the sample by thin layer chromatography (TLC) on silica gel G plates developed with chloroform-ethyl acetate-acetic acid (60+35+5) . The TLC plates are scanned with a flying-spot densitometer. The relationship between integrated signal and concentration is linear for 0.08—1.00 fig ascorbic acid (coefficient of variation 3—4%). Deviations from Beer's law start to appear at levels higher than 1.00 fig ascorbic acid. A mean coefficient of variation of 3.5±1.1% (P = 95%) was established for standard spot measurements (3 spots averaged) on 15 chromatoplates. Recovery of ascorbic acid added to buttermik was 98% (coefficient of variation 7.2%). Results of this study are compared with those reported for spectrophotometric, titrimetric, and potentiometric procedures. The proposed method is less accurate because of interferences and the subsequent variables which arise as a result of taking transmittance measurements through an opaque medium.

Notizen: Improved 2,4-Dinitrophenylhydrazine, Thin Layer Chromatography Methods for the Determination of Micro- and Macroamounts of Ascorbic Acid

1974 ◽  
Vol 29 (11-12) ◽  
pp. 777-780 ◽  
Author(s):  
A. Navon ◽  
H. Z. Levinson
Keyword(s):  
Acetic Acid ◽  
Vitamin C ◽  
Thin Layer ◽  
Condensation Reaction ◽  
Dehydroascorbic Acid ◽  
Previous Method ◽  
Aqueous Acetic Acid ◽  
Tlc Plates ◽  
Layer Chromatography

Microamounts of vitamin C could be readily determined in 20 μl-samples using the 2,4-dinitrophenylhydrazine method together with separation by thin layer chromato­graphy. The condensation reaction was carried out for 5 min at 100 °C on a glass fibre disc. Purification of vitamin C hydrazones was accomplished by repeated separation on TLC plates. An aqueous solution of 65% acetic acid was em­ployed to dissolve the vitamin C hydrazones, providing maxi­mal absorbance at 500 nm. The minimum amount detectable by this method is 0.4 μg of dehydroascorbic acid. The macrodetermination of vitamin C was improved by simpli­fying a previous method and employing 65% aqueous acetic acid as a solvent for the hydrazones.

Quantitative Fluorodensitometric Determination and Survey of Aflatoxins in Nutmeg

1975 ◽  
Vol 58 (2) ◽  
pp. 263-271
Author(s):  
Paul E Beljaars ◽  
Jan C H M Schumans ◽  
Paul J Koken
Keyword(s):  
Thin Layer ◽  
Coefficient Of Variation ◽  
Analytical Procedure ◽  
Confirmatory Test ◽  
Average Recovery ◽  
Different Types ◽  
Tlc Plates ◽  
Aoac Official ◽  
Layer Chromatography ◽  
Flying Spot

Abstract A study is presented for the quantitative fluorodensitometric analysis of aflatoxins in spices, in particular nutmeg (Semen myristicae). Samples were extracted with chloroform, followed by silica gel column cleanup according to the AOAC official first action method, 26.019(a), and by 2-dimensional thin layer chromatography according to the antidiagonal technique. The method includes a confirmatory test for aflatoxins by hemiacetal formation. The concentrations of aflatoxins in samples were determined by measurement of the fluorescent intensities of the separated aflatoxin spots from sample and standards on the same chromatoplate with a reflectance flying-spot densitometer. With such a technique, a coefficient of variation value of 5.22±1.24% (P < 99%) was calculated for a series of 5 standard B, spots and averaged for 13 TLC plates, demonstrating the precision of the chromatographic and densitometric procedures. An average recovery of 108.4±5.8% (P < 95%) was obtained for 11 spiked nutmeg extracts (5.0–20.0 μg B1 added/kg), whereas an average recovery of 92.6±4.9 (P < 95%) was established for 13 spiked nutmeg samples (5.0–20.0 μg B1 added/kg). The coefficient of variation of the complete analytical procedure for ground nutmeg was 8.80%. In a survey on the occurrence of aflatoxins in 40 commercial nutmeg samples (covering 12 different brands) in The Netherlands, aflatoxins were detected in 30 ground samples (32 ground samples analyzed) in concentrations ranging from 1.0 to 23.2 μg B1/kg or from 2.7 to 36.5 μg B1 + B2 + G1 + G2/kg, whereas no aflatoxins were present in whole nutmeg kernels (8 samples analyzed). The lowest level of detection was 1.0 μB1/kg. In addition, 50 commercial spices consisting of 19 different types of commodities other than nutmeg were assayed for aflatoxins according to the same procedure. No aflatoxins were detected in these samples, with the exception of 1 sample of bay leaf which contained 5.1 μg B1/kg.

Thin Layer Chromatographic Determination of Citrinin

1979 ◽  
Vol 62 (1) ◽  
pp. 201-202 ◽  
Author(s):  
Robert D Stubblefield
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Linear Relationship ◽  
Silica Gel ◽  
Coefficient Of Variation ◽  
Ethylenediaminetetraacetic Acid ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Tlc Plates

Abstract Clearly defined zones of citrinin can be obtained on thin layer chromatographic (TLC) plates and measured by fluorodensitometry. Silica gel plates were prepared as a slurry with aqueous 0.05M Na2EDTA (ethylenediaminetetraacetic acid), spread at 0.5 mm wet thickness, and activated at 105°C for 1 hr. Plates were developed in acetic acid-benzene (5+95). The limit of detection was 10 ng citrinin/zone. Densitometric analysis (365 nm excitation, 505 nm emission) revealed that a linear relationship exists for levels of 10 ng to at least 100 ng/zone wtih a coefficient of variation of ±5%.

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.

