Analysis of Ochratoxins A and B and Their Esters in Barley, Using Partition and Thin Layer Chromatography. I. Development of the Method

1973 ◽  
Vol 56 (4) ◽  
pp. 817-821 ◽  
Author(s):  
Stanley Nesheim ◽  
Nicole F Hardin ◽  
Octave J Francis ◽  
William S Langham
Keyword(s):  
Sodium Bicarbonate ◽  
Diatomaceous Earth ◽  
Average Recovery ◽  
Aqueous Sodium ◽  
Lower Detection Limit ◽  
Aqueous Sodium Bicarbonate ◽  
Lower Detection ◽  
Tlc Plates ◽  
Layer Chromatography

Abstract A convenient, specific, rapid method, developed for the determination of ochratoxin in barley, involves initial extraction of the sample with water-chloroform (1+9), followed by chromatography of the extract on an aqueous sodium bicarbonate-diatomaceous earth column. The ochratoxin esters are removed from the column with hexane-chloroform. Elution of the column with formic acid-chloroform (1+99) yields ochratoxins A and B. The ochratoxin esters are purified further on an aqueous sodium bicarbonate-methanol-diatomaceous earth column. The extracts are then quantitated on TLC plates by measuring fluorescence intensity. The presence of ochratoxins A and B is confirmed through formation of the corresponding ethyl ester derivatives. In an intralaboratory study, in which samples spiked at 25, 50, and 100 μg/kg levels were analyzed by 4 analysts, the average recovery for ochratoxin A was 81.2% with a lower detection limit of 12 μg/kg.

Determination of Cyclopiazonic Acid in Peanuts and Corn by Thin Layer Chromatography

1986 ◽  
Vol 69 (6) ◽  
pp. 964-966 ◽  
Author(s):  
John A Lansden
Keyword(s):  
Detection Limit ◽  
Sodium Bicarbonate ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Cyclopiazonic Acid ◽  
Chromatographic System ◽  
Aqueous Sodium ◽  
Absolute Detection Limit ◽  
Layer Chromatography

Abstract A thin layer chromatographic system including densitometry has been developed for determining cyclopiazonic acid in peanuts and corn. Samples are extracted with methanol-chloroform (20 + 80); the extract is stripped of most interferences by partitioning with aqueous sodium bicarbonate followed by acidification and repartitioning with chloroform. After thin layer chromatography and derivatization with dimethylaminobenzaldehyde- HCl spray, the toxin is quantitated by reflection densitometry at 540 nm. The recovery of cyclopiazonic acid averages 90% for peanuts and 85% for corn. The absolute detection limit is 25 ng per spot which translates to a detection limit of 125 μg/kg for a 50 g sample.

Comprehensive study of the toothpaste containing fluoride and 67% aqueous sodium bicarbonate solution

2021 ◽  
Vol 26 (2) ◽  
pp. 137-143
Author(s):  
S. N. Gromova ◽  
N. A. Guzhavina ◽  
E. A. Falaleeva ◽  
E. P. Kolevatykh ◽  
А. V. Elikov ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
Oral Care ◽  
Sodium Bicarbonate Solution ◽  
Comprehensive Treatment ◽  
Aqueous Sodium ◽  
Aqueous Sodium Bicarbonate ◽  
Periodontal Inflammation ◽  
Aqueous Sodium Bicarbonate Solution ◽  
Inflammatory Effect

Relevance. A wide variety of oral care products is available nowadays. Sometimes aggressive advertising rather than doctor’s advice determines our patients’ choice. In our research, we provide evidence of the clinical use of toothpaste containing fluoride and sodium bicarbonate.Materials and methods. During four weeks, we followed up a group of students who used the toothpaste containing 1400 ppm fluoride and 67% aqueous sodium bicarbonate solution. The clinical, biochemical and microbiological tests and saliva crystallization score assessed the characteristics stated by the manufacturer.Results. The statistically significant correlation between all studied criteria is evidence of the effectiveness of the toothpaste. In addition to the significant remineralization and antiplaque effect, biochemical and microbiological tests confirmed the anti-inflammatory effect of the toothpaste. An immediate cleaning effect was observed after the first brushing as well as in long-term use.Conclusion. Improvement of oral hygiene indices and reduction of periodontal inflammation confirmed the successful result of the comprehensive treatment of chronic gingivitis.

