Efficient and selective extraction of uranium from seawater based on a novel pulsed liquid chromatography radionuclide separation method

The novel pulsed liquid chromatography radionuclide separation method presented here provides a new and promising strategy for the extraction of uranium from seawater.In this study,a new chromatographic separation method was proposed,and a pulsed nuclide automated separation device was developed,alongside a new chromatographic column.The length of this chromatographic column was 10 m,with an internal warp of 3 mm and a packing size of 1 mm,while the total separation units of the column reached 12,250.The most favorable conditions for the separation of nuclides were then obtained through optimizing the separation conditions of the device:Sample pH in the column=2,sample injection flow rate=5.698 mL/min,chromatographic column heating temperature=60℃.Separation experiments were also carried out for uranium,europium,and sodium ions in mixed solutions;uranium and sodium ions in water samples from the Ganjiang River;and uranium,sodium,and magnesium ions from seawater samples.The separation factors between the different nuclei were then calculated based on the experimental data,and a formula for the separation level was derived.The experimental results showed that the separation factor in the mixed solution of uranium and europium(1:1)was 1.088,while achieving the initial separation of uranium and europium theoretically required a 47-stage separation.Considering the separation factor of 1.50for the uranium and sodium ions in water samples from the Ganjiang River,achieving the initial separation of uranium and sodium ions would have theoretically required at least a 21-stage separation.Furthermore,for the seawater sample separation experiments,the separation factor of uranium and sodium ions was 1.2885;therefore,more than 28 stages of sample separation would be required to achieve uranium extraction from seawater.The novel pulsed liquid chromatography method proposed in this study was innovative in terms of uranium separation and enrichment,while expanding the possibilities of extracting uranium from seawater through chromatography.

Adsorption separation performance of H_2/CH_4 on ETS-4 by concentration pulse chromatography

To exploit an effective adsorbent to separate hydrogen and methane, microporous titanium silicate molecular sieve NaETS-4 was synthesized and modified by strontium. The adsorption characteristics and diffusion behaviors of the prepared titanosilicate molecular sieve were studied by concentration pulse chromatography. And the effects of ion-exchange and dehydration temperature on adsorbent structure and gas diffusion were also discussed. The results showed that the thermal stability and Henry＇s Law constants were enhanced and micropore diffusivity decreased after exchanging Na＋ with Sr2＋. With the increase of dehydration temperature, Henry＇s Law constant and micropore diffusivity of CI-I4 decreased in both NaETS-4 and SrETS-4. While for 1-12 in SrETS-4, the increase of Henry＇s Law constant and the decrease of diffusion rate can be attributed to the shrinks of pore diameter resulting from the relocation of Sr2＋. Correspondingly, the kinetic selectivity of H2/CH4 reached 8.91 indicating its potentiality in separating H2 and CH4.

THEORY FOR STEP AND PULSE METHOD OF SUPERCRITICAL FLUID CHROMATOGRAPHY

The paper presents a general retention formula for supercritical fluid chromatography at finite concentration. A new chromatographic rate theory based on the fugacities of solutes instead of concentrations is developed, thus relieving the restrictions of linear isothermal distribution and infinite dilution. An expression for retention values of a N component system including solvent is obtained by combining the rate theory with the mass balance equation of solutes in chromatography. It is shown that there are N-1 characteristic retention peaks for N components and the retention time can be calculated directly from the equilibrium properties of the components in both mobile phase and stationary phase at the given conditions. The theory can be reduced to the well known formula for infinite dilution and to the result of step-pulse theory in gas chromatography under low pressure at finite concentration. Supercritical fluid chromatography may eventually prove itself to be a useful reseach tool in the field of phase equilibrium and thermodynamic properties of supercritical fluid system.

Determination of neomycin in water samples by high performance anion chromatography with pulsed amperometric detection

A simple, fast and reliable method, using high performance anion chromatography with pulsed amperometric detection, had been developed for the analysis of neomycin in water samples. The elution and separation were carried out with an isocratic mobile phase, containing 10 mmol/L NaOH. The influence of the concentration and pH of the mobile phase on the separation and detection was investigated. A quadruple-potential waveform used for the detection was optimized. The detection limit of neomycin was down to 0.027 μg/mL. The linearity of neomycin calibration curve ranged from 0.050 to 0.505 μg/mL with correlation coefficient of 0.9997. R.S.D. (n = 11) was 4.0%.

