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A new capillary electrophoresis method for determining poly-beta-hydroxybutyric acid (PHB) in Bacillus thuringiensis was established. Poly-beta-hydroxybutyric acid in samples was hydrolyzed by sulphuric acid and neutralized by Ba(OH)2. The content of produced beta-hydroxybutyrate was then determined by capillary zone electrophoresis (CZE) with indirect UV detection at 254 nm. With 5 mM p-hydroxybenzoate and 0.5 mM tetradecyltrimethylammonium bromide (TTAB) at pH 8.0 as carrier electrolyte, beta-hydroxybutyrate can be determined within 6 min. Standard regression equation was made by beta-hydroxybutyrate, and the linear range was 2-1000 microg/ml. The relative standard deviations (RSDs) for migration time and peak area are both less than 1.0%. The detection limit for beta-hydroxybutyrate was 0.2 microg/ml, which is two to three orders of magnitude lower than that of the gas chromatography (GC) method. The capillary electrophoresis method was successfully applied to determine poly-beta-hydroxybutyric acid in fermentation broth and single colony. The added standard recovery was 96%. 相似文献
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Han JH Yoo SK Seo JS Hong SJ Kim SK Kim C 《Dalton transactions (Cambridge, England : 2003)》2005,(2):402-406
The systematic oxidation reactions of a wide range of alcohols have been carried out by using an iron porphyrin complex in order to understand their relation to cytochrome P-450 enzymes and to have a practical application to organic synthesis. The iron porphyrin complex catalyzed efficiently alcohol oxidation to the respective carbonyl compound via a high-valent iron-oxo porphyrin intermediate ((Porp)Fe=O+). Several mechanistic studies such as isotope 18O labeling, deuterium isotope effect, linear free energy relationship, and ring-opening of radical clock substrate, have suggested that the alcohol is oxidized by a sequence of reactions involving an alpha-hydroxyalkyl radical intermediate and oxygen rebound to form the gem-diol, dehydration of which yields the carbonyl compounds. Moreover, it has been proposed that a two-state reactivity mechanism can also be adopted for alcohol oxidation reactions in iron porphyrin model systems as exhibited by P-450 enzymes. 相似文献
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微波等离子体光谱法测定碲的研究 总被引:2,自引:0,他引:2
微波等离子体原子发射光谱法(MIPAES)测定碲,前人已作过一些工作。本文利用我们建立的微量进样系统与MIPAES联用,对碲的测定进行了研究。实验中发现,加入适量的SnCl_2可降低检出限约一个数量级,Te_(214.3nm)的检出限为5 ng/mL,同时还研究了碱金属卤化物对碲的测定的影响。 相似文献