A time-insensitive colorimetric sensor for the determination of total protein

In this study, tannic acid-modified gold nanoparticles were found to have superior nanozyme activity and catalyze the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine in the presence of hydrogen peroxide. Enhancing the catalytic activity of the nanozyme by Pb2+ ions caused by selectively binding metal ions by the tannic acid-capped surface of gold nanoparticles makes them an ideal colorimetric probe for Pb2+. The parameters of the reaction, including pH, incubation time, and concentration of components, were optimized to reach maximal sensitivity of Pb2+ detection. The absorption change is directly proportional to the Pb2+ concentration and allows the determination of Pb2+ ions within 10 min. The colorimetric sensor is characterized by a wide linear range from 25 to 500 ng×mL−1 with a low limit of detection of 11.3 ng×mL−1. The highly sensitive and selective Pb2+ detection in tap, drinking, and spring water revealed the feasibility and applicability of the developed colorimetric sensor.

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Methodological features of the spectrophotometric determination of proteins in biological fluids using reactions with brompyrogallol red

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2020-86-2-15-22 ◽

2020 ◽

Vol 86 (2) ◽

pp. 15-22

Author(s):

T. B. Pochinok ◽

P. V. Anisimovich ◽

Z. A. Temerdashev

Keyword(s):

Shelf Life ◽

Spectrophotometric Determination ◽

Total Protein ◽

Biological Fluid ◽

Biological Fluids ◽

Measurement Techniques ◽

Protein Determination ◽

Analytical Properties ◽

The Impact

Determination of proteins in biological fluids is rather important for diagnostics in current clinical practice. The results of total protein determination depend on the amino-acid composition of the proteins present in the biological fluid. We discuss some aspects of the spectrophotometric determination of proteins in biological fluids, in particular, the methodological features of the technique based on the reaction of proteins with brompyrogallol red (BPGR). The most important advantage of BPGR in the determination of proteins in biological fluids is rather high and equal sensitivity of the dye to the proteins of albumin and globulin fractions, thus minimizing the errors attributed to the mismatch of the protein composition of the analyzed samples and calibration solutions used. The goal of the work is to study the impact of conditions and shelf life of the BPGR solution on the analytical properties of the solution in the spectrophotometric determination of proteins in biological fluids. Stability of the optical and analytical properties of BPGR solutions are studied using Fisher and Student criteria under conditions of different storage temperatures and nature of the stabilizer (ethanol or sodium benzoate) in the reagent solutions. Verification of the correctness of the total protein determination by the proposed method was carried out in spike tests. The introduced additives of standard solutions are prepared from the «Total protein» or «Albumin» calibrators. The developed method of the spectrophotometric determination of the mass concentration of proteins in the urine by the reaction with bromopyrogallol red was tested on real objects, metrologically certified and listed in the Federal register of certified measurement techniques. Analytical and metrological studies have shown that the developed method of protein determination with a reagent based on BPGR provides equal and high sensitivity of determination of albumin and globulin protein fractions in human biological fluids. To increase the shelf life of the reagent solution and preserve the analytical properties of the solution, we recommend to use ethanol as a stabilizer.

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Stabilization of dry immobilized acetylcholinesterase on microtitration plates for colorimetric determination of its inhibitors in water and biological fluids

Enzyme and Microbial Technology ◽

10.1016/s0141-0229(96)00077-4 ◽

1997 ◽

Vol 20 (1) ◽

pp. 18-23 ◽

Cited By ~ 8

Author(s):

Vu Khue Nguyen ◽

L. Ehret-Sabatier ◽

M. Goeldner ◽

C. Boudier ◽

G. Jamet ◽

...

