Papers by Keyword: Determination

Abstract: In Britton Robinson (B-R) buffer solution with pH = 7.00 and sodium dodecyl sulfate (SDS) medium, an effective energy transfer between acridine orange (AO) and Rhodamine B (RB) can occur, which can enhance the fluorescence of RB. The addition of Gemifloxacin (GMFX) can quench the fluorescence of RB. So a new method for the indirect determination of Gemifloxacin was established by AO-RB fluorescence resonance energy transfer. This method was applied to the determination of Gemifloxacin tablets. The results were consistent with those of high performance liquid chromatography (HPLC) . Experiments show that this method is simple, rapid, accurate and sensitive.

Abstract: A new method for the determination of nitrite was established based on cobalt monoxide (CoO) nanoparticles modified glassy carbon electrode (CS-CoO/GCE). In 0.15mol/L pH 4.0 HAc-NaAc, the CS-CoO/GCE showed a remarkable catalytic and enhancement effect on oxidation of the nitrite. A linear dynamic range of 8.0×10-7 to 6.0×10-3 mol/L (R=0.997) with a detection limit of 1.0×10-7 mol/L was obtained. The electrochemical mechanism was been obtained. This method has been used to determine the content of nitrite in real samples.

Abstract: Nondestructive determination of Au in gold ornaments mainly takes density method and X ray fluorescence spectrometer with energy dispersion (EDXRF), which exists disadvantages. This paper based on the principle of crystallography, deduced the mathematical relationship between the crystallographic parameters, the density and the impurities content in gold jewelry alloys, then introduced the results by density testing and determination of Ag and Cu by EDXRF into the mathematical relationship, and obtained the gold weight percent in gold jewelry alloys. The results show that obtained the gold weight percent and determination of Au by fire assay are almost consistent, which the error is less than 0.12 %, so establishes a synthesis method of determination of Au by EDXRF and density testing, solves the disadvantages which EDXRF only detects on gold jewelry surface and small area, and density testing cannot detect gold jewelry alloy and demands that jewelry shape is simple, and provides an effective synthesis way for determination of Au in gold jewelry alloys.

Abstract: Three principal components (cellulose, lignin, and hemicellulose) of coconut shell (CS), an abundant tropical biomass, were quantified using the Van Soest method. It was observed that CS had a high content of hemicellulose (30% of the raw CS material). The present study was undertaken to investigate the extractability of hemicellulose from CS obtained by ultrasound-assisted potassium hydroxide solution with the hydrogen peroxide method. The ultrasonic treatment and sequential extractions with alkali and alkaline peroxide under optimal conditions led to a release of more than 93% of the original hemicellulose. The effects of experimental variables, including pH value, reaction temperature and time, hydrogen peroxide content, and magnesium sulfate dosage on hemicellulose content were investigated. The obtained hemicelluloses were characterized by Fourier transform infrared spectroscopy (FT-IR), gel permeation chromatography (GPC), and comprehensive thermal analysis (TGA), which showed that potassium hydroxide significantly affected the yield of relatively pure hemicellulose.

Abstract: This paper summarized the measure methods which include both Chinese national standards and international standards of how to determine the concentration of Non-methane Hydrocarbons (NMHC).Some problems and suggestions were discussed in this paper to improve the level of the measure methods and prompt the establishment of relative Chinese national standard.

Abstract: 1-methyl-3-butyl Imidazole chloride is synthesized by 1–methyl imidazole and chlorinated n-butane. BMINO₃ ionic liquid is synthesized by BMIC and NaNO₃ in the acetone. The structure is characterized by infrared spectrometer. UV-spectrum curve is doned by scanning ionic liquid in 200~400nm wavelength range. The ionic liquid used in the experiment has obvious absorption in 200~400nm wavelength range, and the maximum absorption wavelength which is determined by ultraviolet spectrometry method is 228nm. Linear regression equation is y =0.02317x+0.06483. Correlation coefficient is 0.9995, which is high related degree between the absorbance value and the solution concentration. The recovery rate is between 99.8%~102%.

Abstract: A simple electrochemical method has been developed for the simultaneous determination of dihydroxybenzene isomers in wastewater samples with poly (glutamic acid) modified electrode (PGA/GCE). PGA/GCE was fabricated by electropolymerization of glutamic acid on a glassy carbon electrode (GCE) through cyclic voltammetry (CV). PGA/GCE showed an excellent electrocatalytic ability towards the oxidation of hydroquinone (HQ) and catechol (CC). With CV and differential pulse votammetric (DPV) measurements, HQ and CC in wastewater samples could be simultaneously analyzed at PGA/GCE. The linear range for HQ and CC were 5 - 100 μM and 2 - 160 μM, with a detection limit of 2.0 μM and 1.0 μM, respectively. Moreover, PGA/GCE exhibited good selectivity and repeatability. The method has a promising application in the monitoring of HQ and CC of wastewater.

Abstract: As one of the important quality indicators of organic heat carrier, the determination method of Viscosity Parameter has been greatly developed in recent years. In this paper, the traditional and new measurement methods have been summarized and introduced. Then it analyzed the current status and the existing problems of the measurement methods of Viscosity Parameter in our country, and it also prospected the development of the measurement methods of Viscosity Parameter of organic heat carrier. The new measurement method in recent years can be expected to viscosity measurement methods in the field of organic heat carrier along the following direction of development: (1)The traditional measurement methods will be further development and application; (2)The optical measurement techniques will be the most promising method for real-time measurement of viscosity in the organic heat carrier; (3) By using the method of modern data acquisition and processing to improve the traditional organic heat carrier viscosity measurement technology.

Abstract: Inductively coupled plasma optical emission spectrometric approach (ICP-OES) is used to determine the titanium content as principal component in pyrotechnic compositions used for fireworks and firecrackers. Element of titanium is commonly found in titanium powder in pyrotechnic compositions in fireworks and firecrackers. Statistical analysis shows that titanium content in pyrotechnics is between 3% to 25%. Concept of this method: considering the weight of the sample is 400mg,constant volume is 1L and the concentration of titanium is between 1 mg/L to 100 mg/L in sample solution, the determination scope of the method for the titanium content would be between 0.25% to 25%.Further experiments proved that the fitting correlation coefficient of titanium calibration curve is 0.9996 or higher, recovery is 100.06%‒105.30%.The allowable differential value is 0.4% between two single tests under repeatable conditions. This method can completely satisfy the requirements of the fireworks and firecrackers industry with high accuracy and good precision.

Abstract: At present, the height measure is an important content of image processing. But the height is determined by solar height angle achieved by look-up table, and the method is imprecise and inconvenient. To overcome such drawbacks, a novel determination method was proposed in the paper. First, the imaging time is adjusted to Solar Time. Then, the solar height angle at imaging time is calculated. Finally, the height of an object is calculated based on solar height angle and shadow length. The theoretical analysis and experiment results show that the proposed method is more effectual.