LC Simultaneous Determination of the Free Forms of B Group Vitamins and Vitamin C in Various Fortified Food Products

An LC–UV screening method for simultaneous determination of ascorbic acid (C), and the free forms of thiamine (B₁) riboflavin (B₂), niacin (B₃), pyridoxine (B₆) in enriched food products was developed and validated. The chromatographic separation was accomplished within 18 min using a gradient of water with 0.1% formic acid (pH 2.5) and methanol with 0.1% formic acid on a C₁₈ reverse phase column (5 μm, 150 × 3.2 mm) while detection was performed at two wavelengths (266 and 290 nm). Sample preparation was based on an extraction method originally developed for vitamin C. This procedure besides extracting vitamin C was extended to the extraction of the free forms of vitamins B₁, B_2, B_3, B₆ and B₉. The developed analytical method was successfully applied for the simultaneous determination of the vitamin C content along with the free vitamin B forms of three different enriched food products.

     

函数连接型网络应用于维生素B族四组分同时测定

报道了函数连接型网络（ＦＬＮ）用于维生素Ｂ族四组分同时测定。采用相关系数和标准偏差从原始紫外光谱数据中挑选１１个波长点供网络处理。在函数连接型网络中，非线性输入模式得到了增强，并使用了推广的δ学习规则。预测结果极行，其相关系数和标准偏差分别为０．９９９０４和０．２６８８５。     

Simultaneous Determination of Trichothecenes A, B, and D in Maize Food Products by LC–MS–MS

Two new methods of analysis, based on liquid chromatography–tandem mass spectrometry, for simultaneous determination of trichothecenes A, B, and D in maize flour and oil have been developed and validated in accordance with European Commission decision 2002/657/EC (recovery, CCα, CCβ, and precision). The trichothecenes were extracted from maize flour by matrix solid-phase dispersion, with recoveries ≥79%, and from maize oil by liquid–liquid extraction, with recoveries ≥78%. Limits of quantitation ranged between 0.03 and 50 μg kg^?1, depending on the electrospray response to each analyte and on the matrix. Monitoring of flour and oil samples with this HPLC–MS–MS method revealed the presence of deoxynivalenol, T-2 toxin, and diacetoxyscirpenol at very low concentrations.     

Simultaneous Spectrophotometric Determination of Group B Vitamins Using Parallel Factor Analysis: PARAFAC

In this work, a simple and rapid analytical procedure was applied for simultaneous determination of folic acid (vitamin B₀), thiamin (vitamin B₁), riboflavin (vitamin B₂) and pyridoxal (vitamin B₆) based on the absorbance data in the pH range 2.0‐12.0 at 25 °C using parallel factor analysis (PARAFAC). The effect of the pH as the most important factor on the sensitivity of the determination was studied. The spectral data were recorded in 400‐650 nm intervals and a 2‐12 pH range for all four vitamins. The calibration set was constructed in the concentration ranges of 4‐22, 1‐20, 6‐26, and 4‐20 μg mL^?;1 for B₆,B₂,B₁ and B₀, respectively. The root mean squares errors of prediction for the prediction set, (RMSEP), are 0.65, 0.63, 1.13 and 0.34 for B₀,B₁,B₂ and B₆, respectively. The recovery percent for the validation set are in the range of 90.6 to 107.0%. The effect of the experimental conditions and diverse species were discussed. The optimum values of these factors were searched according to the relative standard deviation of the prediction set of mixtures solutions.     

高效液相色谱法测定强化食品中维生素C的含量

建立了强化食品(饮料、奶粉、含乳饮料、大米、果泥及果冻)中维生素C含量的高效液相色谱检测方法。优化了样品处理方法,在水浴控温和避光条件下处理样品,避免维生素C被氧化。选用Tech Mate C18–ST(250 mm×4.6 mm,5μm)反相色谱柱,以0.05 mol/L磷酸二氢钾缓冲溶液(p H 3)为流动相,流量为1.0m L/min,检测器为光电二极管阵列检测器,检测波长为266 nm。线性范围为0.2~100μg/m L,相关系数为0.999 6,果泥中维生素C的定量限为20 mg/kg,其它为100 mg/kg,加标回收率为82.2%~107%,测定结果的相对标准偏差为1.23%~6.86%(n=8)。该方法简单快速,其灵敏度、准确度和精密度均能满足强化食品中维生素C的检测要求。     