Keyword(s):

Biological Fluids ◽

Colorimetric Determination

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Colorimetric Determination of Propofol in Bulk form, Dosage Form and Biological Fluids

Analytical Letters ◽

10.1080/00032710008543206 ◽

2000 ◽

Vol 33 (12) ◽

pp. 2515-2531 ◽

Cited By ~ 3

Author(s):

E.A. Gad-Kariem ◽

M.A. Abounassif

Keyword(s):

Dosage Form ◽

Biological Fluids ◽

Colorimetric Determination

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Simplified Colorimetric Determination of Thiocyanate in Biological Fluids, and Its Application to Investigation of the Toxic Amblyopias

Clinical Chemistry ◽

10.1093/clinchem/18.9.996 ◽

1972 ◽

Vol 18 (9) ◽

pp. 996-1000 ◽

Cited By ~ 164

Author(s):

A R Pettigrew ◽

G S Fell

Keyword(s):

Cigarette Smoking ◽

Analytical Procedure ◽

Biological Fluids ◽

Colorimetric Determination ◽

Subsequent Increase ◽

Cyanide Toxicity ◽

Colorimetric Procedure ◽

Colorimetric Reaction ◽

Hereditary Optic Atrophy

Abstract A colorimetric procedure for determination of small amounts of cyanide and thiocyanate, involving the synthesis of a pyridine dyestuff by the reaction of pyridine and an aromatic amine, has been simplified for the estimation of thiocyanate alone in biological fluids. Replacement of benzidine with p-phenylenediamine in the colorimetric reaction has both improved the precision of the analytical procedure and avoided a carcinogenic hazard. This method has been used to follow the decrease in plasma thiocyanate associated with abstinence from cigarette smoking, and its subsequent increase upon resumption. It has also been used to measure the plasma and urinary thiocyanate concentrations of patients suffering from the particular toxic amblyopias—tobacco amblyopia and Leber’s hereditary optic atrophy— believed to be associated with cyanide toxicity, and to follow the increased thiocyanate concentrations that accompany significant improvements in the patients’ vision brought about by various treatments.

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Colorimetric determination of total protein content in serum based on the polydopamine/protein adsorption competition on microplates

Talanta ◽

10.1016/j.talanta.2019.01.095 ◽

2019 ◽

Vol 198 ◽

pp. 15-22 ◽

Cited By ~ 3

Author(s):

Pasquale Palladino ◽

Alvaro Brittoli ◽

Emanuela Pascale ◽

Maria Minunni ◽

Simona Scarano

Keyword(s):

Protein Content ◽

Protein Adsorption ◽

Total Protein ◽

Total Protein Content ◽

Colorimetric Determination

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Application of a New Peroxide Indicator Reaction to the Specific, Automated Determination of Glucose with Glucose Oxidase

Clinical Chemistry ◽

10.1093/clinchem/18.9.943 ◽

1972 ◽

Vol 18 (9) ◽

pp. 943-950 ◽

Cited By ~ 166

Author(s):

Nathan Gochman ◽

Joan M Schmitz

Keyword(s):

Glucose Oxidase ◽

Biological Fluids ◽

Water Soluble ◽

Colorimetric Determination ◽

Indicator Reaction ◽

Reducing Substances ◽

Alkaline Ferricyanide ◽

Glucose 6 Phosphate Dehydrogenase ◽

Automated Methods

Abstract We describe an automated, colorimetric determination of glucose in biological fluids that combines the specificity of glucose oxidase and of a new peroxide indicator reaction. In the presence of peroxidase, 3-methyl-2-benzothiazolinone hydrazone oxidatively couples with N,N-dimethylaniline to form a stable, intensely colored, water-soluble indamine dye, the concentration of which is proportional to that of the third reactant, hydrogen peroxide. This reaction, used earlier to determine uric acid [Clin. Chem. 17, 1154 (1971)], is substantially less affected by negative interference of reducing substances than are previously described peroxide indicators. Results from use of AutoAnalyzers I and II and this method were compared with those from a manual spectrophotometric hexokinase/glucose-6-phosphate dehydrogenase procedure, and showed good correlation for specimens from patients. The automated methods are suitable for measuring glucose in serum, plasma from fluoride-or iodoacetate-preserved blood, urine (without ion-exchange pretreatment), or cerebrospinal fluid. They eliminate the problem of falsely high results caused by medication or reducing metabolites associated with uremia, in methods in which alkaline ferricyanide or copper—neocuproine is used.

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