A MODIFIED METHOD FOR THE COLORIMETRIC DETERMINATION OF HEPARIN

1967 ◽  
Vol 45 (5) ◽  
pp. 787-794 ◽  
Author(s):  
L. B. Jaques ◽  
A. Wollin
Keyword(s):  
Colorimetric Assay ◽  
Colorimetric Determination ◽  
Azure A ◽  
Modified Method

A sensitive accurate quantitative colorimetric assay for heparin with Azure A using the Beckman DK-2 spectrophotometer is described. Limits for the presence of impurities and precautions are given.

Rapid Colorimetric Assay of Trimethoprim and Sulfamethoxazole in Pharmaceuticals

1983 ◽  
Vol 66 (6) ◽  
pp. 1447-1449 ◽  
Author(s):  
Asis K Sanyal ◽  
Dinabandhu Laha
Keyword(s):  
Solvent Extraction ◽  
Colorimetric Assay ◽  
Pharmaceutical Preparations ◽  
Ion Pair ◽  
Pair Formation ◽  
Bromophenol Blue ◽  
Colorimetric Determination ◽  
Ion Pair Formation ◽  
Subsequent Measurement

Abstract A method is described for the direct colorimetric determination of trimethoprim and sulfamethoxazole in pharmaceutical preparations, without prior separation. Estimation of trimethoprim is based on its ion-pair formation with bromophenol blue and subsequent measurement of absorbance of the ionpair at 418 nm. Estimation of sulfamethoxazole is possible without removal of trimethoprim by solvent extraction.

Convenient and sensitive colorimetric determination of alendronate sodium with Ce4+-triggered oxidation of TMB

2020 ◽  
Vol 44 (30) ◽  
pp. 12962-12966
Author(s):  
Jing Sun ◽  
Rui Wang ◽  
Meng Xia ◽  
Shuyun Zhu ◽  
Xian-En Zhao
Keyword(s):  
Colorimetric Assay ◽  
Colorimetric Determination ◽  
Selective Detection ◽  
Alendronate Sodium ◽  
First Time

A facile colorimetric assay for the sensitive and selective detection of alendronate sodium has been developed based on Ce4+-triggered oxidation of TMB for the first time.

Colorimetric Determination of Potassium in Plasma and Serum by Reflectance Photometry with a Dry-Chemistry Reagent

1992 ◽  
Vol 38 (7) ◽  
pp. 1371-1372 ◽  
Author(s):  
R H Ng ◽  
K M Sparks ◽  
B E Statland
Keyword(s):  
Reference Material ◽  
Standard Reference Material ◽  
Colorimetric Assay ◽  
Ion Selective Electrode ◽  
Colorimetric Determination ◽  
Selective Electrode ◽  
Flame Photometer ◽  
Near Patient Testing

Abstract We evaluated a colorimetric assay of potassium in plasma and serum with the Boehringer Mannheim Reflotron reflectance photometric analyzer, which is designed for near-patient testing in hospitals and physicians' offices. This potassium method does not require calibration or instrument maintenance by the operator. Analysis of 30 microL of plasma or serum takes approximately 140 s. Within-day imprecision (CV) was 1.0-1.2%. Total CVs over a 1-month period were 1.0-1.4%. Patients' results from the Reflotron correlated well with those from the IL 643 flame photometer and the Beckman Synchron CX3 ion-selective electrode methods. The accuracy of Reflotron values was also verified with Standard Reference Material 956 from the National Institute of Standards and Technology.

Colorimetric Determination of Serum Isocitric Dehydrogenase

1960 ◽  
Vol 6 (3) ◽  
pp. 208-215 ◽  
Author(s):  
Thomas H Taylor ◽  
Michael E Friedman
Keyword(s):  
Colorimetric Assay ◽  
Colorimetric Determination ◽  
Reaction Products ◽  
Standard Unit ◽  
Isocitric Dehydrogenase

Abstract A colorimetric assay of serum isocitric dehydrogenase has been described in which the α-ketoglutaric acid formed is determined as the hydrazone. A standard unit of lCD activity is defined as millimicromoles KG-A formed per milliliter serum per hour of incubation at 37°. Analyses of KGA and TPNH as reaction products show that 1.58 moles of KGA are formed for each mole of TPNH under the conditions of this experiment.

