高效液相色谱法同时测定多维元素片中9种水溶性维生素

采用更简便的流动相体系,建立了高效液相色谱法同时测定多维元素片中9种水溶性维生素的快速分析方法。以酸水解与离心的方法处理样品,用C8柱分离,流动相A为0.1%三氟乙酸的水溶液,B为甲醇,梯度洗脱,二极管阵列检测器(DAD)检测。28min内实现了9种水溶性维生素的同时分离测定。各维生素线性关系、精密度、回收率均良好。并使用美国国家标准技术研究院(NIST)的SRM3280多维元素片标准物质对方法进行了确认,运用此法测定了市售多维元素片中的水溶性维生素含量。该法可作为维生素片剂中水溶性维生素分离测定的质控方法。     

高效液相色谱分离-在线光化学衍生/荧光光谱法测定5种水溶性维生素的研究

建立了高效液相色谱分离-在线光化学衍生/荧光光谱法测定水溶性维生素烟酸(NIA)、烟酸胺(NIC)、B1、B12及B2的新方法.以含有0.018 mol/L三乙胺、0.002 mol/L庚烷磺酸钠的0.05 mol/L磷酸盐缓冲液(A相,pH 5.8)和甲醇(B相)为流动相(85:15),等度洗脱分离5种水溶性维生素;...     

微乳液相色谱法同时分离7种水溶性维生素

采用微乳液相色谱法同时分离7种水溶性维生素(V_(B1)、V_(B2)、V_(B6)、VB_(12)、叶酸、烟酰胺和VC)。考察了微乳流动相体系中表面活性剂、油相、助表面活性剂的种类以及流动相的pH值、柱温等对水溶性维生素分离的影响。优化后微乳体系的组成为:十二烷基硫酸钠(SDS)/聚氧乙烯月桂醇醚(Brij35)/正丁醇/乙酸乙酯/水(质量比为2∶60∶66∶8∶864)。色谱柱为Agilent TC C18(250 mm×4.6 mm,5μm),柱温为30℃,检测波长为254 nm,流速为0.5mL/min。7种水溶性维生素在20 min内达到基线分离。在4~36 mg/L范围内,7种水溶性维生素的质量浓度与峰面积的相关系数均大于0.999 1。不同添加水平下,V_(B1)、V_(B2)、V_(B6)、VC和烟酰胺的平均回收率为93.9%~102.9%。该方法可用于食品和药品中的多种水溶性维生素的分离、鉴别及快速测定。     

RP-HPLC法测定SO_2处理前后新疆无核葡萄干中的B族维生素

建立了高效液相色谱同时测定SO_2处理前后无核葡萄干中4种B族维生素(V_(B1),V_(B2),V_(B3)和V_(B6))的分析方法。考察了流动相组成、p H值及梯度洗脱程序对分离效果的影响。最终采用pH 4.4缓冲溶液和乙腈作为流动相进行梯度洗脱,4种B族水溶性维生素的线性范围为0.1~20 mg/L,r20.999,检出限为0.013~0.064 mg/L,方法的平均回收率为83.0%~101.4%,相对标准偏差为0.6%~4.8%。同时利用该法对SO_2处理前后无核葡萄干中4种维生素含量的影响进行研究。结果表明,空白无核葡萄干中V_(B6)的含量最大,V_(B1)含量较低;但SO_2处理对葡萄干中V_(B1)的含量影响最大,其它3种B族维生素的含量变化不大。该方法简便,快速,准确性和重现性均较好,可用于葡萄干中B族维生素的测定。     

婴儿配方奶粉中8种水溶性维生素的高效液相色谱同时测定

采用改进后的流动相体系,建立了高效液相色谱同时测定婴儿配方奶粉中8种水溶性维生素(盐酸硫胺素、核黄素、烟酰胺、烟酸、吡哆胺、叶酸、氰钴维生素、抗坏血酸)的快速分析方法.以马尿酸作为内标,Inertsil-ODS-SP柱分离,采用含1 mmol/L七氟丁酸的磷酸二氢钾水溶液和乙腈作为流动相,梯度洗脱,紫外检测器,16 min内实现8种维生素的同时分离测定.对4种婴儿配方奶粉中的8种维生素进行测定,加标回收率在97%～105%,相对标准偏差在0.2%～2.3%.     

