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Cholerny Spammer
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 Posted: Fri 1:46, 10 Dec 2010 Post subject: http://www.wholesale-maccosmetics.org 1 - (2 - pyr |
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1 - (2 - pyridylazo) -2-- naphthol method for the determination of copper in tobacco
The absorbance, the absorbance for the vertical axis, the absorption wavelength of the abscissa mapping absorption curve (Figure 1), the measured maximum absorption wavelength of 552nm. 3.2 The working curve Imbibe 10 / ~ g / mLCu standard solution of the 0,0.1,0.2,0.3,[link widoczny dla zalogowanych],0.5,1.0,1.5 mL, were placed in 25mL volumetric flask, The method according to the color, 10min after the reagent blank as reference, measured at 552nm at the standard solution of various concentrations of cu absorbance, and absorbance plotted against the corresponding concentration cu, have to work curve (Figure 2) while the linear regression equation obtained: A = A 0.00181 +0.0419 Cr = 0.9926 where: A - absorbance; c - cu concentration (~ g/25mL). This shows that the working curve had good linearity in the 0-15 ~ g/25mL copper content law is obeyed. 11 repeated measurements to calculate the value of △ A relative standard deviation is 3.5%, detection limit was 2.4x10 ~. Wavelength (nm) Figure 1Cu, PAN absorption spectra with the amount of Cu} gn】 I_) Figure 2Ca2 working curve \within the range of .1 to 5.5 absorbance maximum and stable, so the selection of pH = 4.0 in the HAc. NaAc buffer solution control acidity. Meanwhile, the amount of buffer solution was tested with the following results. 5mL buffer solution that can be put in the amount of acidity control in the appropriate range,[link widoczny dla zalogowanych], so that the maximum measured absorbance and relatively stable. HAc-NaAc (mL) 2345678 Jing absorbance 0.520.540.600.610.610.600.593.4 the amount of color reagent to determine the amount of test results (see below) showed that the reagent consumption in the 1 3mL maximum absorption and stability within, when the dosage of more than 3mL color, with the reagent decreased the amount of the increase in absorbance. Experimental dosage of the selected color 2mL, get a better measurement results. Reagent (mL) 0.512345 absorbance 0.540.590.610.610.580.553.5 color temperature and system stability test (results below) that the system at room temperature, color, place 7min Fully color, more than 7min, system absorbance change is no longer with the storage time, and stable for at least 2h, 10min after the experimental determination of selection of place. Color Time (min) 6810121416 interference absorbance of 3.6 in the selected experimental conditions, the 0.1ptg/lmLCu were measured, the relative error ≤ 5%,[link widoczny dla zalogowanych], the following ions do not interfere (): K, N, Na, Zn, Cl A (3000); NO3, PO34 one, Fe3 (2500); Si a, Pb ¨, Mn2 (2000); Ba2,[link widoczny dla zalogowanych], Mg, Al (500); Bi ¨, cr3 (150); Ni, Hg2 ( 50), c02 (5). System better selectivity. Recovery of the late tobacco weighed 3.7 Yangpin 0.5000g, 1.0000g and 1.5000g of 3 copies were added to 10 ~ g / mLCu standard solution 0.3,[link widoczny dla zalogowanych],0.2,0.1 mL, according to the above method measurements. According to the measured results (Table 1), calculated recovery was 97.89% ~ 101.35%. Table 1 The recovery test (n = 5) 3.8 Comparison of two methods using an I (2 a-pyridylazo)-2 a naphthol method and atomic absorption spectrometry determination of the burley, flue-cured tobacco and Fresh copper content in the flue-cured tobacco, the results in Table 2. Table 2 Measurement results of smoke-like copper seen from Table 2, with 1 a (2 a-pyridylazo)-2 a naphthol method and measured with a GBC atomic absorption of copper, both the relative standard deviation 1.7% to 2.6%, and no significant difference, confirming the feasibility of the method, and an I (2 a pyridylazo) ... 2 naphthol reagents used method less simple, in the inadequate number of experimental conditions, no atomic absorption spectrophotometer research and teaching units, after all, a determination of copper content in tobacco a good way. 【References [1] [at] practical colorimetric analysis of inorganic Editorial Board, Zhang Quan name, war Jufang translation. Photometric analysis and practical elements of [M]. Shenyang: Liaoning Science and Technology Press ,1988.304-324. [2] Sun Wei Zhang, POSTGRADUATE, LIU Shao-Pu. Organic reagents in analytical chemistry applications 『M]. Beijing: Science Press, 1981.190.31
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