The MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] Assay Is a Fast and Reliable Method for Colorimetric Determination of Fungal Cell Densities

1999 ◽  
Vol 65 (8) ◽  
pp. 3727-3729 ◽  
Author(s):  
Florian M. Freimoser ◽  
Claude A. Jakob ◽  
Markus Aebi ◽  
Urs Tuor
Keyword(s):  
Colorimetric Method ◽  
Medium Composition ◽  
Colorimetric Determination ◽  
Fungal Cell ◽  
Diphenyltetrazolium Bromide ◽  
Hyphal Bodies ◽  
Growth Promoting ◽  
Cell Densities

ABSTRACT The entomopathogenic fungus Neozygites parvispora(Entomophthorales: Zygomycetes) grows in vitro as irregularly rod-shaped hyphal bodies in a complex medium. In order to simplify the medium composition and determine growth-promoting compounds for the cultivation of this fungus, we were looking for a rapid and quantitative method to estimate the number of living cells in small volumes of liquid culture. A colorimetric method for the determination of cell densities using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] proved to be more accurate and timesaving than conventional hemocytometer counting.

Colorimetric Determination of Hydroxyproline as Measure of Collagen Content in Meat and Meat Products: NMKL Collaborative Study

1990 ◽  
Vol 73 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Meat Products ◽  
Acid Oxidation ◽  
Colorimetric Determination ◽  
Mean Values ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Analytical Result

Abstract A colorimetric method for the determination of hydroxyproline as a measure of collagen in meat and meat products has been collaboratively studied in 18 laboratories. The method includes hydrolysis with sulfuric acid, oxidation with chloramine- T, and formation of a reddish purple complex with 4- dimethylaminobenzaldehyde. Five frozen and 3 freeze-dried samples were tested, ranging in content from 0.11 to 0.88% and from 0.39 to 4.0% hydroxyproline, respectively. The mean values of 2 identical samples were 0.245 and 0.251 %. The average recovery from a spiked sample was 96.1 %. The hydroxyproline content of a known sample (a mixture of 2 samples in the ratio 5:2) was calculated to 1.42%, which agrees well with the analytical result, 1.40%. In comparison with other collaborative studies, based on the ISO analytical method, the repeatability and reproducibility of this method agree well with the other results. This method was accepted as an official NMKL method by all national Committees, and has been adopted official first action by AOAC as an NMKLAOAC method.

200. The colorimetric determination of pH in milk and whey by means of the “Wulff” pH tester

1938 ◽  
Vol 9 (3) ◽  
pp. 336-338 ◽  
Author(s):  
E. Aschaffenburg
Keyword(s):  
Colorimetric Method ◽  
Cheddar Cheese ◽  
Titratable Acidity ◽  
Colorimetric Determination ◽  
Expensive Equipment ◽  
Hydrogenion Concentration ◽  
The Relationship

It has been repeatedly pointed out(1, 2, 3) that the properties of cheese during the different stages of its manufacture should be correlated with the hydrogenion concentration rather than with the titratable acidity. Little systematic work has, however, so far been carried out in this direction, except for a study of the relationship between pH and titratable acidity in Cheddar cheese by Brown & Price(4). In planning work on similar lines, it was realized that the potentiometric methods of determining pH require expensive equipment and skilled attention, so that a supplementary colorimetric method, if sufficiently accurate to indicate the major changes in pH, should appeal more strongly to the practical cheesemaker on account of its cheapness and simplicity and the ease with which the outfit can be transported.

Colorimetric Determination of Terbutaline Sulfate and Orciprenaline Sulfate via Nitrosation and Difference Spectrophotometry

1987 ◽  
Vol 70 (3) ◽  
pp. 568-571 ◽  
Author(s):  
Mohamed E El-Sadek ◽  
Hisham E Abdel Latef ◽  
Afaf A Aboul Khier
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Nitrite ◽  
Colorimetric Method ◽  
Dosage Forms ◽  
Alkaline Media ◽  
Colorimetric Determination ◽  
Pharmaceutical Dosage Forms ◽  
Terbutaline Sulfate ◽  
The Difference

Abstract A colorimetric method is proposed for determination of terbutaline sulfate, orciprenaline sulfate, and their dosage forms. The suggested method depends on nitrosation of the 2 drugs by using sodium nitrite and hydrochloric acid. Addition of sodium hydroxide increases the intensity of the color developed. The difference between absorption values measured in acid and alkaline media is taken as a measure of concentration. Variables were carefully studied and optimized. Results for both compounds adhered to Beer's law over the range 2- 28 μg/mL. The method has proved to be accurate and precise for analysis of pharmaceutical dosage forms.

