亲水相互作用色谱柱串联C18柱高效分析饮品中的胭脂红

建立了亲水相互作用色谱柱(HILIC)串联C18柱的方法,高效分离实际样品中的胭脂红,并对色谱柱的串联顺序以及色谱分离条件进行优化。结果表明:当HILIC柱在前C18柱在后,流动相为乙腈-乙酸铵(5 mmol/L)=91∶9(V/V),流速为0.9 mL/min,柱温为25℃,检测波长为508 nm时,此时胭脂红的分离效果最佳。在最佳的色谱分离条件下,选用两种市售饮品进行实际样品的测定,回收率在81.2%~119%。方法适用于水相样品中的强极性物质的高效分离与分析。     

气相色谱-质谱法测定纺织品中N-乙基全氟辛烷磺酰胺

提出了用气相色谱-质谱法测定纺织品中N-乙基全氟辛烷磺酰胺的方法。试样经甲醇超声提取后,在旋转蒸发仪中浓缩至5 mL,通过DB-5MS色谱柱分离,采用选择离子监测模式检测,定性离子为m/z69,108,131,169,448,定量离子为m/z108。N-乙基全氟辛烷磺酰胺的质量浓度在0.2~20.0 mg.L-1范围内与峰面积呈线性关系,检出限(3S/N)为0.69μg.L-1。用标准加入法做回收试验,测定平均回收率为97%。     

A New Capillary Electrophoresis Apparatus with Piezoelectric Ceramics High Voltage Source and Amperometric Detector

IntroductionHighperformancecapiliar}'electrophoresis(HPCE)isanewanalyticaltechnology'rapidly'developedinrecentyears.Withtheadvantagesofsmallsample.highsensitivity,highresolution.rapidanalysisandverycheaprunning,ithasbeenappliedinchemistry'.lifescienc...     

头发微量元素及钙含量测定的应用价值评价

以125例2～5岁儿童为对象，测定其全血和头发铅、锌、铁、钙含量；以全血铅、锌、铁、钙含量为标准，应用诊断试验评价方法评价头发铅、锌、铁、钙测定的应用价值。结果表明，头发铅测定的灵敏度可达88．3％，应用串联试验，头发铅测定的特异度可提高至81．8％，阳性预测值达69．6％，阴性预测值达78．8％。头发锌测定的灵敏度可达86．1％，特异度为52．4％，阳性预测值75．6％，阴性预测值为68．8％。头发铁测定的灵敏度为72．0％，特异度为77．5％，阳性预测值为83．6％，阴性预测值为63．3％，头发钙测定的灵敏度为78．9％，特异度为69．1％，阳性预测值为69．8％，阴性预测值为78．4％。锌缺乏、铁缺乏、钙缺乏，或铅负荷过高，或数种微量元素缺乏及铅中毒并存是当前严重影响儿童健康成长的常见原因。运用现代检测技术早期发现微量元素缺乏及铅中毒患儿并及时采取防治措施对促进儿童正常生长发育至关重要。头发样品容易采集、运送和保存，因此头发微量元素含量测定适合在中小城镇及农村使用。但其应用价值应进行科学评价。     

动态超声辅助萃取与HPLC联用测定淫羊藿中黄酮类化合物

建立了动态超声辅助萃取与高效液相色谱在线联用系统,用于测量淫羊藿中黄酮类化合物。萃取过程在一个循环体系中完成,萃取完成后,通过采样环采集20μL萃取液,萃取液被流动相载入色谱系统进行分离检测。4种黄酮类化合物用HPLC–MS区分,通过比较色谱峰面积选择优化萃取条件。选择50℃的水浴温度,50%的乙醇作为萃取剂,萃取剂流速为1.5 mL/min,萃取时间为8 min,样品量为15 mg。用该法测量淫羊藿样品中4种黄酮类化合物,日内、日间精密度分别为1.05%～2.05%,0.30%～3.63%(n=6)。淫羊藿中的主要化合物淫羊藿苷的加标回收率为95.2%。该方法可用于测量淫羊藿中的黄酮类化合物。     

Electro-responsive polyacrylamide-grafted-gum ghatti copolymer for transdermal drug delivery application

