QuEChERS-高效液相色谱-串联质谱法测定酵母抽提物中9种黄色合成色素

本文建立了酵母抽提物中9种黄色合成色素的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。样品用乙腈-甲醇(5∶5,V/V)提取,经聚苯乙烯/二乙烯苯(PEP)和C18粉净化,以Zorbax Eclipse Plus C18柱(100×3.0mm,1.8μm)分离,流动相为乙腈-10mmol/L NH4Ac,梯度洗脱。采用电喷雾负离子源(ESI-)、多重反应监测(MRM)模式检测,基质匹配外标法定量。结果表明,9种黄色合成色素在各自线性范围内相关系数(r2)均大于0.994;检出限(S/N3)为0.01~0.30mg/kg,定量限(S/N10)为0.02~3.0mg/kg,3个加标水平(1、2、10倍定量限)下,回收率为75.5%~115.1%,相对标准偏差(RSD)为4.7%~17.6%。该方法适用于酵母抽提物中9种黄色合成色素的同时测定。     

LD抽运Nd∶YVO4自喇曼倍频黄光激光器

报道了LD抽运的自喇曼c切Nd∶YVO4调Q腔内倍频黄光激光器.Nd∶YVO4晶体同时作为激光介质和喇曼晶体，通过声光调Q技术，产生了1 178.7 nm的喇曼激光，经过KTP腔内倍频，输出589.4 nm黄光.测量了平均输出功率随抽运功率和脉冲重复率的变化.典型的1 066.7 nm基频光、1 178.7 nm喇曼光和589.4 nm倍频光的脉冲宽度分别为24.9 ns、11.2 ns和6.8 ns.在脉冲重复率为15 kHz，抽运功率为7.56W时，产生了平均功率为151 mW的589.4 nm光的输出.     

紫外分光光度法同时测定柠檬黄和日落黄

采用紫外分光光度法同时对饮料中柠檬黄、日落黄两种食用合成色素进行测定,确定了各色素的最大吸收波长λmax,及其最大吸收波长处的吸收系数a和摩尔吸收系数ε.结果表明:柠檬黄在λmax=426nm处的吸收系数为a=33.45 L·g-1,摩尔吸收系数为ε=1.79×104L·mol-1·cm-1.日落黄在λ=481nm处的吸收系数为a=34.00 L·g-1·cm-1,摩尔吸收系数为ε=1.54×104L·mol-1.cm-1.测定饮料中柠檬黄、日落黄含量分别为0.0067mg/mL,和0.0033mg/mL,相对标准偏差(RSD)分别为0.148%、1.026%,测定了两种色素在奥地利饮料中的回收率分别为:92.35%、96.77%.该方法操作简便,同时准确度高,精密度好.     

Cadmium Yellow Detection and Quantification by Voltammetry of Immobilized Microparticles

Cadmium pigments (cadmium sulfide and cadmium sulfoselenide) produce intense colorings such as yellow, orange and red, and are well‐known pigments in artists' colors, plastics, glasses, ceramics and enamels. This makes cadmium yellow a widespread pigment and hence is very interesting to develop a simple and fast procedure for its identification. Here we propose a straightforward procedure that is harmless to the sample allowing its application to valuable samples and also to very small samples. Three different electrochemical procedures were developed for the identification and quantification of CdS. They are based on voltammetry of immobilized microparticles that suffer a reductive scan at 60 mVs^?1 from +0.30 V to ?1.00 V producing peaks whose potential allows identification of the pigment. For quantitative purposes a pretreatment of ?1.50 V for 10 s was applied and then an oxidative scan was performed. The relative position of the Cd oxidation peak to the peak potential of an internal standard (AgCl) was used to proceed to the calibration.     