Simple and Simultaneous Determination of Free Chlorine, Free Bromine and Ozone in Water by LC

A simple liquid chromatographic method has been established for the simultaneous determination of free chlorine, free bromine, and ozone generated in electrical discharges. The method is based on the formation of organic derivatives, 4-halo-2,6-dimethylphenols with 2,6-dimethylphenol (2,6-DMP). The direct substitution reaction between halogens and 2,6-DMP was used for the determination of free chlorine, free bromine and ozone in water. For the determination of ozone, iodide was added 5 min after the addition of 2,6-DMP. The detection limits were about 2.0, 3.0 and 4.0 μg L^?1 for hypochlorite, hypobromite and ozone, respectively. The method was very simple and reproducible enough to permit the simultaneous analysis of each disinfectant in surface water or sea water in the presence of the mixture of disinfectants.     

高效液相色谱法同时测定强化牛奶中的维生素A和D_2

A reversed-phase high performance liquid chromatographic method for the simultaneous determination ofvitamin A and D_2 in fortified milk has been developed. A couple of serially connected columns with μ-Bonda-pak C_(18)(300 × 3. 9mm, 10μm)and Novapak C_(18)(150 × 3. 9mm, 4μm)and methanol/water(96/4)mobile phasewere used. Vitamin A and D_2 were detected at wavelengths of 325nm and 265nm, respectively. By usingsaponification procedure, the recoveries of vitamin A and D_2 were in the range of 90～110%.     

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。     

花生及其制品中多种霉菌毒素残留同时测定方法

利用液相色谱-质谱联用（LC-MS／MS）建立了花生及其制品中多种霉菌毒素包括黄曲霉毒素（B1,B2,G1,G2）、赭曲霉毒素A、伏马毒素B1、脱氧雪腐镰刀菌烯醇、T-2毒素、HT-2毒素及玉米赤霉烯酮的同时测定方法。样品经PBS溶液和甲醇-水溶液提取,提取液经稀释、过滤后,用免疫亲和柱净化,通过淋洗去除免疫亲和柱上的杂质,随后用洗脱液过柱,将目标物分离下来,氮吹干后定容。以液相色谱-质谱／质谱测定,外标法定量。方法的检出限黄曲霉毒素B1为0．0005mg／kg,黄曲霉毒素B2,G1,G2为0．001mg／kg,赭曲霉毒素A为0．002mg／kg,伏马毒素B1为0．020mg／kg,脱氧雪腐镰刀菌烯醇为0．050mg／kg,T-2毒素为0．010mg／kg,HT-2毒素为0．010mg／kg,玉米赤霉烯酮为0．002mg／kg。在样品中添加检出限水平的毒素混标溶液,加标回收率为72．35％-97．82％,测定结果的相对标准偏差为8．95％～18．41％（n=10）.     

多壁碳纳米管修饰电极同时测定维生素B2、B6、B12和维生素C

制备了多壁碳纳米管修饰玻碳电极(MWNT/GCE),研究了维生素B2、B6、B12和维生素C共存时在该电极上的电化学行为.实验发现,在HAc-NaAc缓冲溶液中,该电极可同时测定以上四种维生素,线性范围分别为1.0×10-6～1.0×10-4 mol/L、5.0×10-5～2.0×10-3 mol/L、5.0×10-5～7.5×10-4 mol/L和5.0×10-5～2.0×10-3 mol/L,其检出限分别为7.0×10-7 mol/L、1.0×10-5 mol/L、2.5×10-5 mol/L和5.0×10-6 mol/L.样品分析的RSD分别为1.66%、1.71%、2.26%和1.46%.方法简便快捷,可用于四种维生素同时分析测定.     

