反相高效液相色谱法测定维生素D_2和维生素D_3

提出了用反相高效液相色谱法(RP-HPLC)分离和测定胶囊、油状试剂中维生素D2及维生素D3的含量。样品用甲醇超声提取,提取液用甲醇定容至100mL,经0.45μm滤膜过滤后供HPLC分析。采用Zorbax SB-C18反相色谱柱及C18保护柱作为分离柱,乙腈作为流动相,流量为1.0mL.min-1,在波长265nm处作紫外检测,进样量为20μL。维生素D2和维生素D3的质量浓度在0.50～20mg.L-1范围内与相应的峰面积呈线性关系,测得检出限(3S/N)依次为0.030,0.026mg.L-1。此方法应用于实样分析并在此基础用标准加入法做回收试验,同时进行精密度试验,测得回收率在95.0%～99.4%之间,测定值的相对标准偏差(n=6)在1.2%～2.6%之间。     

高效液相色谱-串联质谱法测定食品中维生素D_2和维生素D_3

提出了食品中维生素D2和维生素D3的高效液相色谱-串联质谱分析方法。食品样品经氢氧化钾皂化后乙醚萃取,所得有机相经无水硫酸钠除水后蒸发至干。用1 mL乙醇溶解后经Agilent Zorbax XDB C18色谱柱(2.1 mm×50 mm,3.5μm)分离,用甲-醇10 mmol·L-1乙酸铵溶液(90+10)的混合溶液洗脱,采用电喷雾正离子模式多反应监测。维生素D2和维生素D3的线性范围均为50~500μg·L-1,检出限(3S/N)均为10μg·L-1。方法应用于测定奶粉和酸酸乳中维生素D2和维生素D3,回收率在76.8%~83.9%之间。     

HPLC-APCI(+)-MS/MS测定乳制品中的维生素D_2及D_3

建立了一种高效液相色谱-大气压化学电离串联四极杆质谱,正离子监测模式下(HPLC-APCI(+)-MS/MS)测定乳制品中维生素D2和D3的方法。样品经皂化后,用石油醚提取,提取液经无水硫酸钠干燥,在氮气保护下旋转蒸发浓缩至10 m L以下,氮气吹干,用10 m L甲醇溶解后,经ACQUITY UPLC BEH C18色谱柱(1.7μm,2.1 mm×100 mm)分离,甲醇-水(95∶5)洗脱,多反应监测模式测定。维生素D2和D3在0.01~0.2 mg/L范围内呈良好的线性关系,相关系数(r2)分别为0.998 7和0.999 1,方法回收率为83.0%~99.4%,相对标准偏差(RSD)为2.0%~8.3%。     

反相高效液相色谱法测定补钙保健品中的维生素D_3

 用氯仿作提取剂直接提取补钙保健品中的维生素Ｄ３,提取液经浓缩后进行高效液相色谱分析,并对皂化和直接提取的样品中维生素Ｄ３的含量进行了比较。采用μ－ＢｏｎｄａｐａｋＣ１８作分离柱,甲醇－水（８７１３）作流动相,检测波长为２６４ｎｍ,回收率为９５．６３％。     

反相高效液相色谱法测定补钙保健品中的维生素D_3

用氯仿作提取剂直接提取补钙保健品中的维生素Ｄ３，提取液经浓缩后进行高效液相色谱分析，并对皂化和直接提取的样品中维生素Ｄ３的含量进行了比较。采用μ－ＢｏｎｄａｐａｋＣ１８作分离柱，甲醇－水（８７１３）作流动相，检测波长为２６４ｎｍ，回收率为９５．６３％。     

13α-取代-去-C-环-19-去亚甲基-1α,25-二羟基维生素D_3类似物的合成

以维生素D3为起始原料,经臭氧化,Baeyer-Villiger氧化内酯化,开裂六元环,二氧化钌(RuO2)引进C-25位羟基,最后经Horner-Wittig反应偶合D环和A环得到13-取代-去-C-环-19-去亚甲基-1α,25-二羟基维生素D3类似物(12a,12b).     

HPLC同时测定保健食品中维生素A、D3、E和β-胡萝卜素

建立了一种同时测定保健食品中维生素A、D3、E、β-胡萝卜素的高效液相色谱法。样品皂化后乙醚提取,旋转蒸干,流动相溶解,HPLC紫外检测。实验结果显示,VA、VD3、VE和β-胡萝卜素的线性范围分别为0.012~500、0.030~500、0.12~500和0.015~500μg/mL,且浓度范围内线性良好;检出限分别为0.24、0.60、2.40和0.30μg/g;相对标准偏差分别为1.9%、3.4%、4.6%和2.9%;VA、VD、VE和β-胡萝卜素的加标回收率为84.8%~119.0%。分析周期在20 min以内,方法适合保健食品样品的分析。     