Determination of hydroxysafflor yellow A in rat plasma and tissues by high-performance liquid chromatography after oral administration of safflower extract or safflor yellow

A simple and reproducible HPLC method for quantification of hydroxysafflor yellow A (HSYA) in rat plasma and tissues after oral administration of safflower extract or safflor yellow (SY) was developed. Sample preparation was achieved by protein precipitation of plasma and tissue homogenates with three volumes of methanol. p-Hydroxybenzaldehyde was used as the internal standard (IS). HSYA and IS were separated on a Hypersil BDS-C(18) column with a gradient elution system composed of acetonitrile and aqueous acetic acid. UV detection was used at 320 nm. The calibration curves were linear in all matrices (r(2) > 0.999) in the concentration ranges 0.51-101.36 microg/mL for plasma, 12.27-2454.46 microg/g for intestines and 0.96-192.20 microg/g for lung. The intra-day and inter-day precision were all less than 12.5%, and the extract recovery was in the range 64.1-103.7% with RSD less than 15.6% for HSYA in all matrices. The method was used successfully to quantify HSYA in rat plasma and tissue samples to support a pharmacokinectic study.     

Polymerization of molecular (yellow) arsenic

DTA studies were performed to investigate the polymerization of molecular (yellow) arsenic (y-As), in the dark and also under illumination/irradiation. The semiempirical quantum chemical CNDO/BW method for calculating the dimerization reaction pathway of two As₄ molecules was applied, and showed that the stability of y-As decreases, due to the formation of stable fragments of the polymeric phase (a-As). Using the principle of orbital symmetry conservation, it was shown that polymerization takes place most favourably from a staggered “face-to-face” configuration of As₄ molecules. Dark polymerization proceeds under activation. For a result of the initial stage of polymerization, CNDO/BW simulation predicts the formation of an As₈ dimer. The molecular cluster As₈ of D_2h symmetry forms a six-membered chairshaped ring which constitutes one of the dominating units in the polymeric phase (a-As).     

红花中红花黄色素含量的反相高效液相色谱测定

本文分离纯化了红花（Carthamus tinctorius L）中Safflower yellow A，Safflomin A，Safflower yellow B，Safflomin C四种红花黄色素，并用所纯化的红花黄色素做标准品，用反相高效液相色谱法，梯度洗脱，同时测定了不同产地红花中四种红花黄色素的含量。该方的法准确度高，重现性好。     

大孔树脂吸附和分离密蒙花黄色素

本文研究了用大孔树脂吸附和分离密蒙花黄色素，比较了四种树脂对密蒙花黄色素的吸附。选用经x—5作吸附剂，洗脱剂用60％乙醇，产品质量较传统法好，提取率达8％，x－5树脂非常稳定，使用15次后其吸附率仅降低4．95％。     

氢化物发生-原子荧光光谱法测定黄磷中微量砷

采用氢化物发生-原子荧光光谱法测定黄磷中微量砷,研究了样品消化方法以及仪器工作条件、还原剂等对测定的影响,确定了最佳试验条件.在最佳试验条件下,荧光强度与砷(Ⅲ)的质量浓度在0.06～10μg·L-1范围内呈线性关系,相关系数为0.999 4,检出限为0.03μg·L-1,样品分析结果的相对标准偏差小于3.5 %,加标回收率在93.80～103.6%之间.     

黄海水体生物发光所致离水辐亮度变化及其与固有光学性质和深度的联系

利用黄海不同季节实测生物发光数据,结合同步测量的固有光学性质数据,基于辐射传输模拟,分析了生物发光所致离水辐亮度（L_w-bio）的数值变化和光谱变化,并讨论其与固有光学性质及生物发光所处深度的联系。主要结论如下：（1）黄海水体L_w-bio幅值不仅具有显著的季节变化特征,同时具有显著的空间变化特征,影响其变化的主要因素除水体本身发光生物的丰度和发光能力外,与水体自身固有光学性质和发光生物所处深度有关。（2）在光谱变化方面,L_w-bio最大峰值波长漂移不仅随着生物发光所处深度加深而增大,同时与固有光学性质有关,在固有光学性质其值较大的水体,当生物发光的光源深度位于表层以下,L_w-bio峰值波长可由蓝光波段（474 nm）变为绿光波段（最大可移动至578 nm）;在固有光学性质其值较小的清澈水体中,辐亮度光谱变化较弱,其L_w-bio峰值波长仍在蓝光波段范围内（最大可移动至500 nm）。（3）黄海海域宽泛的固有光学性质对生物发光光源的几何深度反演影响较大,但可通过L_w-bio的光谱信息,反演光源的几何深度。