Flow- Injection Specrophotomemic Determination of Calcium Using PAN as a Color Agent.
2018 International Conference on Advanced Science and Engineering (ICOASE), Kurdistan Region, Iraq 394 978-1-5386-6696-8/18/$31.00 ©2018 IEEE
A spectrophotometric method for determination of Ca in aqueous solution using 1-(2-pyridylazo)-2-naphthol (PAN) as color reagent based on the formation of Ca-PAN Complex at pH 12 and measuring absorbance at 550nm, with molar absorptivity of 1.70×104 L.mol-1cm-1 has been modified to a flow injection-spectrophotometric (FI) method. The modified FI method is rapid, accurate, precise, and with low operation cost. The linear range of 1-8ppm was obtained with average recovery of 103.46 and precision of 1.5-3.4%. The proposed FI method using PAN as a color reagent was applied satisfactorily for the assay of Ca in natural water, milk, yogurt and human serum.
Standard Potential of the Silver-Silver Chloride Electrode in X% Ethylene Glycol - Water Mixtures at Different Temperatures
2018 International Conference on Advanced Science and Engineering (ICOASE), Kurdistan Region, Iraq. 978-1-5386-6696-8/18/$31.00 ©2018 IEEE
The physical properties (density, viscosity, and dielectric constant) of five different compositions (0, 10, 20, 30, and 40%) of ethylene glycol-water mixtures have been measured at nine temperatures from (278.15 to 318.15 K) which were utilized to calculate the standard potentials of the Silver-Silver Chloride electrode and the mean activity coefficient of ten different concentration of HCl ranged from (0.01-0.1m). The modeling of the investigated system was made based on an extended Debye-Hückel equation, using Galvanic cell without liquid junction 𝒑𝒕, 𝑯𝟐(𝒈,𝟏𝒂𝒕𝒎)│𝑯𝑪𝒍(𝒎), 𝑬𝑮 + 𝒘𝒂𝒕𝒆𝒓│𝑨𝒈𝑪𝒍(𝒔), 𝑨𝒈. The standard potential at different temperatures were utilized to calculate the standard thermodynamic quantities Δ𝑮°, Δ𝑯°, 𝒂𝒏𝒅 Δ𝑺° for the cell reaction. The results discussed in concerning with acid-base properties, solute-solvent interactions and the breakdown of the water structure on the addition of ethylene glycol.
Spectrophotometric Determination of Calcium with 1-(2-Pyridylazo)-2- Napthol Sensitized By Tween 80 Application to Various Samples
International Conference on Materials Engineering and Science IOP Publishing IOP Conf. Series: Materials Science and Engineering 454 (2018) 012089 doi:10.1088/1757-899X/454/1/012089
Spectrophotometric method for determination of Ca in aqueous solution using 1-(2- pyridylazo)-2-naphthol (PAN) as colour reagent has been developed. The method was based on the formation of Ca-PAN complex at pH 12 and measuring absorbance at 550nm, with molar absorptivity of 1.70x104 L.mol-1cm-1, average recovery is 101.72 and precision (RSD) is better than ±2.8% indicating that the method is relatively sensitive, accurate and precise. The binary system of Ca(PAN)2 and conditional stability constant of 1.467x1010 L2.mol-2 adherence of Beer’s law over concentration range 0.08-2ppm. The method was applied for the determination of Ca in natural water, milk, yogurt, human serum, grip and tomato juice satisfactory. In presence of 1% tween 80 and composite masking agents of pH 11.5 the absorbance measurements were made at 540nm giving molar absorptivity of 2.7x104 L.mol-1 cm-1 , average recovery of 101.2 and precision (RSD) better than ±3% indicating that the Ca(PAN)2 system is sensitive, accurate, and precise. In addition it is considered to be simple, rapid and do not need heating or solvent extraction steps, moreover it can be applied successfully for the assay of Ca in various samples over concentration range of 0.0008-0.8ppm.
Enhanced Photoelectrochemical Water Splitting of Hydrothermally- Grown ZnO and Yttrium-doped ZnO NR Arrays
International Conference on Materials Engineering and Science IOP Publishing IOP Conf. Series: Materials Science and Engineering 454 (2018) 012033 doi:10.1088/1757-899X/454/1/012033
Undoped and Y doped ZnO nanorods (YZO NRs) were prepared by hydrothermal method. The as-prepared ZnO and YZO NRs with different Y/Zn molar ratios were used as anodes for electrochemical water splitting. Then, photoelectrochemical (PEC) water splitting performances of YZO NRs were tested. When compared with pristine ZnO NRs, the photocurrent density generated with yttrium doped zinc oxide NR as electrode was higher(1.2 mA cm-2 ) than that obtained with pristine ZnO NRs (0.25 mA cm-2), at 0.2 V vs. Ag/ AgCl using samples of 1.2 mol % of yttrium. This performance corresponds to calculated photoconversion efficiency of 0.40%, at a low potential (-0.38V vs Ag/AgCl) of the non-doped ZnO NR film.