高效液相色谱-串联质谱法同时测定配合饲料中维生素B_1和维生素B_2

采用高效液相色谱-串联质谱法同时测定配合饲料中维生素B1和维生素B2。样品经20mmol·L-1甲酸铵溶液提取后,采用Tigerkin C8色谱柱分离,以甲醇-20mmol·L-1甲酸溶液为流动相进行梯度洗脱,采用电喷雾正离子源-选择多反应监测模式检测,外标法定量。维生素B1和维生素B2的质量分数在20.0~500μg·kg-1范围内与其峰面积呈线性关系,检出限(3S/N)均为50μg·kg-1。对虾饲料进行加标回收试验,回收率在88.0%~120%之间,测定值的相对标准偏差(n=6)为0.90%~2.7%。方法已应用于市售配合饲料中维生素B1和维生素B2的测定。     

高效液相色谱法同时测定多种食品添加剂

 采用反相高效液相色谱法 ,一次进样、同时测定食品中的人工合成甜味剂 (糖精钠、安赛蜜、甜味素 )、防腐剂(苯甲酸、山梨酸 )、咖啡因、可可碱和茶碱。以AlltechEconosphereC18柱 (15 0mm× 4 6mmi.d .,3μm)为分离柱 ,10mmol/LNaH2 PO4 (pH 4 0 0 ) 乙腈 (体积比为 90∶10 )为流动相 ,采用二极管阵列检测器进行检测。整个分离过程在 2 3min内完成。样品平均加标回收率为 78 5 %～ 10 7 2 %。     

Simultaneous Determination of Vitamin B Complex Using Wavelet Neural Network

A simultaneous determination of four components of B‐group vitamin, using a novel wavelet‐based neural network (WNN), combined with correlation coefficient and standard deviation approach for wavelength selection, was reported in this work. Eleven representative wavelength points were selected from each original UV spectrum, based on correlation coefficients and standard deviations of the observed data. A family of wavelet basic functions built from Morlet wavelet was adopted to improve the transfer quality of output data and solve the problems of training difficultly involved in neural networks. The predicted results, with fitting correlation coefficients (R = 0.9998–0.9999) and rooted mean squares errors (RMS = 0.0578–0.1478), are satisfactory.     

石墨炉原子吸收光谱法间接测定保健食品中维生素B12

保健食品经浓硝酸-过氧化氢(10+3)混合溶液微波消解后,加入盐酸(1+99)溶液使维生素B12中的钴离子完全离解出来,再用石墨炉原子吸收光谱法测定钴离子,据此间接测定保健食品样品中维生素B12的含量.对仪器的工作条件测定波长、灯电流、载气流量作了详述,还对各种对测定有影响的因素,包括盐酸浓度、基体改进剂的种类、石墨炉的工作条件、共存离子的干扰等也作了试验并予以优化选择.维生素B12的质量分数在0.31～4.6 mg·kg-1范围内与吸光度内呈线性关系.方法检出限(3S/N)为0.093 mg·kg-1,在1.0,2.0,4.0 μg·L-1的标准加入水平下进行了回收试验和精密度试验,所得回收率在96.9%～105.0%之间.测定值的相对标准偏差(n=7)小于2.1%.     

胶束电动色谱法测定五维他口服溶液中维生素B_1、B_2、B_6、烟酰胺、泛酸钙与苯甲酸钠

建立了胶束电动色谱(MEKC)法通过波长切换同时测定五维他口服溶液中的维生素B_1、B_2、B_6、烟酰胺、泛酸钙及苯甲酸钠含量的方法,并优化了检测波长、十二烷基硫酸钠(SDS)的浓度、分离电压、缓冲液浓度及pH值等实验条件。最佳分离条件为以未涂渍的标准熔融石英毛细管柱(75μm×50 cm,有效长度42 cm)为分离通道;40 mmol/L硼酸+40 mmol/L硼砂+20 mmol/L SDS(pH 9.0)为运行缓冲液,分离电压20 kV,柱温25℃,检测波长为270 nm(维生素B_1、B_2、B_6、烟酰胺及苯甲酸钠)和200 nm(泛酸钙),电动进样10 kV、进样时间10 s。结果显示,6种化合物可在13 min内实现基线分离,且在一定质量浓度范围内线性良好,相关系数(r)不小于0.998 9;3个加标水平下的平均回收率为97.0%～103%,RSD为0.60%～1.8%。该方法快速、准确,可用于五维他口服溶液中维生素B_1、B_2、B_6、烟酰胺、泛酸钙及苯甲酸钠的含量测定。     