Analyses of Fat-Soluble Vitamins, XIV. Collaborative Study of the Determination of Vitamin D in Multivitamin Preparations

1977 ◽  
Vol 60 (1) ◽  
pp. 151-154
Author(s):  
Frits J Mulder ◽  
Ellen J De Vries ◽  
Ben Borsje
Keyword(s):  
Vitamin D ◽  
Polyethylene Glycol ◽  
Vitamin A ◽  
Colorimetric Assay ◽  
Collaborative Study ◽  
Official Method ◽  
Colorimetric Determination ◽  
Trans Isomers ◽  
Decomposition Products

Abstract The colorimetric assay for the determination of vitamin D (4000—50,000 international units (IU)/g) in multivitamin preparations has been collaboratively studied. The method is based on the same principle as the official method for the determination of vitamin D in concentrates, i.e., elimination of trans-isomers of vitamin D resins. The method includes the following steps: saponification and extraction (isolation of unsaponifiable material), phosphate-treated alumina column chromatography (elimination of tocopherols and vitamin A decomposition products), partition chromatography with polyethylene glycol 600 and Celite (separation of vitamin D fraction from vitamin A alcohol), adsorption chromatography on Florex (elimination of vitamin A decomposition products and small amounts of polyethylene glycol 600), maleic anhydride addition reaction (elimination of trans-isomers of vitamin D resins), and colorimetric determination at 2 wavelengths with and without acetic anhydride (an inhibitor for the color reaction of vitamin D and antimony trichloride). The mean result of 4 laboratories for 8 different samples, expressed as per cent of the known amount of vitamin D added, was 95.8% with a coefficient of variation of 10.5%. Considering the complexity of the method, the collaborative results were reasonable. The method has been adopted as official first action.

Comparison of Two Methods and Improvements for Colorimetric Determination of Nitrite in Cod Roe

1979 ◽  
Vol 42 (9) ◽  
pp. 715-718 ◽  
Author(s):  
YOSHIO ITO ◽  
MICHIYO YODOSHI ◽  
JUN-ICHI TANAKA ◽  
MASAHIRO IWAIDA
Keyword(s):  
Meat Products ◽  
Reference Method ◽  
Coupling Reaction ◽  
Original Method ◽  
Colorimetric Determination ◽  
Modified Method ◽  
Color Development ◽  
Reproducible Method ◽  
Ppm Level

Attempts were made to develop a sensitive and reproducible method to determine nitrite in cod roe. Two diazotation-coupling reaction methods were considered; (a) the method defined by the Ministry of Health and Welfare of Japan (Method 1) and (b) the reference method of ISO (Method 2). Since the nitrite content in cod roe was much less than in meat products, Method 2 was modified to make it suitable for microanalysis at 1 ppm level as NO2. Modifications included reducing volumes of color-development solutions and making changes in the color development process, thus making the color intensity four times as great as before. Carrying out corrections with both reagent and water blanks made the effect of the blank on measured values negligible. Recoveries of nitrite at 20- and 2-ppm levels were 94.7 and 88.1%, respectively, reproducibility being ± 7 .9%, as the coefficient of variation. The obtained values by the modified method were, on the average, higher than those of the original method by 37.1%. Nitrite contents obtained by Method 1 were lower than those by the original Method 2. These low values might be attributed to loss of nitrite during extraction from the sample without pH adjustment, since the measured value showed a remarkable increase by addition of alkaline solution before extraction. Nitrite contents in imported cod roe were within the range 0.16–1.03 ppm expressed as NO2.

