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%.

scholarly journals Hydrogen-Bonding Recognition-Induced Colorimetric Determination of Hydrazine Based on the Tryptophan Capped Gold Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Wenhua Gao ◽  
Jing Xi ◽  
Yunsheng Chen ◽  
Song Xiao ◽  
Xingqing Wang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Detection System ◽  
Colorimetric Method ◽  
Cost Effective ◽  
Colorimetric Determination ◽  
Chloroauric Acid ◽  
Sample Analysis ◽  
Higher Temperature

A simple, cost-effective, and rapid colorimetric method for hydrazine detection using tryptophan-caped gold nanoparticles (Trp-AuNPs) has been developed. Tryptophan (Trp) is a protein with reducibility and amino group which can reduce chloroauric acid (HAuCl4) to AuNPs and modify the surface of AuNPs simultaneously. The Trp-AuNPs could be used to quantitatively detect hydrazine and showed different responses to vary concentration of hydrazine in an aqueous solution based on the aggregation-induced color change of Trp-AuNPs. The real water sample analysis verified the conclusion. The sensitivity of the detection system was influenced by the size of AuNPs which is determined by the pH of the detection system, the concentration of Trp, and the react time. We found that higher temperature contributed to more rapidly results. The detection system can detect as low as 1 μM hydrazine. We expect our approach to have wide-ranging applications in the developing region for monitoring water quality in some areas.

scholarly journals Facile and Green Fabrication of Carrageenan-Silver Nanoparticles for Colorimetric Determination of Cu2+ and S2−

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 83 ◽  
Author(s):  
Yesheng Wang ◽  
Xueyi Dong ◽  
Li Zhao ◽  
Yun Xue ◽  
Xihui Zhao ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Lake Water ◽  
Color Change ◽  
Tap Water ◽  
Environmental Water ◽  
Colorimetric Determination ◽  
Capping Agent ◽  
Colorimetric Sensing ◽  
Green Method

In the present work, silver nanoparticles (AgNPs) were prepared by a simple and green method using carrageenan as reducing and capping agent. The as-synthesized carrageenan-AgNPs was demonstrated as an effective duel colorimetric sensing for selective and sensitive recognition of Cu2+ and S2−, which could be used to detect these ions with naked eyes. In addition, the possible sensing mechanism was that Cu2+ ions caused serious aggregation of carrageenan-AgNPs, which led to the color change of carrageenan-AgNPs. AgNPs were etched by S2− forming Ag2S, which played an important role in the determination of S2− ions. Furthermore, it has been successfully applied to the determination of Cu2+ and S2− in tap water and lake water, showing its great potential for the analysis of environmental water samples.

scholarly journals Silver Nanoplates for Colorimetric Determination of Xanthine in Human Plasma and in Fish Meat via Etching/Aggregation/Fusion Steps

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5739
Author(s):  
Hung-Cheng Hsu ◽  
Pei-Wen Liao ◽  
Hsiang-Tzu Lee ◽  
Wei-Chen Liu ◽  
Mei-Lin Ho
Keyword(s):  
Blood Plasma ◽  
Color Change ◽  
Colorimetric Method ◽  
Partial Substitution ◽  
Colorimetric Determination ◽  
Detection Mechanism ◽  
Silver Nanoplates ◽  
Fish Meat ◽  
In Blood Plasma

Silver nanoplates (AgP) were prepared and used in a colorimetric method for the evaluation of Xanthine (Xan) in blood plasma and fish meat. The detection mechanism for Xan was observed to occur via etching of AgP particles/aggregation/fusion steps, resulting in a color change from blue to grey. First, the basic Xan solution is adsorbed through partial substitution of capping molecules around the AgP with Xan, and then intermolecular hydrogen bonds form between AgP and AgP. Subsequently, the titrant Xan solution further etches the AgP and finally fuses particles together. Owing to the step by step mechanism, the response range towards Xan has two linear regression ranges: 0.15–0.60 μM and 0.61–3.00 μM, respectively. The detection limit in the range of 0.15–0.60 μM is 0.011 μM (S/N = 3). AgP exhibits good selectivity for Xan over other potential interferents such as amino acids and blood proteins. AgP achieves rapid detection of Xan and can be applied to the satisfactory determination of Xan in blood plasma and fish meat. This colorimetric sensor is easy to use, cost effective, fast, selective and user friendly.