Colorimetric determination of potassium in whole blood, serum, and plasma.

1985 ◽  
Vol 31 (9) ◽  
pp. 1464-1467 ◽  
Author(s):  
S T Wong ◽  
J Spoo ◽  
K C Kerst ◽  
T G Spring
Keyword(s):  
Whole Blood ◽  
Colorimetric Method ◽  
Direct Determination ◽  
Ion Pair ◽  
Photometric Method ◽  
Colorimetric Determination ◽  
Two Dimensional ◽  
Subsequent Formation ◽  
Blood Specimens

Abstract This spectrophotometric method for the direct determination of potassium in serum or plasma is based on the selective complexing of potassium by a specific macrocyclic polyether, with the subsequent formation of an ion-pair with a colored anion. The colored anion is extracted into an organic solvent, clarified by centrifugation, and then measured at 415 nm. The absorbance of the chromogen varies linearly with [K+] to at least 15 mmol/L. Results of this colorimetric method (y) correlate well with the results obtained by a flame-photometric method (y = 1.04x - 0.22, r = 0.97, n = 81), with CVs ranging from 2 to 4%. We observed no interferences from lipemia, added bilirubin, or various electrolytes. We also evaluated the use of this reagent in a new automated blood analyzer developed by Abbott, a two-dimensional centrifugal system (Clin Chem 31:1457-1463, 1985). Potassium determined with this system (y) correlated well with results by flame photometry: y = 1.02x + 0.02 (r = 0.94, n = 168). With this system one can use whole-blood specimens in measuring potassium.

Direct Colorimetric Determination of Hippuric Acid in Urine

1972 ◽  
Vol 18 (4) ◽  
pp. 349-351 ◽  
Author(s):  
Katsumaro Tomokuni ◽  
Masana Ogata
Keyword(s):  
Hippuric Acid ◽  
Colorimetric Method ◽  
Color Reaction ◽  
Colorimetric Determination ◽  
Benzenesulfonyl Chloride

Abstract A direct colorimetric method is described for determination of hippuric acid in urine. Hippuric acid dissolved in pyridine—water (1:1) produces a color (Amax = 410 nm) when benzenesulfonyl chloride is added. With the method based on this color reaction, urinary hippuric acid follows the Beer-Lambert law up to 1 mg/ml.

Colorimetric Determination of Dillapiole in Wheat

1979 ◽  
Vol 62 (1) ◽  
pp. 203-204
Author(s):  
Swadesh K Handa
Keyword(s):  
Sulfuric Acid ◽  
Colorimetric Method ◽  
Chromotropic Acid ◽  
Colorimetric Determination ◽  
Wheat Grain ◽  
Maximum Absorbance

Abstract A rapid colorimetric method has been developed for determining residues of dillapiole (3,4-methylenedioxy-5,6-dimethoxy allyl benzene) in wheat grain. Dillapiole is reacted with sulfuric acid to liberate formaldehyde which reacts with chromotropic acid to yield a pink compound with maximum absorbance at 575 nm. The method can detect 1—15 μg residue /ml.