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.

scholarly journals DEVELOPMENT OF QUALITY CONTROL PARAMETERS FOR STANDARDIZATION OF A NOVELMUCILAGE OBTAINED FROM OKRA (ABELMOSCHUS ESCULENTUS (L.) MOENCH) FRUIT

2021 ◽  
pp. 28-41
Author(s):  
SOMA DAS ◽  
ANANYA GHOSH ◽  
RUSHAM DAS ◽  
GOURANGA NANDI ◽  
LAKSHMI KANTA GHOSH
Keyword(s):  
Quality Control ◽  
Ascorbic Acid ◽  
Quantitative Analysis ◽  
Amino Acid ◽  
Thin Layer ◽  
High Performance ◽  
Control Parameters ◽  
Fruit Extract ◽  
Quality Control Parameters ◽  
Layer Chromatography

Objective: The main objective was to focus on qualitative and quantitative analysis of isolated okra mucilage by High-performance Thin Layer Chromatography to set up the quality control parameters for the isolated mucilage. Methods: High-performance thin-layer chromatography (HPTLC) were applied for the identification of components present in methanolic and ethanolic fruit extract of okra at 254 nm and 356 nm. Quantitative analysis of amino acid ascorbic acid and total polyphenol content was determined. Results: The results showed that the yield percentage for methanolic and ethanolic fruit extract of the okra fruit mucilage was found to be 13.5 and12.5% respectively. HPTLC determination of methanolic and ethanolic okra fruit extract showed the presence of 8 components with Rf values in the range of 0.14 to 0.62 and 0.14 to 0.54 respectively when detected at wavelengths 254 nm and at 356 nm. The total amino acid in okra fruit methanolic extract was found to be 11.45%w/w. The ascorbic acid content in methanolic okra fruit extract and ethanolic okra fruit extract was found to be 0.24 %w/w and 0.18% w/w respectively. The total phenolic contents (tannic acid equivalents, mg/g) in the methanolic and ethanolic okra fruit extracts were calculated to be 4.6 % w/wand 5.3% w/w respectively. Conclusion: The data revealed dual benefits like it can act as a potential novel functional ingredient with health-promoting application due to the presence of ascorbic acid and total phenolics contents and at the same time the data provided guidelines for quality control parameters for the isolated okra fruit

Separation of dl-2-(3-Phenoxyphenyl) propionic Acid (Fenoprofen) From Its Intermediates by Thin Layer Chromatography

1973 ◽  
Vol 56 (3) ◽  
pp. 656-658
Author(s):  
Rafik H Bishara
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Lower Limit ◽  
Raw Material ◽  
Chemical Constitution ◽  
Tlc Plates ◽  
Rf Values ◽  
Synthetic Intermediates ◽  
Layer Chromatography

Abstract Fenoprofen and its synthetic intermediates are resolved on silica gel F254 TLC plates developed with chloroform-acetic acid (98+2). The interrelationship between the chemical constitution and the Rf values is discussed. The lower limit of detecting the intermediates in Fenoprofen raw material is 1%.

Observations on the use of 2,4-dinitrophenylhydrazine and of 2,6-dichlorophenolindophenol for the determination of vitamin C in raw and in heat-treated milk

1970 ◽  
Vol 37 (1) ◽  
pp. 29-45 ◽  
Author(s):  
Joyce Toothill ◽  
S. Y. Thompson ◽  
J. Edwards-Webb
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Ascorbic Acid ◽  
Vitamin C ◽  
Thin Layer ◽  
Dehydroascorbic Acid ◽  
Heat Treated ◽  
Sterilized Milk ◽  
Layer Chromatography

SummaryA study has been made of methods using 2,4-dinitrophenylhydrazine (DNPH) or 2,6-dichlorophenolindophenol (DCP) for the determination of vitamin C (ascorbic acid+dehydroascorbic acid) in raw, UHT processed, evaporated and sterilized milk.Interfering substances were not detected in milk that had received a heat treatment no more severe than 145°C for 4 s (UHT process), so that either reagent could be used.With more drastic heat treatment, interfering substances were formed and only the DNPH method with column and thin layer chromatography of the DNPH derivatives was specific for vitamin C. With in-bottle sterilized milk, the values for ascorbic acid were (in mg/100 ml) 1·16 (DCP method with H2S reduction); 0·58 (DCP method with Escherichia coli reduction); 0·64 (DNPH method); 0·33 (DNPH method combined with chromatography).In our experience the DNPH method combined with chromatography of the derivatives is highly specific for vitamin C and should be used to check the results obtained by other and simpler methods.

Chromatographic and Extraction Techniques for Vitamin C Assay

1965 ◽  
Vol 48 (5) ◽  
pp. 985-991
Author(s):  
Elmer De Ritter
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Thin Layer ◽  
Dehydroascorbic Acid ◽  
Reduced Form ◽  
Extraction Techniques ◽  
Total Vitamin ◽  
High Efficient ◽  
Efficient Extraction ◽  
Layer Chromatography

Abstract A review is presented of chromatographic procedures used in the assay of vitamin C. Paper, thin layer, and column chromatography have been used to advantage for separating interfering substances. Even the closely related erythorbic acid, which has no vitamin C activity, can be separated from ascorbic acid by various techniques on paper. Total vitamin C can be determined chromatographically after reduction of dehydroascorbic acid with H2S or after oxidation of the reduced form to dehydroascorbic acid. A combination of column and thin layer chromatography on silica gel of the dinitrosazone formed by reaction of dehydroascorbic acid with 2,4-dinitrophenylhydraiine is recommended as an effective method for achieving specificity in vitamin C assays of foods and feeds where the level of interference is high. Efficient extraction procedures are described for determining added ascorbic acid in feeds and mineral premixes.

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