The Need for Using An Enzymatic Colorimetric Assay in Creatinine Determination of Peritoneal Dialysis Solutions

1990 ◽  
Vol 10 (1) ◽  
pp. 89-92 ◽  
Author(s):  
Liliane Larpent ◽  
Christian Verger
Keyword(s):  
Peritoneal Dialysis ◽  
Reliable Method ◽  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Peritoneal Membrane ◽  
Creatinine Kinetics ◽  
Dialysis Solutions ◽  
Peritoneal Dialysis Solutions ◽  
Enzymatic Test

The fate of the peritoneal membrane on continuous ambulatory peritoneal dialysis (CAPD) is usually evaluated through the modification of its permeability to various solutes as glucose, creatinine, and urea. Therefore, the accuracy of the methods used for measurements of creatinine is of great importance. A particular problem does exist for creatinine determination as it may be influenced by the presence of glucose. We studied a new enzymatic colorimetric method for creatinine determination in peritoneal dialysis solutions which contain high dextrose concentrations. Creatinine was measured in plasma, urine, and dialysate from 18 patients on CAPD and in pure dextrose solutions, with an enzymatic test (Boehringer Mannheim) and with Jaffe's reaction on two different analyzers: Astra (Beckman) and Eris (Merck). Creatinine results were similar with both assays (Jaffe's reaction and enzymatic test) when measured in blood and urine. However the Jaffe's reaction gave higher creatinine results than the enzymatic test (p < 0.001), when assays were performed in peritoneal dialysis solutions and in pure glucose solutions. In addition, it appeared that other components of dialysis solutions, mainly calcium chloride, influenced unpredictably the results of creatinine with the Jaffe's reaction. We conclude that specific enzymatic test is a more accurate and reliable method to evaluate creatinine kinetics through the peritoneal membrane when determined in CAPD solutions.

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.

Quantitative Determination of Thiourea in Citrus Fruits

1977 ◽  
Vol 60 (3) ◽  
pp. 699-701
Author(s):  
Bernadette Mandrou ◽  
Suzanne Brun ◽  
Amara Kingkate
Keyword(s):  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Extraction Technique ◽  
Citrus Fruits ◽  
Alumina Column ◽  
Orange Peels ◽  
Ultraviolet Reflectance ◽  
Spectrometric Measurements ◽  
Colorimetric Reaction

Abstract A quantitative method for thiourea determination in orange peels is proposed, with direct reflectance spectrometric measurements on chromatoplates. Thiourea is separated on a silica gel plate with methanol-chloroform (10+90), and the spots are characterized with 2,6-dichloroquinone chloroimide; this colorimetric reaction is unstable, so thiourea is quantitated on the chromatogram by direct ultraviolet reflectance spectrometric measurements at 240 nm. Comparison between this method and the AOAC colorimetric method shows interferences and higher results in the colorimetric assay. By slightly modifying the extraction technique, such as purifying the extract on an alumina column, it is possible to decrease these interferences and to avoid erroneous results with the AOAC colorimetric method. For both methods, colorimetry in solution and reflectometry on chromatoplates, applied after the proposed extraction technique, the sensitivity is about 1 ppm and the reliabilities are similar.

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.

Determination of alpha 2-macroglobulin-trypsin complex with a new synthetic substrate.

1989 ◽  
Vol 35 (11) ◽  
pp. 2169-2172 ◽  
Author(s):  
K Kuroiwa ◽  
S Nakatsuyama ◽  
K Katayama ◽  
T Nagasawa
Keyword(s):  
Healthy Subjects ◽  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Pancreatic Disease ◽  
Chromogenic Substrate ◽  
Standard Curve ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Abstract We have developed a colorimetric assay for quantifying alpha 2-macroglobulin-trypsin complex (alpha 2M-TRY) in human serum, based on use of a new chromogenic substrate D-gamma-tert-butyloxy-Glu-Gly-Arg-3-carboxy-4-hydroxyanilide dihydrochloride (PS-3001). Within-run CVs by this assay were 4.76%, 1.57%, and 0.83% for trypsin complex concentrations of 3.1, 12.2, and 48.1 U/L, respectively (n = 10 each). Between-day CVs were 5.38%, 3.12%, and 2.20% at each concentration, respectively (n = 7). Mean analytical recoveries of alpha 2M-TRY added to serum were 100%, 105%, and 101% for 9.2, 15.1, and 46.3 U/L, respectively (n = 2). The standard curve obtained was linear up to 330 U/L. We applied this method to the study of alpha 2M-TRY activity in sera from 97 healthy subjects (group 1), from 27 patients with acute pancreatitis (group 2), and from 25 patients with other chylopoietic diseases (group 3); results ranged from 0 to 1.2 U/L (mean = 0.5, SD = 0.3), from 1.2 to 77.4 U/L (mean = 14.6, SD = 19.0), and from 0 to 1.3 U/L (mean = 0.4, SD = 0.3), respectively. Concentrations of enzymatically active alpha 2M-TRY were significantly greater in sera from group 2 than in groups 1 and 3. The determination of serum alpha 2M-TRY activity by this simple, rapid, colorimetric method may be useful for the diagnosis and evaluation of pancreatic disease.

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.

Sign in / Sign up

Export Citation Format

Share Document