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.

Improved Spectrophotometric Determination of Cyclopiazonic Acid in Poultry Feed and Corn

1990 ◽  
Vol 73 (2) ◽  
pp. 257-259 ◽  
Author(s):  
Ivan Chang-Yen ◽  
Keshore Bidasee
Keyword(s):  
Detection Limit ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Cyclopiazonic Acid ◽  
Poultry Feed ◽  
Reaction Conditions ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Feed Samples

Abstract An improved visible spectrophotometric method has been developed for cyclopiazonic acid in poultry feed and corn. The method Is based on the reaction of cyclopiazonic acid with Ehrlich reagent and detection at 580 nm. Reaction conditions were optimized with respect to reaction and measurement times and acid and Ehrlich reagent concentrations. Calibration curves were linear from 1 to 20 μg cyclopiazonic acid in 3 mL Ehrlich reagent, with a lower detection limit of 0.08 mg/kg for 50 g samples of poultry feed and corn. Recoveries from 50 g samples of poultry feed spiked with cyclopiazonic ranging from 0.16 to 1.20 mg/kg averaged 93.8%. Moldy corn and poultry feed samples analyzed by this method contained between 1 and 4 mg/kg cyclopiazonic acid.

Determination of Citrinin in Corn and Barley on Thin Layer Chromatographic Plates Impregnated with Glycolic Acid

1984 ◽  
Vol 67 (1) ◽  
pp. 194-196
Author(s):  
Alberto Gimeno
Keyword(s):  
Thin Layer ◽  
Glycolic Acid ◽  
Detection Method ◽  
Minimum Detectable Concentration ◽  
Extraction Solvent ◽  
Detectable Concentration ◽  
Tlc Plates ◽  
Limit Detection ◽  
Layer Chromatography

Abstract A method is described for the determination of citrinin in corn and barley. The mycotoxin is extracted with a mixture of acetonitrile-10% glycolic acid in water, defatted with isooctane, and transferred to chloroform according to published methods. The mycotoxin is separated by thin layer chromatography (TLC) on plates previously impregnated with 10% glycolic acid solution in ethanol; identity is confirmed by chemical tests. Citrinin is then quantitated by the limit detection method. Recoveries of citrinin from corn and barley samples spiked at levels of 50, 80, 150, 300, 500, and 1000 μg/kg were in the range 91-98%. The minimum detectable concentration is 15-20 μg/ kg. Recoveries obtained with and without glycolic acid in the extraction solvent were compared. Sensitivities on TLC plates (limits of detection, μg/spot) impregnated with glycolic acid were compared with those on plates impregnated with oxalic acid.

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.

scholarly journals Determination of epinephrine by the Briggs-Rauscher oscillating system using non-equilibrium stationary state

2012 ◽  
Vol 77 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Jinzhang Gao ◽  
Yanjun Liu ◽  
Jie Ren ◽  
Xiaoli Zhang ◽  
Li Ming ◽  
...  
Keyword(s):  
Detection Limit ◽  
Stationary State ◽  
Lower Detection Limit ◽  
Highly Sensitive ◽  
Lower Detection ◽  
Oscillating Reaction ◽  
The Difference ◽  
Foreign Species ◽  
Non Equilibrium

A highly sensitive method for the determination of epinephrine was proposed, which was based on the perturbation of epinephrine to Briggs-Rauscher oscillating system involving malonic acid, Mn2+, H+, IO3 - and H2O2 at non-equilibrium stationary state. The concentration of KIO3 was chosen as a control parameter to find the bifurcation point in this paper. Results showed that a well linear relationship between the difference of potential and the negative logarithm concentrations of epinephrine existed in the range of 1.1?10-7?5.2?10-9 mol L-1 with a lower detection limit of 6.8?10-10mol L-1 and a correlation coefficient of 0.9974. Compared to the classical oscillating reaction, this method has a lower detection limit and wider linear range. The effects of some foreign species, which may possibly be existed with epinephrine, on determination were also investigated. The proposed method has been successfully used to determine the epinephrine both in the serum and adrenaline hydrochloride injection.

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