An application of polyacrylamide-grafted-gum ghatti (PAAm-g-GGH) copolymer for transdermal delivery of an anti-psychotic drug, quetiapine fumerate triggered by electric stimulus was explored. The electro-responsive PAAm-g-GGH was prepared by free radical polymerization underneath nitrogen atmosphere subsequent to alkaline hydrolysis. The PAAm-g-GGH was used as drug reservoir gel and crosslinked films of GGH and PVA as rate controlling membranes (RCM). The reservoir gels were uniform and translucent; pH of gels was 6.56–7.06, which is in the pH range of skin and drug content was from 89.57% to 94.51%. The thickness of RCMs was 163–227?μ; thickness was increased with increased glutaraldehyde concentration and all the RCMs were permeable to water vapors. When electric stimulus was absent, a small amount of drug was permeated from the formulations, while drug conveyance was enhanced in the existence of stimulus. Drug permeation was increased with increase in electric stimulus from 2 to 8?mA. Over two fold increase in flux was observed after application of electric stimulus. Under “on–off” electric stimulus, faster drug permeation was seen under ‘on’ condition and permeation was decreased when stimulus was ‘off.’ Histopathology study confirmed reversible alteration of skin structure under electric stimulus.     

HPLC study of tissue distribution of loganin in rats

A rapid, sensitive and selective high performance liquid chromatography (HPLC) method was developed and validated for determination of loganin in rat tissues. Samples were prepared based on a simple protein precipitation. Separation of loganin was achieved on a reversed-phase C(18) column (250 x 4.6 mm, 5 microm) with a mobile phase consisting of acetonitrile and water (16:84, v/v) at a flow rate of 1.0 mL/min. The detection wavelength was set at 236 nm and the temperature of the column was kept at 30 degrees C. The method was applied to study tissue distribution of loganin in rats after a single administration of loganin at a dose of 20 mg/kg. The highest level was observed in kidney, then in stomach, lung and small intestine. The lowest level was found in brain. The peak levels were attained at 90 min in most tissues. It was indicated that kidney was the major distribution tissue of loganin in rats, and that loganin had difficulty in crossing the blood-brain barrier. It was also found there was no long-term accumulation of loganin in rat tissues.     

乙酰丙酮分光光度法测定土壤中甲醛

建立乙酰丙酮分光光度法测定土壤中甲醛含量的分析方法。在磷酸介质中,土壤中的甲醛经过加热蒸馏提取,与乙酰丙酮反应生成黄色的二乙酰基二氢二甲基吡啶,然后于412 nm波长处测定其吸光度。甲醛含量在0.0~25μg范围内与吸光度呈良好的线性关系,线性相关系数r=0.999 6,加标回收率为76.2%~87.5%,方法检出限为0.03 mg/kg,定量限为0.12 mg/kg,测定结果的相对标准偏差为2.73%~3.68%(n=6)。该方法灵敏度高,分析速度快,适用于土壤中甲醛含量的测定。     

高温非平衡条件下氟原子亲电动力学的激波管研究

To study electron affinity kinetics, a shock tube method was applied, in which the test gas was ionized by a reflected shock wave and subsequently quenched by a strong rarefaction wave. As the quenching speed of 106 K/s was reached, a nonequilibrium ionization recombination process occurred, which was dominated by ion recombination with electrons. A Langmuir electrostatic probe was used to monitor variation in the ion number density at the reflection shock region. The working state of the probe was analyzed, and a correction was introduced for reduction of the probe current due to elastic scattering in the probe sheath. The three body electron affinity rate coefficient of the fluorine atom over the temperature range 1200 to 2200 K in an ambiance of argon gas was directly determined. The temperature dependence of electron affinity rate coefficient was discussed.     

