pH-Sensitive gold nanoclusters: preparation and analytical applications for urea, urease, and urease inhibitor detection

2015 ◽  
Vol 51 (37) ◽  
pp. 7847-7850 ◽  
Author(s):  
Hao-Hua Deng ◽  
Gang-Wei Wu ◽  
Zhi-Qiang Zou ◽  
Hua-Ping Peng ◽  
Ai-Lin Liu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ph Value ◽  
Gold Nanoclusters ◽  
Ph Sensitive ◽  
Urease Inhibitor ◽  
Analytical Applications ◽  
Hydrolysis Of ◽  
Hydrolysis Of Urea

The urease-catalyzed hydrolysis of urea releases ammonia and carbon dioxide as products. The pH value increases as the urea degradation occurs, as a result, quenching the fluorescence of NAC-AuNCs.

The Formation of Plasma Acid at Atmospheric Pressure and its Application in Hydrolysis of Microcrystalline Cellulose

2013 ◽  
Vol 750-752 ◽  
pp. 1626-1629
Author(s):  
Bo Yuan ◽  
Ying Wang ◽  
Ying Chao Ji ◽  
Qiu Hong Wang
Keyword(s):  
Microcrystalline Cellulose ◽  
Atmospheric Pressure ◽  
High Performance ◽  
Barrier Discharge ◽  
Ph Value ◽  
Reducing Sugar ◽  
Dielectric Barrier ◽  
Integrated Optical ◽  
Hydrolysis Of ◽  
Single Factor Experiment

In this paper, plasma acid was obtained by treating distilled water with dielectric barrier discharge at atmospheric pressure in order to hydrolyze cellulose. The acidity of plasma acid was studied through a single factor experiment. A plasma acid with pH value of 1.42 was obtained and used to hydrolyze microcrystalline cellulose at 80°C for 60min. Under this condition, the integrated optical density (IOD) of the hydrolysis sample was 0.589. Based on standard glucose curve, the total reducing sugar (TRS) was calculated to be 53.75mg and the TRS yield was 53.75%. The filtrate was evaporated to get the solid hydrolysis sample to be analyzed by High-performance liquid chromatography (HPLC). The results showed that the sample mainly consisted of glucose, which proved that microcrystalline cellulose could be hydrolyzed by plasma acid. Therefore, it could be concluded that it was an environmentally friendly and economical method to hydrolyze the microcrystalline cellulose by plasma acid.

scholarly journals NH<sub>3</sub>-promoted hydrolysis of NO<sub>2</sub> induces explosive growth in HONO

2018 ◽  
Author(s):  
Wanyun Xu ◽  
Ye Kuang ◽  
Chunsheng Zhao ◽  
Jiangchuan Tao ◽  
Gang Zhao ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Ph Value ◽  
Primary Source ◽  
Field Measurements ◽  
Oh Radicals ◽  
The North ◽  
The North China Plain ◽  
First Time ◽  
Hydrolysis Of

Abstract. The study of atmospheric nitrous acid (HONO), which is the primary source of OH radicals, is crucial to atmospheric photochemistry and heterogeneous chemical processes. The heterogeneous NO2 chemistry under haze conditions was pointed out to be one of the missing sources of HONO on the North China Plain, producing sulfate and nitrate in the process. However, controversy exists between various proposed mechanisms, mainly debating on whether SO2 directly takes part in the HONO production process and what roles NH3 and the pH value play in it. In this paper, never before seen explosive HONO production (maximum rate: 16 ppb/hour) was reported and evidence was found for the first time in field measurements during fog episodes (usually with pH > 5) and haze episodes under high relative humidity (usually with pH 

