高效液相色谱法测定保健食品中维生素D3的含量

目的建立用半制备型反相高效液相色谱系统纯化、正相高效液相色谱硅胶柱色谱分离测定保健食品中维生素D_3含量的方法。方法通过皂化排除样品中的干扰物质,再经乙醚萃取浓缩,将浓缩后供试品溶液注入反相高效液相色谱仪净化分离去除杂质,排除维生素A的干扰,再用正相分析色谱进行定量分析,以正己烷-正戊醇(997:3,V:V)为流动相,流速为1.0 mL/min,采用色谱柱Waters Nova-Pak?Silia分离,在254 nm检测波长下经紫外或二极管阵列检测器检测,外标法定量。结果维生素D_3浓度在0.297~9.506μg/mL范围内呈良好的线性关系,相关系数为1,平均回收率为100.55%~100.58%,相对标准偏差值为0.44%~0.72%。结论该方法快速准确,可适用于保健食品中维生素D_3含量的测定。     

正相高效液相色谱法测定鱼肝油中的维生素D3

建立一种正相高效液相色谱法测定鱼肝油中VD3含量的新方法。采用Agilent ZORBAX Rx-SIL色谱柱,以95%正己烷-5%异丙醇为流动相,流速为1.0 mL/min,PDA检测波长264 nm。结果表明:VD3浓度在0.2μg/mL～20μg/mL范围内,峰面积与含量具有良好的线性关系(r=0.999 7);平均相对标准偏差为0.62%,平均回收率为94.2%。该方法可作为鱼肝油中VD3含量的一种快速检测方法。     

液相萃取-反相高效液相色谱法联用测定植物油中的苯并芘

建立液相萃取-反相高效液相色谱法测定植物油中苯并芘的方法,以乙腈饱和的正己烷-正己烷饱和的乙腈作为萃取试剂,采用反相高效液相色谱仪对植物油中苯并芘的含量进行测定。所得线性方程Y=0.717 823X+0.159 747,相关系数r=0.999 99,线性范围在2～100 ng/m L,当乙腈饱和的正己烷与正己烷饱和的乙腈体积比为2∶5时(即4 m L乙腈饱和的正己烷,10 m L正己烷饱和的乙腈),其回收率在82.62%,精密度为1.1%,检出限为0.4μg/kg。该方法稳定、高效、检测成本低,适用于植物油中苯并芘的检测。     

反相高效液相色谱法测定维生素K2中 七烯甲萘醌的含量

目的建立维生素K2产品中七烯甲萘醌(MK-7)的反相高效液相色谱定量检测的方法。方法采用Diamonsil C18(4.6 mm×250 mm,5μm)色谱柱,流动相为50%甲醇/水(含0.1%乙酸)(95:5=V:V),50%异丙烷。流速为等速1.0 m L/min,检测波长270 nm,柱温40℃。结果 MK-7在浓度0.355~2.132 mg/m L的范围内具有良好的线性关系,相关系数在0.9999以上。重复性实验中相对标准偏差为0.41%,加标回收率为98.15%。结论此方法准确性高、重现性好、操作简单,可用于维生素K2中MK-7含量测定。     

微波辅助萃取-超高效液相色谱法快速测定纸制品中松香酸含量

建立了一个快速测定纸制品中松香酸含量的超高效液相色谱方法,该方法以甲醇为萃取溶剂,在85℃下微波萃取纸制品中的松香酸,萃取物直接进行超高效液相色谱分析,外标法定量。在S/N(信噪比)=3的条件下,该方法的检出限为0.1mg/kg,精密度为1.36%,加标平均回收率为80.00%~95.20%。该方法操作简单,灵敏度高,分析耗时只有3.5min,适用于纸制品中松香酸含量的快速测定。     

微波萃取-高效液相色谱法测定食品塑料包装材料中双酚A含量

建立了微波萃取-超高效液相色谱法(MAE-HPLC)检测塑料包装食品中双酚A的分析方法。选择甲醇为萃取溶剂,对微波萃取条件进行了优化,结果表明最佳的萃取条件为:萃取温度为80℃,萃取时间为20min。在试验选定的最佳条件下,方法线性范围0.10~20mg/L,相关系数为0.9998,方法检出限为0.1 mg/kg,样品加标回收率为88.9%~99.6%,相对标准偏差小于2.2%。     