顶空气相法测定氯乙烯生产过程产生的盐酸溶液中的乙炔和氯乙烯

 采用顶空气相法测定了氯乙烯生产过程产生的盐酸溶液中的乙炔和氯乙烯。使用氢氧化钠将试样中的氯化氢中和 ,从而消除其在气相分析乙炔和氯乙烯中的影响。顶空平衡温度为 35℃ ,平衡时间为 4 5min ,柱为填充了GDX 2 0 2固定相的 2m× 3mmi d 不锈钢柱 ,柱温 14 0℃。顶空气体进样量为 1mL。以外标法定量 ,乙炔含量测定结果的相对标准偏差为 0 85 % ;当其含量为 30 0 μg/g～ 15 0 μg/g时 ,回收率为 98 9%～10 3%。氯乙烯含量测定结果的相对标准偏差为 1 4 % ;当其含量为 2 0 0 μg/g～ 10 0 μg/g时 ,回收率为 98 8%～10 2 %。     

An epimerasic activity on galactose induced by xylose inKluyveromyces sp

Production of galactose epimerase by anKluyveromyces sp. isolated from Kefir (dairy product) was investigated in batch culture. The microorganism was cultured in media with 1% galactose, 1% xylose, or 0.5% xylose plus 0.5% galactose, in Erlenmeyer flasks shaken at 200 rpm and maintained at 30°C. After 48 h, the biomass was harvested by centrifugation and permeated with 80% ethanol. Permeated cells were suspended in 0.1M sodium phosphate buffer pH 6.5. A part of this suspension was shaken for 17h at 140 rpm. The supernatant, free of cells, was separated. Partial characterization ofKluyveromyces sp. epimerase was carried out in the cellular suspension and the supernatant solution. Enzymatic activity, using galactose as substrate, was measured. The product of this reaction was measured by the use of glucose oxidase. The results indicated: (1) there was a strong effect of xylose on induction of epimerase activity; (2) the epimerase obtained was independent of the energetic cell activity; (3) the epimerase activity in whole cells was similar to the activity obtained from the supernatant; (4) epimerase showed a typical substrate-inhibition curve and dependence on magnesium; and (5) the best pH range was between 5.5 and 6.5 and the optimal temperature was 30°C.     

蒸馏分离–电感耦合等离子体质谱法测定铜铅锌矿石中微量锗

建立蒸馏分离-电感耦合等离子体质谱法测定铜铅锌矿石中微量锗的方法。采用硝酸-磷酸混合酸消解铜铅锌矿石样品,在盐酸介质中蒸馏分离微量锗,在氦气碰撞池模式下,以103Rh为在线内标进行质谱法测定。锗的质量浓度在0~50 μg/L 范围内线性良好,相关系数为0.9995,方法检出限为0.019 μg/g。用所建方法对3个铜铅锌矿石成分国家一级标准物质进行测定,测定结果的相对标准偏差为4.58%~5.55%(n=7),样品加标回收率为93.0%~102.0%。该方法操作简便,灵敏度高,适用铜铅锌矿石中微量锗含量的测定。     

Sonochemical preparation of photochromic nanocomposite thin film based on polyoxometalates well dispersed in polyacrylamide

Novel photochromic nanocomposite thin film containing phosphotungstic acid entrapped in polyacrylamide was prepared using ultrasound technique. TEM image revealed that the polyoxometalates nanoparticles with narrow size distribution were finely dispersed in polymer matrix. IR spectra showed that the Keggin geometry of polyoxometalates was still preserved inside the composite film and strong Coulombic interaction was built between heteropolyoxometalates and polyacrylamide via hydrogen bond. It was found that the thermal stability of the hybrid film was lower than that of pure polymer but the film was stable enough for photochromic application from the TG-DTA curves. The transparent film changed from colorless to blue under UV irradiation and showed reversible photochromism. The bleaching process occurred when the film was in contact with air or O₂ in the dark. The photoreduced process was in accordance with radical mechanism.     

纳米催化剂在CO_(2)加氢制甲醇中的研究进展北大核心CSCD

为减缓温室效应,将CO_(2)转换成高附加值的甲醇是减少CO_(2)排放的有效途径,而高效催化剂是CO_(2)加氢制甲醇反应规模化的关键.可调控合成的具有量子尺寸效应的纳米催化剂在该反应上具有独特的优势.因此我们深入探讨了反应机理,综述了纳米材料在CO_(2)加氢制甲醇中的研究进展,最后给出了高效催化剂可能的发展方向.     