SIGNIFICANT EFFECT OF PH ON PHOTOCATALYTIC DEGRADATION OF ORGANIC POLLUTANTS USING SEMICONDUCTOR CATALYSTS

2016 ◽  
Vol 78 (8-3) ◽  
Author(s):  
Nur Farhana Jaafar ◽  
Aishah Abdul Jalil ◽  
Sugeng Triwahyono ◽  
Adnan Ripin ◽  
Mohamad Wijayanuddin Ali
Keyword(s):  
Carbon Dioxide ◽  
Methyl Orange ◽  
Physicochemical Properties ◽  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Ph Value ◽  
Effect Of Ph ◽  
Electrolysis Method ◽  
Ph Range ◽  
Positively Charged

Photocatalytic is one of the inexpensive and non-toxic techniques for degradation of organic pollutants into harmless substances such as water and carbon dioxide. In this study, simple electrolysis method was used in preparation of Ag/TiO2 and α-Fe2O3/HY catalysts. The physicochemical properties of the catalysts were studied using XRD, FTIR, FESEM-EDX and surface area analysis. The pH of solution plays an important role in the photocatalytic degradation of organic pollutants which influences the surface-charge properties of the catalysts. Ag/TiO2 and α-Fe2O3/HY were used as catalyst on degradation of 2-chlorophenol (2-CP) and methyl orange (MO), respectively. The effect of pH on degradation of 2-CP and MO were investigated over a pH range from 2 to 9. Higher degradation of 2-CP and MO were obtained at pH 5 (74%) and pH 2 (80%), respectively. This finding might be explained by the amphoteric performance of the catalyst using point zero charge (pHZPC). The pHZPC for Ag/TiO2 and α-Fe2O3/HY was found to be at pH 6.3 and pH 7.2, respectively. Hence, the activities of the catalysts may have been affected by the existence of a strong electrostatic field between the positively charged catalysts surface and negatively charged 2-CP and MO caused a pH value lower than their pHZPC give greater degradation.

Colorimetric Screening Device for Pesticide Analysis Based on the Liposome

2013 ◽  
Vol 726-731 ◽  
pp. 850-853
Author(s):  
Hua Nan Guan
Keyword(s):  
Enzymatic Activity ◽  
Organophosphorus Pesticides ◽  
Ph Sensitive ◽  
Pesticide Analysis ◽  
Ph Indicator ◽  
Fluorescent Indicator ◽  
Fluorescent Signal ◽  
Low Levels ◽  
Screening Device ◽  
Hydrolysis Of

Monitoring of the organophosphorus pesticides dichlorvos at very low levels has been achieved with liposome-based nanobiosensors. The enzyme acetylcholinesterase was effectively stabilized within the internal nanoenvironment of the liposomes. Within the liposomes, the pH sensitive fluorescent indicator pyranine was also immobilized for the optical transduction of the enzymatic activity. Increasing amounts of pesticides lead to the decrease of the enzymatic activity for the hydrolysis of the acetylcholine and thus to a decrease in the fluorescent signal of the pH indicator. The decrease of the liposome biosensors signal is relative to the concentration of dichlorvos down to 10-12 M levels. Also a colorimetric screening device for pesticide analysis has been evaluated.

Crystalline nanoscale assembly of gold clusters for reversible storage and sensing of CO2via modulation of photoluminescence intermittency

2018 ◽  
Vol 6 (30) ◽  
pp. 8205-8211 ◽  
Author(s):  
Srestha Basu ◽  
Satyapriya Bhandari ◽  
Uday Narayan Pan ◽  
Anumita Paul ◽  
Arun Chattopadhyay
Keyword(s):  
Carbon Dioxide ◽  
Adsorption Capacity ◽  
Gold Nanoclusters ◽  
Gold Clusters ◽  
Gaseous Carbon Dioxide ◽  
Photoluminescence Intermittency ◽  
Nanoscale Assembly

We report that zinc mediated crystalline nanoscale assemblies of atomic gold nanoclusters (NCs) were able to reversibly store gaseous carbon dioxide with adsorption capacity of 1.79 mM g−1 at 20 °C and 20 bar.

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