Colorimetric Determination of 2,6-Dichloro-4-Nitroaniline (Dichloran) Residues in Foods

1969 ◽  
Vol 52 (4) ◽  
pp. 797-799
Author(s):  
James A Heagy
Keyword(s):  
Colorimetric Method ◽  
Chromatographic Column ◽  
Colorimetric Determination ◽  
Modified Method ◽  
Color Development ◽  
Development Procedure

Abstract The colorimetric method of Groves and Chough for determining dichloran residues in food was modified. The modified method uses a Florisil chromatographic column cleanup and a Bratton-Marshall color development procedure. Recoveries ranged from 90 to 100% for eight crops. The method is recommended for further study.

Rapid Colorimetric Assay for Nitroglycerin, Suitable for Content Uniformity Testing

1970 ◽  
Vol 53 (3) ◽  
pp. 579-581
Author(s):  
Clyde E Wells ◽  
Harvey M Miller ◽  
Yvonne H Pfabe
Keyword(s):  
Standard Deviation ◽  
Colorimetric Assay ◽  
Content Uniformity ◽  
Colorimetric Determination ◽  
Isolation Method ◽  
Infrared Method ◽  
Content Uniformity Testing ◽  
Chromatographic Isolation ◽  
Column Chromatographic

Abstract The column chromatographic isolation method of Hohmann and Levine has been combined with a modified version of the colorimetric determination of Bell, resulting in a convenient assay for nitroglycerin in tablets. The method agrees closely with the AOAC infrared method and is sensitive enough for analysis of individual tablets (0.15 mg nitroglycerin). The standard deviation is 0.91% at the 1.2 mg level.

scholarly journals Colorimetric Determination of Hypochlorite Based on the Oxidative Leaching of Gold Nanorods

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1629 ◽  
Author(s):  
Yurong Ma ◽  
Yingyi Zhu ◽  
Benzhi Liu ◽  
Guixiang Quan ◽  
Liqiang Cui
Keyword(s):  
Gold Nanorods ◽  
Color Change ◽  
Colorimetric Assay ◽  
Tap Water ◽  
Critical Role ◽  
Colorimetric Method ◽  
Residual Chlorine ◽  
Colorimetric Determination ◽  
Oxidative Leaching

Hypochlorite plays a critical role in killing microorganisms in the water. However, it can also cause cardiovascular diseases, neuron degeneration, and cancer to humans. Although traditional methods feature excellent sensitivity and reliability in detecting hypochlorite, the expensive instruments and strict determination conditions have limited their application in environmental analysis to some extent. Thus, it is necessary and urgent to propose a cheap, facile, and quick analytical assay for hypochlorite. This paper proposes a colorimetric assay for hypochlorite utilizing gold nanorods (AuNRs) as the nanoreactor and color reader. The AuNRs were acquired via a reported seed-mediated method. NaClO with strong oxidation property can cause the etching of gold from the longitudinal tips of AuNRs, which could shorten the aspect ratio of AuNRs, decrease the absorption in the UV–Vis spectrum and also induce the solution color changing from red to pale yellow. Thus, according to the solution color change and the absorbance of longitudinal surface plasmon resonance of AuNRs, we established the calibration curve of NaClO within 0.08 μM to 125 μM (∆Abs = 0.0547 + 0.004 CNaClO, R2 = 0.9631). Compared to traditional method, we obtained the conversion formula between the concentration of residual-chlorine in tap water and the concentration of hypochlorite detected by the proposed colorimetric assay, which is Cresidual-chlorine = 0.24 CNaClO. Finally, the real application of the colorimetric assay in tap water was successfully performed, and the accuracy of the colorimetric method can reach from −6.78% to +8.53%.

Suggested Modified Method for Colorimetric Determination of Selenium in Natural Water

1960 ◽  
Vol 52 (9) ◽  
pp. 1199-1205 ◽  
Author(s):  
George B. Magin ◽  
Leland L. Thatcher ◽  
Shirley Rettig ◽  
Harry Levine
Keyword(s):  
Natural Water ◽  
Colorimetric Determination ◽  
Modified Method
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