模式识别法用于反相液相色谱等度分离条件优化

以分离条件参数为特征变量构筑模式空间，串行指标ＨＣＲＦ为目标划分样本类别，通过主成分分析揭示模式空间的可视优化区，再由低维优化点回复到高维原始空洞，获得了最佳分离条件，此方法用于７种水溶性维生素分离，取得满意结果。     

姜黄素键合硅胶固定相HPLC分离水溶性维生素和核苷

以ODS为参比,研究了5种水溶性维生素和5种核苷在姜黄素键合硅胶固定相(CCSP)上的色谱行为,考察了甲醇、流动相pH和离子强度对CCSP分离这类极性化合物的影响,探讨了该新固定相的色谱保留机理。结果表明,在V(甲醇)∶V(0.01 mol/L NaH2PO4)=40∶60(pH 3.5)流动相体系中,5种水溶性维生素在CCSP上实现较好分离;核苷的分离则是在以纯水为流动相的条件下实现的。与ODS柱相比,在相同条件下,CCSP对5种水溶性维生素具有较高的选择性,洗脱顺序与ODS具有显著差异,且保留明显比ODS强(B6除外);与此相反,相同色谱条件下,CCSP对核苷的保留比ODS弱,CCSP可实现核苷的简便有效分离,同时胸苷与黄苷的洗脱顺序也与ODS不同。以上说明不同保留机理的存在,CCSP具有典型的反相色谱特征,但疏水性比ODS弱;极性的配体使CCSP在对溶质的分离分析中除疏水作用外,还存在n-π和π-π作用、氢键作用、偶极-偶极等作用;协同作用的结果使CCSP在水溶性极性化合物的分离分析中显示出优势。     

高效液相色谱法同时测定扁桃仁中的水溶性维生素C,B1,B2和B6

建立了用高效液相色谱同时测定扁桃仁中4种水溶性维生素C,B1,B2和B6的方法。以酸水解法处理样品,在Inertsil ODS-3柱(25 cm×4.6 mm i.d., 5.0 μm)上,以0.05 mol/L KH2PO4 (pH 6.0)-甲醇(体积比为70∶30)为流动相进行等度洗脱,检测波长265 nm条件下,对陕西蒲城扁桃仁中的水溶性维生素C,B1,B2和B6的含量进行了同时测定。4种水溶性维生素在其质量浓度为5.0~50 mg/L时线性良好(r=0.9990~0.9997);添加水平为5.0~20.0 mg/kg时,平均回收率为91.77%～99.30%,相对标准偏差(n=3)为0.31%～1.98%。测得陕西蒲城产扁桃仁中维生素B2的含量为4.27～4.53 mg/kg,维生素B1的含量为0.799～0.838 mg/kg,未检出维生素C和维生素B6。该法简便、快速,准确性和重现性均较好,对果仁中水溶性维生素的测定具有一定的参考价值。     

离子对反相高效液相色谱法同时测定复合维生素片中4种水溶性维生素

采用离子对反相高效液相色谱法同时测定了复合维生素片中烟酰胺、维生素B1、维生素B2、维生素B6等4种水溶性维生素的含量。样品经水溶解、过滤后,以Hypersil C18化学键合硅胶为固定相,以甲醇-0.5%(体积分数)醋酸水溶液(含2.5 mmol/L己磺酸钠,pH 2.8)(体积比为18∶82)为流动相,等度洗脱,紫外检测器于280 nm波长下检测。当烟酰胺、维生素B1、维生素B2和维生素B6的质量浓度分别在25450 mg/L,590 mg/L,2.590 mg/L,595 mg/L时,其峰面积与质量浓度的线性关系良好;日内测定平均相对标准偏差(n=7)分别为1.0%,2.2%,1.8%和1.3%;日间测定相对标准偏差(n=5)分别为1.5%,3.6%,2.4%和1.7%。该方法已成功应用于复合维生素片中4种水溶性维生素的同时测定。     

多种维生素的高效液相色谱分离及应用

在ＳｐｈｅｒｉｓｏｒｂＣ１８柱上，采用含Ｌｉ２ＳＯ４－己烷磺酸钠－三乙胺的水溶液作流动相，同时分离测定四种水溶性维生素：Ｂ１、Ｂ２、Ｂ６及烟酰胺。四种化合物的回收率在９９．２％～９９．９％之间，ＲＳＤ为０．１６％～０．４９％（ｎ＝５）。方法应用于常见的复合维生素药物制剂的含量测定，结果满意。     

Optimization of fat soluble vitamin separation in reversed-phase microcolumn liquid chromatography

Summary Separation behavior of fat soluble vitamins on various chemically bonded materials in non-aqueous reversedphases microcolumn liquid chromatography has been investigated. The best performance was found on a polymer-based octadecyl bonded phase. Optimization of separation for vitamins D2, D3, E and E acetate has been tried using this polymer-based column and it has been found that a binary mobile phase consisting of acetonitrile and methanol gave complete separation of fat soluble vitamins.     

