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橙汁粉样品用N,N-二甲基甲酰胺提取,并离心分离,所得上清液中抗坏血酸与六甲基二硅氨烷和三甲基氯硅烷进行衍生反应,产物用正庚烷萃取。萃取液加入棕榈酸甲酯作为内标,供气相色谱-质谱分析。在气相色谱分离中用HP-5MS毛细管柱(30 m×250μm,0.25μm)为固定相,在质谱测定中采用全扫描模式。硅烷化抗坏血酸标准与内标峰面积的比值与硅烷化抗坏血酸的质量在1.0~5.0 mg范围内呈线性关系。方法用于橙汁粉样品中维生素C的测定,橙汁粉中维生素C的平均质量分数(n=6)为0.195 4%,回收率在92.3%~98.5%之间。 相似文献
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The chiral sulfido cluster (η5-EtO(O)CC5H4)RuCoMo(μ3-S)(CO)8 was synthesized by refluxing a solution of SRuCo2 (CO)9 and Na[Mo(CO)3CpC(O) OEt] in tetrahydrofuran. It was characterized by elemental analysis, IR and 1H-NMR.Crystal data: C 16H9O)10CoMoRuS, Mr=649.24, monoclinic, space group P21/n, a =10.075(1), b = 9.034(2), c = 22.973(7) A, β= 92.70(1), V = 2088.7(8)A3,296K, final R = 0. 030, Rw= 0. 042 for 3686 observed reflections with I>2. 00σ(I).The crystal structure determination shows that the cluster has a chiral tetrahedral core containing a ethoxycarbonyl attached to the cyclopentadienyl. 相似文献
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