Simultaneous LC Analysis of Food Dyes in Soft Drinks

Liquid chromatography with diode-array detection has been used for simultaneous analysis of eight water-soluble synthetic colorants (E102, E104, E110, E122, E124, E129, E131, and E133) in non-alcoholic beverages. The colors were separated in 15 min on a C₁₈ reversed-phase column with a linear mobile phase gradient prepared from tetrabutylammonium hydrogen sulfate, methanol, and deionized water. The analytical characteristics of the separation were evaluated. Good linearity (r ² = 0.9988–0.9999), adequate limits of quantification, and high recovery (from 96.3 to 98.5%) were achieved. The method was used for analysis of 57 samples of soft drinks. The experimental results showed the colorants were present in 34 of the samples, and confirmed the method is sensitive, rapid, precise, and suitable for routine analysis of synthetic organic dyes.

     

测定四种B族维生素的流动注射-毛细管电泳联用新装置

构建了一种可连续进样、分离测定药物制剂中4种B族维生素的流动注射（FI）-毛细管电泳（CE）新装置,并优化了FI-CE条件。背景电解质（BGE）为25%乙腈-40 mmol/L硼砂（pH 9.80）,流速为0.83 mL/min,运行电压为3.3 kV(165 V/cm),FI充样时间3 s,注样时间9 s。在优化条件下,维生素B1、PP、B2和B6的线性范围分别为10~900、65~900、8~180、55~900 μg/mL,回归方程和相关系数r分别为Y=-30.8698+3.4417X(r=0.9992)、Y=193.4692+2.3783X(r=0.9980)、Y=54.6000+13.3071X(r=0.9961)和Y=143.0739+2.5705X(r=0.9977),检测限分别为5.17,7.48,1.34和6.92 μg/mL。该方法已用于维生素B1、B2、B6和复合维生素B制剂中的B1、PP、B2和B6的测定,结果令人满意。     

毛细管电泳-电化学发光/电化学检测法同时测定维生素B_1和B_6

建立了毛细管电泳-电化学发光/电化学检测(CE-ECL/EC)法同时测定维生素B1(VB1)和维生素B6(VB6)的新方法。在碱性条件下对VB1进行水解,可增强其电化学发光信号,并采用序贯均匀设计对毛细管电泳分离条件进行优化,测定VB1的电化学发光信号和VB6的电化学信号。VB1和VB6能在5min内得到良好的分离。电化学发光强度与VB1浓度在5.0~5 000.0μg/mL范围内具有良好的线性关系(r=0.997),检测限(S/N=3)为2.7μg/mL;电流强度与VB6浓度在10.0~1 000.0μg/mL范围内具有良好的线性关系(r=0.998),检测限(S/N=3)为6.8μg/mL。VB1和VB6的加标回收率范围为96.0%~100.0%,相对标准偏差为1.4%~6.7%。用建立的方法对复合VB片中的VB1和VB6进行测定,结果较好。     

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。     

链霉素、1,10-邻菲啰啉体系测定铁强化食品中铁(Ⅲ)的分光光度法研究

在pH=5.0时,采用链霉素、1,10-邻菲啰啉作为显色剂,与Fe(Ⅱ)形成三元络合物测定Fe(Ⅱ)。此方法灵敏度较高(ε=4.35×10~4L·mol~(-1)cm~(-1))。线性范围较宽(0.14μg/ml～28μg/ml)。常见离子无干扰。显色相当稳定。对铁强化醋,铁强化固体饮料中Fe(Ⅱ)进行了测定,回收率分别为93～105％和92～112％。相对标准偏差分别小于5.98％和3.88％。