Optimization of solvent selectivity for the chromatographic separation of fat-soluble vitamins using a mixture-design statistical technique

Summary A systematic approach, using a mixture-design statistical technique, has been developed for selecting the optimum mobile phase for the separation of fat-soluble vitamins in reversed-phase high-performance liquid chromatography. A quaternary mixture of methanol, acetonitrile, tetrahydrofuran and water was used as mobile phase. Retention time and peak width were recorded in ten runs augmented with five replicates and the data were subsequently fitted to special cubic polynomial models. The resulting mathematical equations enabled prediction of resolution over the entire parameter space. Contour plots of minimum effective resolution and maximum retention time as a function of mobile phase composition are presented and discussed. Visual inspection of these plots provides an overview of the quality of the separation and the analysis time required for each possible mobile-phase composition with n the parameter space. It is demonstrated that the methodology followed was an important tool which enabled the taking of informed decisions necessary for selection of the optimum mobile phase for a chromatographic separation. A combination ofR _S minimum andt _R maximum as optimization criteria in a multicriteria decision-making plot using pareto-optimality concept is discussed. This combination enabled visual demonstration of the compromise between separation quality and the economics of analysis time. Our methodology has been compared with the common used technique of ‘overlapping resolution mapping’.     

Determination of water-soluble vitamins in vitamin premixes,bioacitve dietary supplements,and pharmaceutical preparations using high-efficiency liquid chromatography with gradient elution

The influence of the pH and temperature of the mobile phase on the retention and separation of 14 vitamins and vitameric forms has been studied for four different stationary phases. The chromatographic conditions allowing the separation of 12 water-soluble vitamins and vitameric forms have been proposed. It has been established that the best separation of water-soluble vitamins can be achieved by employing gradient elution. The mobile phase A, (0.6% phosphoric acid) pH 1.5–1.8; mobile phase B, acetonitrile. For the separation of nicotinic and ascorbic acid it is preferable to use stationary phases Luna C18(2) and Gemini C18, while for the separation of riboflavin and riboflavin-5-phosphate the Synergy Hydro RP and Zorbaz SB-C18 stationary phases should be used. The selected conditions have been used for the determination of vitamins in commercial samples of vitamin preparations. The results are in good accordance with the producer data.     

Separation of water-soluble vitamins on silica modified with L-cysteine–stabilized gold nanoparticles using HPLC

Silica functionalized with 3-aminopropyltriethoxysilane and L-cysteine–stabilized gold nanoparticles has been obtained (SiO₂–NH₂–Au–L-cysteine). The influence of pH and the content of acetonitrile in the mobile phase on retention and separation selectivity of eight vitamins has been studied. The chromatographic conditions that enable the separation of C, B3, B12, B5 and B1, B2, B6, B10 mixtures of vitamins have been proposed. It has been found that it is possible to separate a mixture of vitamins C, B3, B12, and B5 in 8 min, and a mixture of vitamins B1, B2, B6, B10 in 12 min on the synthesized sorbent SiO₂–NH₂–Au–L-cysteine in isocratic elution mode.     

Development and validation of rapid ion-pair RPLC method for simultaneous determination of certain B-complex vitamins along with vitamin C

A rapid, simple, and accurate ion-pair RPLC method has been developed for simultaneous analysis of vitamin C and major B-complex vitamins. An RP C18 column thermostated at 30 degrees C was used with gradient elution of mobile phase comprising 10 mM potassium dihydrogen phosphate buffer (containing 3 mM sodium hexane-1-sulfonate, adjusted to pH 2.80 with o-phosphoric acid) and methanol at a flow rate of 1.0 mL/min to achieve the best possible separation and resolution of all vitamins in about 11.00 min. The detection was performed at 274 nm. The method has been implemented successfully for simultaneous determination of vitamins present in 12 multivitamin/multimineral pharmaceutical preparations, as well as in human urine. Typical validation characteristics were evaluated in accordance with International Conference on Harmonization guidelines. Good linearity over the investigated concentration levels was observed. Intraday repeatability was < or = 2.0%, and interday variation was < or = 2.6%, for all vitamins. The method can be used for assay of these vitamins over a wide concentration range with good precision and accuracy; hence, it would be appropriate for routine QC as well as in clinical analysis.     