Colorimetric Determination of Certain Phenothiazine Drugs by Using Morpholine and Iodine-Potassium Iodide Reagents

1986 ◽  
Vol 69 (3) ◽  
pp. 513-518 ◽  
Author(s):  
Adel F Youssef ◽  
Salwa R El-Shabouri ◽  
Fardous A Mohamed ◽  
Abdel Maboud I Rageh
Keyword(s):  
Potassium Iodide ◽  
Quantitative Estimation ◽  
Colorimetric Method ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Colorimetric Determination ◽  
Reaction Products ◽  
Phenothiazine Drugs ◽  
Lower Molar

Abstract A colorimetric method was developed for the quantitative estimation of 11 phenothiazine drugs. The method is based on the interaction of unsulfoxidized drug with morpholine and iodine-potassium iodide reagents. The interaction for all studied phenothiazine drugs yields a blue product with 2 absorption maxima: one in the range of 620-640 nm with lower molar absorptivity and the other in the range of 662-690 nm with higher molar absorptivity. The color was stable for at least 10 h. The reproducibility and recovery of the method were excellent. The method was applied successfully to the analysis of various commercially available phenothiazines in different dosage forms. The results were comparable to those obtained by official procedures. The suitability of the method for detection and estimation of promethazine excreted in urine has been suggested by preliminary experiments. Reaction products have been isolated and identified.

Colorimetric determination of carboxypeptidase A activity in serum.

1986 ◽  
Vol 32 (5) ◽  
pp. 748-751 ◽  
Author(s):  
H Saruta ◽  
Y Ashihara ◽  
M Sugiyama ◽  
M Roth ◽  
E Miyagawa ◽  
...  
Keyword(s):  
Oxidative Coupling ◽  
Sodium Periodate ◽  
Colorimetric Method ◽  
Hydroxybenzoic Acid ◽  
Colorimetric Determination ◽  
Carboxypeptidase A ◽  
Elastase 1 ◽  
Optimum Ph ◽  
Immunoreactive Elastase

Abstract This simple, reproducible colorimetric method for determining the activity of carboxypeptidase A (EC 3.4.17.1) is based on measuring the absorbance at 505 nm of a quinoneimine dye produced from the action of this enzyme on the new substrate p-hydroxybenzoyl-glycyl-L-phenylalanine. The enzyme acts on the substrate to produce p-hydroxybenzoyl-glycine and L-phenylalanine. The former is then hydrolyzed by hippuricase (EC 3.5.1.14) to produce p-hydroxybenzoic acid and glycine. Finally, oxidative coupling of p-hydroxybenzoic acid with 4-aminoantipyrine by sodium periodate forms a quinoneimine dye. The Km for the reaction with this substrate is 3.6 mmol/L; the optimum pH is 7.8. Our within-run and between-run CVs are 4.3% and 6.6%, respectively. The activity of carboxypeptidase A in serum correlates well with that of lipase (r = 0.96) and immunoreactive elastase-1 (r = 0.76).

scholarly journals A novel sensitive colorimetric determination of catecholamine drug in dosage form via oxidative coupling reaction with MBTH and potassium ferricyanide

2021 ◽  
Vol 5 (1) ◽  
pp. 51-58
Author(s):  
Safwan Ashour
Keyword(s):  
Oxidative Coupling ◽  
Colorimetric Method ◽  
Standard Free Energy ◽  
Coupling Reaction ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Potassium Ferricyanide ◽  
Colorimetric Determination ◽  
Oxidative Coupling Reaction

A new and direct colorimetric method has been established for the determination of catecholamine (methyldopa, MD) in both pure form and in pharmaceutical formulations. The method is based on the oxidative coupling reaction of MD with 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH) and potassium ferricyanide at pH 10.4 in aqueous medium to form an orange product that has a maximum absorption at 460 nm. Beer's law plot showed good correlation in the concentration range of 1.0−56.0 µg mL-1, with detection limit of 0.31 µg mL-1. Molar absorptivity for the above method was found to be 6.56×103 L mol-1 cm-1. All the measurements were carried out at 25 ± 1.0 °C, the formation constant (logKf) value of colored species is 9.48 and the standard free energy (DG‡) is − 54.09 KJ mol-1. This method was applied successfully to determination of MD in tablets and the results were compared with the USP method. Common excipients used as additives in tablets do not interfere in the proposed method. The method is accurate, precise and highly reproducible, while being simple, cheap and less time consuming and hence can be suitably applied for routine analysis of MD in bulk and dosage forms.

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