D-Isoascorbyl stearate(D-IAS)was synthesized by the transesterification of D-isoascorbic acid and methyl stearate using concentrated sulfuric acid as reaction medium and catalyst in 73% yield.D-IAS is characterized by...D-Isoascorbyl stearate(D-IAS)was synthesized by the transesterification of D-isoascorbic acid and methyl stearate using concentrated sulfuric acid as reaction medium and catalyst in 73% yield.D-IAS is characterized by FT-IR.The iodimetry test shows the solubility of D-IAS in vegetable oil such as tea seed oil,peanut oil,rape oil and sesame oil is much greater than D-isoascorbic acid,and the antioxidation tests by GB/T5009.37-1996 shows that D-IAS is a good antioxidant with good solubility in oil.展开更多
采用HILIC色谱柱,利用高效液相色谱分离L-抗坏血酸和D-异抗坏血酸,考察了流动相的组成、柱温和流速对分离L-抗坏血酸和D-异抗坏血酸的影响.结果表明:流动相为乙腈-0.1%磷酸(93∶7),流速为0.8 m L·min^(-1),柱温为20℃,检测波长为24...采用HILIC色谱柱,利用高效液相色谱分离L-抗坏血酸和D-异抗坏血酸,考察了流动相的组成、柱温和流速对分离L-抗坏血酸和D-异抗坏血酸的影响.结果表明:流动相为乙腈-0.1%磷酸(93∶7),流速为0.8 m L·min^(-1),柱温为20℃,检测波长为243 nm的条件下,分离效果最优,分离度为7.79.该方法进一步应用于3种维生素C实际样品中抗坏血酸含量的测定,3种样品中均仅有L-抗坏血酸检出,其含量在96.62~985.8 mg·g^(-1)之间,相对标准偏差在0.65%~0.94%之间.展开更多
文摘D-Isoascorbyl stearate(D-IAS)was synthesized by the transesterification of D-isoascorbic acid and methyl stearate using concentrated sulfuric acid as reaction medium and catalyst in 73% yield.D-IAS is characterized by FT-IR.The iodimetry test shows the solubility of D-IAS in vegetable oil such as tea seed oil,peanut oil,rape oil and sesame oil is much greater than D-isoascorbic acid,and the antioxidation tests by GB/T5009.37-1996 shows that D-IAS is a good antioxidant with good solubility in oil.
文摘采用HILIC色谱柱,利用高效液相色谱分离L-抗坏血酸和D-异抗坏血酸,考察了流动相的组成、柱温和流速对分离L-抗坏血酸和D-异抗坏血酸的影响.结果表明:流动相为乙腈-0.1%磷酸(93∶7),流速为0.8 m L·min^(-1),柱温为20℃,检测波长为243 nm的条件下,分离效果最优,分离度为7.79.该方法进一步应用于3种维生素C实际样品中抗坏血酸含量的测定,3种样品中均仅有L-抗坏血酸检出,其含量在96.62~985.8 mg·g^(-1)之间,相对标准偏差在0.65%~0.94%之间.