Simultaneous micellar liquid chromatographic analysis of seven water-soluble vitamins: optimization using super-modified simplex

A super-modified simplex (SMS) method has been used to optimize the mobile phase used for separation of seven water-soluble vitamins in multivitamin tablets by gradient micellar liquid chromatography (MLC) with ultraviolet (UV) detection at 254, 295, and 361 nm. Effect of column temperature and addition of organic modifier to the mobile phase on separation efficiency were investigated: the appropriate conditions used were a temperature of 35 degrees C and 1-butanol modifier. The sodium dodecyl sulfate (SDS) concentration, pH, and 1-butanol% in the mobile phase were chosen for simultaneous optimization using the SMS method. The optimum mobile phase was found to be 16 mmol L(-1) (mM) SDS, 0.02 M phosphate buffer, pH 3.6, and a gradient of 3.5-10% (v/v) butanol. The total analysis time for vitamins was 75 min. The analytical parameters including linearity ( r>0.9970), limit of detection (0.12-50 micro g mL(-1)), precision of method (relative standard deviation (RSD) <8.90%), and accuracy obtained by the recovery assay (88-103%) support the usefulness of the proposed method for the determination of the water-soluble vitamins.     

Ionic liquid as a mobile phase additive in high‐performance liquid chromatography for the simultaneous determination of eleven fluorescent whitening agents in paper materials

In the present study, 11 4,4′‐diaminostilbene‐2,2′‐disulfonic acid based fluorescent whitening agents with different numbers of sulfonic acid groups were separated by using an ionic liquid as a mobile phase additive in high‐performance liquid chromatography with fluorescence detection. The effects of ionic liquid concentration, pH of mobile phase B, and composition of mobile phase A on the separation of fluorescent whitening agents were systematically investigated. The ionic liquid tetrabutylammonium tetrafluoroborate is superior to tetrabutylammomnium bromide for the separation of the fluorescent whitening agents. The optimal separation conditions were an ionic liquid concentration at 8 mM and the pH of mobile phase B at 8.5 with methanol as mobile phase A. The established method exhibited low limits of detection (0.04–0.07 ng/mL) and wide linearity ranges (0.30–20 ng/mL) with high linear correlation coefficients from 0.9994 to 0.9998. The optimized procedure was applied to analyze target analytes in paper samples with satisfactory results. Eleven target analytes were quantified, and the recoveries of spiked paper samples were in the range of 85–105% with the relative standard deviations from 2.1 to 5.1%. The obtained results indicated that the method was efficient for detection of 11 fluorescent whitening agents.     

超临界流体色谱法分析非对映异构体d4T-5’-N-磷酰化苯丙氨酸甲酯

采用超临界CO2流体色谱技术,分析d4T-5’-N-磷酰化苯丙氨酸甲酯手性磷的非对映异构体。色谱柱为Hpersil ODS2(250 mm×4.6 mm,5μm),流动相为夹带改性剂甲醇、乙醇和异丙醇的超临界CO2流体。以容量因子、选择性和分离度为指标,考察改性剂、背压和柱温对分离的影响。在甲醇、乙醇和异丙醇3种改性剂中,甲醇为最好的改性剂,其中在7%甲醇改性剂下,该化合物的分离度可达到3.35。在7%甲醇改性剂条件下,考察了压力(10～20 MPa)和温度(303.15～318.15 K)的影响。在优化的分离条件(改性剂为7%甲醇,流速为2 mL/min,柱温为308.15 K,背压为15 M Pa)下,d4T-5’-N-磷酰化苯丙氨酸甲酯的两种非对映异构体完全达到基线分离,分离时间约15 min。     

高效液相色谱法测定番泻甙及其代谢产物番泻素

采用高效液相色谱法分离测定番泻甙A和B及其代谢产物番泻素A和B,其色谱条件为：色谱柱Spherisorb C 18 不锈钢柱(250 mm×4.6 mm i.d., 10 μ m),柱温40 ℃;检测波长 360 nm;流动相A为1.25%(体积分数)乙酸水溶液,流动相B为甲醇,线性梯度程序为100%A20 min100%B。该方法快速、准确,能够对番泻甙的整个代谢过程进行实时分析。