液相色谱-串联质谱法检测干血点样本中25-羟基维生素D2和25-羟基维生素D3

建立了一种高通量液相色谱-串联质谱技术检测干血点(DBS)样本中25-羟基维生素D2[25(OH)D2]和25-羟基维生素D3[25(OH)D3]的方法.以DBS为样本,以4-苯基-1,2,4-三唑啉-3,5-二酮(PTAD)为试剂进行分析物衍生化,所需样本量仅约相当于6μL全血当量的DBS样本;使用甲醇直接超声提取分析物,避开了通常情况下DBS样本前处理中的全血复溶和蛋白质沉淀等繁琐步骤;整个前处理过程使用自动化液体处理平台实现自动化操作和高检测通量;以25(OH)D2-D6和25(OH)D3-D3为同位素内标,消除基质效应的影响.前处理后的样本进行LC-MS/MS分析,使用C18柱进行分离,流动相为甲醇(含5 mmol/L甲酸铵)-水(含5 mmol/L甲酸铵)(75:25,V/V),洗脱时间为4 min,使用多反应监测模式(MRM)定量.结果表明:25(OH)D2和25(OH)D3的检出限为0.12 ng/mL(S/N=3),定量限为0.94 ng/mL(S/N=10).25(OH)D2和25(OH)D3在0.94~120.00 ng/mL范围内线性关系良好,日内相对标准偏差(RSD)分别为1.4%~8.6%和3.7%~15.5%,日间RSD分别为4.0%~5.3%和3.8%~14.9%,平均回收率分别为91.7%±7.9%~108.5%±6.5%和94.8%±6.8%~101.3%±2.9%.DBS样本在不同温度(-20℃,22℃,37℃)下储存不同时间(0,1,2,3,5,7,14天)后的稳定性实验显示样本总体RSD°15%.以25(OH)D参考物质NIST SRM 972a中的Level 3制备标准DBS样本,25(OH)D2和25(OH)D3的回收率分别为110.3%和103.0%.     

Synthesis of an optically active intermediate for A-ring of 19-nor- 1α,25-dihydroxyvitamin D3

An optically active intermediate 5 for A-ring of 19-nor-1a,25-dihydroxyvitamin D3 2 has been synthesized in five steps, starting from readily available, inexpensive D( )-xylose 6 with good yield.     

魔方状微纳结构BaTiO3的制备及其压电催化性能

在简单溶剂热条件下,通过控制钡、钛物质的量之比制备了魔方状微纳结构BaTiO₃粉体,并以5 mg·L^-1罗丹明B(RhB)溶液为降解对象测试其压电催化性能。采用扫描电子显微镜、X射线衍射、傅里叶变换红外光谱对所制备粉体的物化性质进行详细表征,并测试其压电、光催化活性及循环稳定性。结果表明,钡、钛物质的量之比为1∶1时,合成的粉体为由立方体组装而成的魔方状四方相结构的BaTiO₃。在40 kHz、360 W的超声条件下,180 min内的降解率达90%,5次循环后的降解率为79.7%,变化率为11.4%,优于其光催化性能,具备优异的压电催化活性及循环稳定性。     

Effect of Reaction Media on Photoreaction of Provitamin D_3

IntroductionThe photochemistry of provitamin D3 (Pro) has been studied extensively in many years1-4. As shown in Scheme 11, irradiation of provitamin D3 in organic solvents results in its photoisomerization to previtamin D3 (Pre). Previtamin D3 can be thermally transferred into vitamin D3 (VD3), which is of commercial interests. However, previtamin D3 also undergoes the photochemical back reaction leading to the regeneration of provitamin D3 and the photoisomerization resulting in the und…     

维生素D包合物中维生素D的高效液相色谱测定

Vitamin D in the VDHCD inclusion complex was determined by HPLC on a Resolve silica column usingamobile phase of n-hexane:n-amylalcohol=95:5(V/V)and UV detection at 254 nm.The quantitative de-termination was performed with dimethyl phthalate as the internal standard.     

Efficient Synthesis of 2—Ethyl—A—ring Analogues of 19—Nor—1α,25—dihydroxy Vitamin D3

The novel 19-nor-1α,25-dihydroxy vitamin D3 analogues possessing an ethyl at the 2-position(4 and 5).were synthesized by coupling 25-hydroxy Windaus-Grundmann ketone derivative 20 with A-ring synthons(15 and 19)respectively.The enantioselective synthesis of substituted bicyclic[3,1,0]hexanes structure A-ring synthons,started from all-cis-3,5-dihydroxy-4-ethyl-1-(methoxycarbonyl)cyclohexane via lipase-catalyzd asymmetrization,was demonstratcd.     