正己烷提取-高效液相色谱法及其串联质谱法分别测定婴幼儿配方奶粉中维生素A、D3含量

目的 建立了正己烷提取、液相色谱和液相色谱串联质谱分别测定婴幼儿配方奶粉中维生素A(VA)和维生素D₃(VD₃)含量的方法。方法 样品中加入VD₃-d₃内标后皂化,正己烷提取,去离子水清洗正己烷提取液以去除提取液中的氢氧化钾,加入氯化钠促进水和正己烷两相分层,将洗至中性的正己烷提取液浓缩至干,甲醇定容至10 mL,取1 mL溶液用液相色谱法测定VA,剩余的9 mL定溶液浓缩至干后再用1 mL甲醇复容,液相色谱串联质谱测定VD₃。结果 VA的线性范围为0.2～6.0 μg/mL,方法检出限为30 μg/100g,方法定量限为100 μg/100g;VD₃的线性范围为0.01～0.20 μg/mL,方法检出限为0.5 μg/100g,方法定量限为1.0 μg/100g。通过质控样品验证方法准确度和精密度,测定值均在质控区间内,且批内相对标准偏差和批间相对标准偏差均小于5%。使用该方法成功通过了2020年婴幼儿配方奶粉中VA、VD₃样品能力验证考核。结论 该方法所用提取试剂少,且操作简单快捷,适用于婴幼儿配方奶粉中VA和VD₃的测定。     

反相高效液相色谱法测定香菜中芦丁的含量

本文建立了香菜中芦丁含量的反相高效液相色谱法的测定方法,并测定了不同采收期芦丁的含量。优选测定香菜中芦丁含量的色谱条件为：色谱柱为ODSC18分析柱（4.6mmx250mm,5μm）,流动相为甲醇-0.4%的磷酸水溶液（55：45）;DAD检测器,检测波长360nm,流速lml/min,柱温为25℃。实验结果表明,香菜中芦丁含量测定的线性回归方程为y=1064.3349x＋18.1259,r=0.9990,线性范围为0.05～0.2μg。香菜样品中芦丁平均含量为4.2551mg/g,平均回收率为96.40%（RSD=1.34%）。结果显示,本实验方法稳定、可靠,重复性好,提示可以作为香菜中芦丁含量的测定方法;不同采收期的香菜中芦丁含量略有差别。     

高效液相色谱法同时测定维生素D3和维生素K2的含量

目的建立高效液相色谱法同时测定维生素D_3和维生素K_2的含量的分析方法。方法以95%甲醇水:异丙醇=(98:2, V:V)为流动相,梯度洗脱,样品经C_(18)色谱柱(250 mm×4.6 mm, 5μm)分离,并于264 nm波长检测。结果维生素D3在浓度0.1282～1.2818μg/mL之间呈现良好的线性关系,r~2=0.9999,平均回收率为95.7%～100.7%,相对标准偏差为1.7%;维生素K_2在浓度0.51397～5.1397μg/mL之间呈现良好的线性关系,r=0.9999,平均回收率在97.3%～100.7%之间,相对标准偏差为1.3%。结论该方法操作简便、准确、重现性好,能同时测定维生素D_3和维生素K_2含量,可在实验室推广。     

固相萃取-高效液相色谱法测定饮料中维生素B12

利用AgelaPCX固相萃取柱对饮料中的维生素B12进行浓缩和净化,建立了测定饮料中维生素B12的固相萃取-高效液相色谱法。方法的线性范围为0.1～20.00μg/mL,相关系数为0.99996。方法检出限为0.2ng/mL。三个浓度水平的加标回收率分别为78.7%、83.0%、83.3%,相对标准偏差小于3%。     

The influence of latitude on the concentration of vitamin D3 and 25-hydroxy-vitamin D3 in Australian red meat

There is little information on the vitamin D content of Australian red meat or on the possible influence of latitude on this content. To determine the content of vitamin D₃ and 25-hydroxy-vitamin D₃ (25OHD₃), lamb and beef were analysed from 34° S with LC–IT-MS. To investigate the possible influence of latitude on vitamin D in meat, the lean meat and fat from five cuts of beef were analysed from 17° S and 41° S. Lamb contained 0.10 μg vitamin D₃/100 g and 0.20 μg 25OHD₃/100 g lean meat, while beef contained 0.12 μg vitamin D₃ and 0.27 μg 25OHD₃/100 g (lean meat). Latitude had no effect on the vitamin D₃ (P = 0.21) or 25OHD₃ (P = 0.29) content of lean beef, but fat from cattle in the 17° S latitude group contained significantly higher (P < 0.01) concentrations of vitamin D₃ than fat from the 41° S group of cattle.     