儿童血铅含量与智力关系的探讨

为探讨儿童智力与血铅之间的关系 ,把 30名成绩差的学生作为实验组 ,把同龄 30名成绩好的学生作为对照组 ,将两组的血铅测定值及各组血铅≥ 1 0 μg/dL的人数占总数的百分率 ,进行对照比较。结果表明 ,实验组血铅含量显著高于对照组 (P <0 0 1 ) ,且实验组高血铅的百分率也显著高于对照组 (P <0 0 1 )     

高氯酸镁吸收重量法测定铁矿石中结晶水的含量

建立了铁矿石中结晶水含量的测定方法.利用铁矿石中结晶水高温分解的特性,采用高纯氩气为载气,试样在1 000℃管式炉中加热,结晶水随载气逸出,由装有无水高氯酸镁的吸收管吸收后称量,计算出铁矿石中结晶水的含量.测定结果的相对标准偏差(RSD)小于3％(n=6),加标回收率在95％～ 104％之间.     

聚环氧乙烷凝聚重量法结合ICP–AES法测定玻璃中的二氧化硅

建立聚环氧乙烷凝聚重量法结合电感耦合等离子体发射光谱法(ICP–AES)法测定玻璃中二氧化硅的分析方法。玻璃试样经1 000℃高温下无水碳酸钠熔融,以盐酸浸出后蒸成湿盐状,再用聚环氧乙烷凝聚,过滤并将沉淀灼烧,然后用氢氟酸处理,其前后的质量差即为沉淀的二氧化硅量,滤液中的二氧化硅用ICP–AES法测定,两者相加得试样中二氧化硅的总含量。在选定的条件下,用ICP–AES法测定二氧化硅的线性范围为0.20~50μg/m L,线性相关系数为0.999 5,检出限为0.20μg/m L。测定结果的相对标准偏差为0.45%(n=6),方法的回收率在98.6%~101.9%之间。该方法具有较高的准确度和良好的精密度,测定速度快,可用于玻璃中二氧化硅含量的测定。     

甲酸在钼青铜修饰铂电极上的催化氧化

应用循环伏安法和双电位阶跃法研究了不同浓度硫酸中钼酸盐在多晶铂电极上的电化学行为 .在硫酸溶液中 ,当电位负向扫描时 ,钼酸盐即于铂电极上还原形成钼青铜 ,吸附在电极表面 ;电位正向扫描时钼青铜将再被氧化 ,氧化机理受硫酸浓度的影响 .铂电极因钼酸盐的还原和钼青铜的氧化而得到修饰 .在硫酸钠溶液中以此修饰的铂电极对甲酸氧化有明显的催化作用 ,其氧化峰电流接近未修饰铂电极上的 2倍 .钼青铜对铂的不完全修饰或过分修饰均会减弱甲酸氧化的催化作用     

柱后衍生HPLC法测定功能饮料中的牛磺酸

建立柱后衍生–高效液相色谱法测定功能性饮料中牛磺酸的含量。功能性饮料中的牛磺酸经水溶提取后与邻苯二甲醛柱后衍生,以柠檬酸三钠溶液(p H 3.2)为流动相,用AMINO–NA色谱柱分离,荧光检测器检测,激发波长为338 nm,发射波长为425 nm,柱后衍生反应温度为55℃,流量为0.4 m L/min。牛磺酸质量浓度在5.0~25.0μg/m L范围内与色谱峰面积线性关系良好,r=0.999 8,检出限(S/N=3)为0.11μg/m L,测定结果的相对标准偏差为0.73%(n=6),加标回收率在99.2%~101.6%之间。该方法灵敏度高、选择性好,可用于市售功能性饮料中牛磺酸的测定。     

高效液相色谱梯度法测定雷公藤制剂中雷公藤甲素的含量

采用高效液相色谱梯度法分离测定雷公藤制剂中雷公藤甲素的含量,用国产YWG色谱柱分离,二极管阵列检测器检测,所得三维光谱与空白光谱进行差减,取波长218nm处色谱图积分,定量。与等度法比较,梯度法具有更高的分离度、灵敏度,测定雷公藤口服液中雷公藤甲素的质量浓度为202．0μg／L,每片雷公藤片剂含甲素11．74μg,结果显著低于等度法和标示量（P<0．05）。