| 1. Objective: to establish a new method for the separation and determination of trace vitamin B2. Methods: adopt the Aqueous Two Phase Extraction Based On PEG -(NH4)2SO4 to extract VB2, then determine the fluorescence of organic part byλex/λem=448.0/526.0nm. Results: The results suggest that the extraction efficiencies of vitaminB2 between the PEG6000-salt system was91%93%in one-step extraction. the extraction method gave linear dynamic ranges of 8.52×10-61.5×10-4 g/L with detection limits of 7.0×10-6 g/L. Conclusion:This method has dramatic advantages such as high extraction efficiency, long linearity, little detection limits etc,apply to the determination of vitamin B2.2. Objective: To establish a new method for the separation and determination of trace vitamin B6. Methods: Adopt the Aqueous Two Phase Extraction Based On PEG -(NH4)2SO4 to extract VB6, then determine the fluorescence of organic part byλex/λem=325/398nm. Results: The results suggest that the extraction efficiencies of vitaminB6 between the PEG6000-salt system was more than95%in one-step extraction. The extraction method gave linear dynamic ranges of 6.0×10-63.0×10-5 g/L ,with detection limits of 6.0×10-6 g/L. Conclusion:This method has dramatic advantages such as high extraction efficiency ,little detection limits etc,apply to the determination of vitamin B6.3. Objective Sought to establish a new way for the etermination of trace vitamin B1 by Fluorimetry after Aqueous Two Phase Extraction. Methods The experiment first to use sodium molybdate as the oxidants of vitamin B1, take appropriate oxidation of thiamine to the separating funnel which has been filled with PEG 6000,sodium citrate and buffer after oscillation,put it aside , separating the upper and lower phase,determin the fluorescence of organic phase at best wavelength of 310nm/441nm. Results Under the optimal conditions , the extraction method gave linear dynamic ranges of 4.0×10-72.0×10-5 g/L ,regression equation: y =52.79+21.86x,with detection limits of 0.46 ng/mL.The percent recovery was 96.3103.8% and the relative standard deviation was 0.81.5%. Conclusion compared with other methods, this method has dramatic advantages such as simple operation ,hign sensitivity and low toxicity etc,apply to the determination of vitamin B1.4. Objective Seeking a higher sensitivity aqueous two-phase system for the determination of trace vitamin B6. Methods Based on the convergence of PEG and PVP to improve the extraction of trace vitamin B6, so as to achieve the purpose of improving sensitivity. Results In the best conditions, the experimental determination of vitamin B6 in the linear range of 8.0×10-7 2.4×10-5 g / L, detection limit: 6.0×10-7 g/L, recovery of 88.4398.78%.Conclusion Compared with the extraction of single polymer aqueous two-phase, Aqueous two-phase combination has dramatic advantages such as highly reliable, less salt, high sensitivity etc.5. Based on water-miscible solvent,such as ionic liquid, can be used to form aqueous two-phase system for extraction of analytes in the presence of salts, develop ionic liquid-salt system of ionic liquid( [Bmim]Br )and(NH4)2SO4 for the determination of trace vitamin B6 coupled with fluorimetry after aqueous two-phase extraction. Many factors to the extraction efficiencies of vitamin B6 containing pH , the amount of extractant and extraction time were well studied. Under the optimal conditions thatλex/λem =342nm/418nm,pH=8.69, the amount of ionic liquid and ammonium sulfate were 1.3mL, 2.8g ,extraction time was 3.0 min, the extraction method gave linear dynamic ranges of 1.6×10-7 1.04×10-5g/L ,with detection limits of 4.8×10-7g/L .6. Based on the strong accumulation of polymer synthesis and the high sensitivity of fluorescence quenching ect,we prosed a new method for the determination of trace vitamin B2by fluorescence quenching after aqueous two-phase extraction .The paper discusses the extractant, extraction time,acid , the concentration of chromium nerazzurri R, quenching time etc factors, and studied the mechanism of using vitamin B2 cu destroy chromium nerazzurri R.The linear range of vitamin B2 was 6.0×10-87.2×10-6g/L, regression equations: F = 0.22 + 2.94 C ; correlation coefficient was 0.99887; detect limit:3.06×10-7g/L;the relative standard deviation was 2.9-5.6%.Compaered with other analysis for vitamin B2, this method has characteristics such as : low detect limit, wide linear range, low-toxic, pro-environment etc. |
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