The determination of vitamin D3 in bovine milk by liquid chromatography mass spectrometry

A renewed international interest in vitamin D status has revealed significant deficiencies in several populations, including Australia. Vitamin D exists in two forms, cholcalciferol (D₃) and ergocalciferol (D₂). The main source of vitamin D₃ is from exposure of 7-dehydrocholesterol present in the skin to UV irradiation. However, there is an absolute requirement for vitamin D through proper dietary intake if humans live in the absence of sunlight or exclusively indoors. Bovine milk is considered to be a good dietary source of vitamin D₃, even though the levels are quite low. This paper describes robust methods using liquid chromatography–linear ion trap mass spectrometry (LC–MSⁿ) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) to measure the levels of vitamin D₃ in fresh bovine milk (0.05 μg/100 ml), commercial (natural and fortified) milk samples (0.01–2 μg/100 ml) and a dairy based infant formula (8 μg/100 g), without the need for extensive clean-up procedures. The limits of quantification (LOQ) are 0.01 μg/100 ml and 0.02 μg/100 ml for LC–MSⁿ and LC–MS/MS, respectively. Recoveries of vitamin D₃ added to the samples prior to saponification were satisfactory (range 60–90%). 25-Hydroxyvitamin D₃ was not present in any of the samples analysed (LOQ = 0.01 μg/100 ml, recovery range 30–40%).     

维生素D3羟化酶生产菌的原生质体诱变育种

原始菌株放线菌CXX-10具有维生素D325位羟化活性。通过CXX-10原生质体的制备和再生条件优化,并进行紫外诱变,获得一株酶活较原始菌株提高到152%的菌株UV-179,25(OH)D3产量达到4.27mg/L。     

Determination of vitamin K1 content in olive oil,chard and human plasma by RP-HPLC method with UV–Vis detection

The contents of phylloquinone (Vitamin K₁) were investigated in olive oil, chard and human plasma based on a reversed phase high performance liquid chromatographic method with acetonitrile/dichloromethane/methanol (60:20:20, v/v/v) as eluent in a C₁₈ μ-Bondapak column (10 μm, 300 × 3.9 mm) at 20 °C. Detection was by UV–Vis detector at 248 nm. In olive oil, the mean content of phylloquinone ranged from 12.7 to 18.9 μg/100 g, in chard ranged from 65.5 to 77.5 μg/100 g. In human plasma, phylloquinone content varied between 0.22 and 0.56 ng/ml.     

国内外维生素D2蘑菇粉食品安全相关规定研究

目前欧盟、澳大利亚、新西兰等国家和地区允许在普通食品中添加维生素D₂蘑菇粉;美国拟将维生素D₂蘑菇粉列入作为特定食品类别中的营养添加剂;中国、CAC等国家和国际组织尚未制订或公布在普通食品中添加维生素D₂蘑菇粉的法律法规与标准。本文对维生素D₂蘑菇粉生产技术与产品特点进行概述;对国内外有关维生素D₂蘑菇粉食品安全相关法律法规与标准进行梳理,为有关产品研发、食品安全监管、消费指导等提供参考。维生素D₂蘑菇粉作为一种新兴的食品原料,食品业界和食品安全监管部门应对其发展情况应予以关注;在实施产品研发、食品安全监管和制定消费指导意见时,可参考有关国家和国际组织的相关规定和标准。     

固相萃取-高效液相色谱-柱后衍生荧光法测定奶粉中维生素B11含量

建立了固相萃取-高效液相色谱-柱后衍生荧光法用于测定奶粉中维生素B11含量。奶粉酶解样液经固相萃取小柱纯化后,在ZORBAX SB-C18色谱柱上,以pH=3.5、浓度为0.05mol/L磷酸二氢钾-乙腈体系为流动相,流速为1.0mL/min,进样量20μL,以0.5%过硫酸钾溶液为衍生试剂,反应器温度为60℃,流速0.5mL/min,经荧光检测器(Ex=365nm,Em=440nm,增幅值100,衰减值16)检测定量。结果表明:在0.02～1.76μg/mL范围内该方法线性良好,R2=0.9999,检测限为4ng/mL,定量限为12ng/mL,灵敏度足以满足奶粉检测的需要,方法回收率在92.5%～95.7%之间,变异系数为1.32%。     

Sterol and vitamin D2 concentrations in cultivated and wild grown mushrooms: Effects of UV irradiation

