Phenol standard curve by UV-1200 ultraviolet spectrophotometry - Database & Sql Blog Articles

Phenol standard curve by ultraviolet spectrophotometry

Key words: ultraviolet spectrophotometry; drawing of standard curve; analysis instrument ; UV-1300; UV-1500 I. Experimental purpose 1. Master UV spectroscopy for qualitative and quantitative analysis The basic principle; 2, learn how to use the UV-visible spectrophotometer. 2. Experimental Principle The organic compound containing a benzene ring and a conjugated double bond has characteristic absorption in the ultraviolet region. Different material structures are selective for the absorption of ultraviolet and visible light. Among them, the maximum absorption wavelength λ, the molar absorption coefficient ε and the shape of the absorption curve are the basis for qualitative analysis of the substance. Since the absorbance A has the maximum value at λmax, the change of A with the concentration is the most obvious at this wavelength, and the sensitivity of the method is the largest. Therefore, the absorption spectrum curve of the phenol aqueous solution (test solution) on the ultraviolet spectrophotometer is further analyzed by the curve. Find λmax and quantify the material accordingly. When using the UV spectrophotometer for quantitative analysis, if the concentration of the analyte is too low or too high, the transmittance reading can be extended by 10 times or reduced by 10 times, which is beneficial to the analysis of low concentration or high concentration. The principle of the method is According to Lambert-Beer's law: A = εbc. Third, the main instruments and reagents Main instruments: U.S. UV-visible spectrophotometer UV-1300; UV-1500; 1cm quartz absorption cell 2; 50mL colorimetric tube 5; 5mL, 1; Reagent: phenol standard solution: 100mg/L; IV. Experimental procedure (1), preparation of analytical solution Take 5 50mL colorimetric tubes, and accurately add 0.5mL, 1mL, 1.5mL, 2.0mL, 2.5 respectively with pipette The phenol standard solution with a concentration of 100 mg/L was diluted with deionized water to a 25 mL mark and shaken. Experimental data is recorded in a standard table. (2) Determine the maximum absorption wavelength to obtain a phenol standard solution with a concentration of 8 mg/L after dilution. On a UV-Vis spectrophotometer, use a 1 cm quartz absorption cell and deionized water as a reference solution in the wavelength range of 200 to 330 nm. The inside was scanned to plot the absorption curve of phenol. Find λmax1, λmax2 on the curve. (3) Preparation of standard curve The phenol standard solution of each concentration is measured by using a 1 cm quartz absorption cell and deionized water as a reference solution, and measuring the absorbance of each solution in order from the lowest to the highest concentration in the selected maximum wavelength. Experimental data is recorded in a standard table. A standard working curve is made by plotting the absorbance versus concentration. V. Data record and result analysis standard curve Keywords: ultraviolet spectrophotometry; standard curve drawing; US analysis instrument ; UV-1300; UV-1500