在线二维反相色谱法快速测定维生素AD制剂中维生素A、D的含量

建立了在线二维液相色谱法快速同时测定维生素AD制剂中维生素A和D的含量。依据药典对系统适应性的要求,选择一种极性嵌合的C_(18)柱(Accucore polar premium)作为二维色谱柱,再依据疏水减法模型原理和待测样品的脂溶性特点,选择C_8柱作为一维色谱柱,一维和二维分离均采用甲醇、乙腈和水作为流动相。样品经乙醇提取后直接进样分析,采用双梯度液相色谱右泵作为一维分析泵,完成含量较高的维生素A定量及维生素D的净化;采用左泵作为二维分析泵,维生素D及前维生素D在二维色谱柱上实现分离和定量。根据维生素D在一维色谱上的出峰起止时间,确定切割时间窗口,以500μL定量环收集含有目标物的馏分,检测波长分别为264 nm和325 nm。采用外标法完成对维生素D和前维生素D的定量。整个过程在密闭系统中自动化完成。维生素A在0.1~250 mg/L,维生素D在0.02~50.0 mg/L范围内线性关系较好,相关系数(r)大于0.999;维生素D的回收率为89.9%~98.9%,连续进样的精密度和重现性的RSD分别为0.48%和1.2%,表明方法的精密度和重现性较好。     

A Non-Invasive Hair Test to Determine Vitamin D3 Levels

Vitamin D deficiency is being recognized as a global issue and has been implicated in many health issues. Hence, there is an increased interest in developing sensitive, reproducible, and non-invasive assays to measure Vitamin D levels. This study aimed to apply a sensitive liquid chromatography-mass spectrometric assay to hair samples to develop and validate a clinical assay to provide a quarterly average level of vitamin D in one test. Hair samples were collected from 70 male university students/young adults and pulverized/sonicated in methanol/water for 2 h to extract Vitamin D metabolites. A sensitive liquid chromatographic-mass spectrometric assay was employed to quantitate vitamin D and metabolites. Of the eight Vitamin D and metabolites screened, only the primary, clinically significant form of vitamin D (25OHD₃) was detected and quantified in hair samples in the range of 17–1541 pg/mg. One-third of the hair samples (21 out of 70) had Vitamin D levels below the LLOD of the assay (10 pg/mg). The mean and standard deviation values for hair (25OHD₃) were 276.7 ± 329.9, respectively. This pilot study reveals the potential of the vitamin D hair test in clinical assays as a complementary test to a vitamin D blood test, which would provide a quarterly average.     

Development and Characterization of an Orodispersible Film for Vitamin D3 Supplementation

Vitamin D plays a crucial and very well-known role in regulation of calcium homeostasis and bone metabolism and mineralization. However, a huge and more recent body of evidence supports the positive influence of vitamin D on the regulation of immune response, ranging from protection against respiratory tract infections to prevention and management of asthma. Nevertheless, vitamin D deficiency is a very common condition and there is an increasing need for suitable products for proper supplementation, allowing good compliance also in specific populations. Orally disintegrating tablets (ODT) were first developed to overcome the difficulty experienced by pediatric and geriatric patients of swallowing traditional oral dosage forms and, recently, orodispersible films (ODF) are gaining popularity as novel dosage form for assuming active pharmaceutical ingredients, vitamins, and ingredients for food supplements. This study describes a 2000 IU Vitamin D3 ODF for daily intake, consisting of hydrophilic polymers and suitable excipients, manufactured by film-casting process. Elongation-at-break (E%), Young’s modulus (Y), and tensile strength (TS) were investigated using a dynamometer. Chemical stability was evaluated assaying the vitamin D3 in the films stored at different environmental conditions. In addition, in vitro disintegration and dissolution studies were performed. Correlation existed between the mechanical properties of the film and the residual water, acting as plasticizer. The stability study showed that vitamin D3 assay was ≥90% also after 3 months at 40 °C. The film disintegrated in less than 1 min and the vitamin D3 released was ≥75% after 15 min. An ODF with suitable properties can be manufactured and used as innovative dosage form for vitamin D3 food supplements.     

Photosensitization of trans-Vitamin D3 to cis-Vitamin D3 in Heterogeneous System

Two modes of heterogeneous photoisomerization of trans-vitamin D3 to cis-vitamin D3 are described. The occurrence of isomerization on the substrate bounded to the polymeric support gives us the possibility in succession synthesis of 1α-hydroxyvitamin D3. The polymer-bound anthracene can sensitize isomerization of trans-vitamin D3 to cis-vitamin D3 efficiently and ease the separation process.     

Synthesis of Silica-anchored Sensitizer and its Application in the Preparation of Previtamin D3 from Tachysterol

A silica gel-anchored photosensitizer was synthesized with anthracene as sensitizer moiety. The photoisomerization of tachysterol to previtamin D3 was carried out with this heterogeneous photosensitizer in ethanol. The experiment results demonstrate that this solid phase photosensitizer is efficient for the photoisomerization and can be simply separated from the reaction mixture by filtration.