Raw and processed mushroom samples including wild grown (chanterelles and king bolete) and cultivated samples (white and brown button, portabella, shiitake, oyster) were bought from the food market and analysed for sterols and vitamin D₂ contents. The different commercial mushrooms selected are abundant in almost every Swedish and European supermarket or outdoor market. Ergosterol was the most abundant sterol found in mushrooms present in somewhat higher concentrations in cultivated mushrooms (4.0-5.0 mg/g dry matter (d.m.)) than those found in wild mushrooms (1.7-3.5 mg/g d.m.). In addition, three closely related minor sterols, including ergosta-7,22-dienol, ergosta-5,7-dienol, and ergosta-7-enol were identified. Chanterelles and king bolete were found to be good sources of vitamin D₂ (0.7-2.2 μg/g d.m.) compared with cultivated mushrooms that had a low content (< 0.1 μg/g d.m.). Canned samples of Agaricus bisporus/white were slightly lower in ergosterol and vitamin D₂ compared to fresh samples. Irradiation with UV light in the A region (366 nm) only slightly affected ergosterol and vitamin D₂ content. In contrast, irradiation with UV light conducted in the C region (254 nm, 0-2 h, 20 cm distance) for fresh white button mushrooms and freeze-dried chanterelles resulted in nonsignificant decrease in ergosterol content, whereas vitamin D₂ increased up to 9-fold (Cantharellus tubaeformis) and 14-fold (A. bisporus/white), respectively.     

HPLC法测定小麦胚咀嚼片中维生素E

确定了高效液相快速测定小麦胚咀嚼片中维生素E含量的方法。色谱柱为反相C18柱(150mm×4.4mm),流动相为99%甲醇,检测波长为280nm,流速1.0ml/min,线性相关系数为0.999 4,检出限为0.2mg/L,重现性的相对标准偏差(RSD)为0.24%,方法的精密度RSD为1.005%,平均回收率97.8%。     

甲醇超声提取法测定保健食品中维生素A

目的 采用甲醇超声方法提取保健食品中的维生素A。用高效液相色谱法(high performance liquid chromatography, HPLC)法进行含量测定, 并与GB/T 5009.82-2016进行比较, 同时进行方法学验证。方法 样品前处理方法为甲醇超声提取法。采用C18(4.6 mm×250 mm, 5 μm)色谱柱, 甲醇为流动相, 检测波长为325 nm, 流速为1 mL/min, 柱温为30 ℃, 进样量为20 μL。结果 超声时间为5~15 min提取效率最高, 工作曲线在1.00~10.00 μg/mL范围内线性关系良好, 相关系数为0.9998, 相对标准偏差为1.82% (n=6), 平均回收率为101.09%, 方法检出限为10 μg/100 g, 定量限为31 μg/100 g。结论 和国标法相比, 本方法操作简单、准确度高, 适用于保健食品中维生素A含量的测定。     

Vitamin D3 synthesis in the entire skin surface of dairy cows despite hair coverage

How hair-coated animals such as dairy cows synthesize endogenous vitamin D₃ during exposure to summer sunlight has been unclear since vitamin D₃ and its relation to sunlight was discovered. The fur of fur-bearing animals is thought to be comparable to clothing in humans, which prevents vitamin D₃ synthesis in the skin during exposure to sunlight. Different scenarios have been suggested but never tested in cows; for example, that vitamin D₃ is synthesized from sebum on the hair and ingested by cows during grooming or that body areas such as the udder and muzzle that have scant hair exclusively produce the vitamin. To test different scenarios, 16 Danish Holstein dairy cows were subjected to 4 degrees of coverage of their bodies with fabric that prevented vitamin D₃ synthesis in the covered skin areas. The treatments were horse blanket (cows fitted with horse blankets), udder cover (cows fitted with udder covers, horse blanket + udder cover (cows fitted with both horse blankets and udder covers), and natural (cows without any coverage fitted). The cows were let out to pasture daily between 1000 and 1500 h for 4 wk in July and August 2009. Blood samples were collected 15 times during the study and analyzed for content of 25-hydroxyvitamin D₃ [25(OH)D₃] indicative of the animals’ vitamin D₃ status. Results showed that uncovered cows had a higher 25(OH)D₃ concentration in plasma after 28 d of access to sunlight compared with covered cows and that the plasma concentration of 25(OH)D₃ was strongly inversely correlated to the body surface area covered. These results are consistent with findings in humans, wherein the vitamin D₃ status of different individuals was inversely proportional to the amount of clothing worn during exposure to artificial sunlight. Hence, it appears that human clothing and cow hair are not comparable with respect to prevention of vitamin D₃ synthesis and that cows, like humans, synthesize vitamin D₃ evenly over their body surface. That vitamin D₃ should be synthesized from sebum on the hair and obtained by cows as a result of grooming is not supported by the findings in the present study either, because large differences were found between the treatment groups. If grooming were the source of vitamin D₃, then a relatively even 25(OH)D₃ concentration between treatments would be expected, because covered cows would obtain vitamin D₃ by grooming uncovered herdmates.