Determination of Xenon in Air by a Pulse-discharge Helium Ionization Detector

A pulse-discharge helium ionization detector（Valco, PD-D3-I） was used to measure xenon concentration in air. The dependences of the detector relative response on various gas chromatograph parameters were investigated. Based on the well prepared gas connections for the detector system and optimized gas chromatography（GC） working conditions, the atmospheric xenon concentration could be measured by the cheap GC method with a detection level of 0.7×10-9（parts by volume）. Moreover, the xenon concentration in the ground level air around our laboratory was measured with the result of 0.085×10-6（parts by volume） and RSD of 0.91%.

Optimizing the Quadruple-potential Waveform for the Determination of Gentamicin Sulfate by High Performance Liquid Chromatography with Pulsed Electrochemical Detection

In this paper, a quadruple-potential waveform was investigated and optimized for the determination of gentamicin by reversed phase ion-pair chromatography. Instead of a relatively high positive potential, a negative potential was adopted as a potential for the cleaning of gold working electrode. By this way, the formation of gold oxide resulting from the application of high positive potential during the analyte detection and electrode cleaning was greatly reduced, and therefore, the dissolution and recession of gold working electrode was also reduced. The good condition of gold working electrode achieved by this quadruple-potential waveform can help us to obtain a good reproducibility. In order to acquire signal-to-noise ratio as high as possible, several waveform parameters affecting the detection of gentamicin were carefully selected. The analytical method has been applied to the determination of two real gentamicin samples, and good results with low relative standard deviation not more than 4% were obtained.

赋能动力学色谱法快速海水提铀研究

作为重要的分离和分析手段,液相色谱法主要应用在分析化学领域,而在核素分离工作中报道十分罕见。本项目基于动力学色谱理论基础,研发出一种脉冲式进样-赋能动力学色谱柱,色谱柱的填料采用粒径为0.2 mm的惰性二氧化硅,柱长为5 m,色谱分离单元约3.06万个。通过改变色谱柱外界条件,分析铀酰离子在色谱柱内的运动情况;通过水浴加热、超声波和外加磁场对色谱柱进行赋能,以提高离子相互分离的效果;在不同进样流速和温度下,研究混合核素的分离情况,得到最佳分离条件及色谱柱的动力学特性。结果表明,样品流速为4.109 mL·min^(−1),色谱柱加热温度为50℃,此时铀酰离子和钠离子的分离因数为1.1854。以最佳分离条件进行海水提铀,得到铀和钠离子的分离因数为α=1.575,实现海水中铀和钠离子分离理论上需要20级。脉冲式进样-赋能动力学色谱柱能够高效快速地实现海水中铀的分离提取。文中采用的创新性方法,还可应用于其他核素的分离研究。

Determination of zidovudine using anion exchange chromatography with integrated pulsed amperometric detection

A rapid and practical method for direct detection of zidovudine in high performance anion exchange chromatography （HPAEC） has been developed with integrated pulsed amperometric detection （IPAD）. Dionex AS18 （250mm × 2mm） and AG18 （50 mm× 2 mm） columns and 11 mmol/L NaOH solution were used for separation. Multi-step potential waveform parameters were optimized to maximize the signal-to-noise ratio （S/N）. Utilizing an optimized waveform, the repeatability （intra-day） precision and intermediate （inter-day） precision are obtained with relative standard deviation （RSD） of 1.88, 2.27, respectively. The limit of quantification （LOQ） and limit of detection （LOD） were found to be 9.70, 3.0 ng/mL, respectively, with correlation coefficients of 0.9992 over concentration range 0.01-10 μg/mL. The present method was successfully applied to the determination of zidovudine in human plasma. The recoveries of plasma sample spiked by 0.7 μg/mL, 2.7 μg/mL obtained were 95.3-101.5%, with relative standard deviation （RSD） of 2.54%, 2.21%, respectively.

Determination of lisinopril using anion exchange chromatography with integrated pulsed amperometric detection

A rapid and practical method for direct detection of lisinopril in anion exchange chromatography（AEC） has been developed with integrated pulsed amperometric detection（IPAD）.Dionex AS 18（250 mm×2 mm） and AG 18（50 mm×2 mm） columns and 40 mmol/L NaOH solution were used for separation.Multi-step potential waveform parameters were optimized to maximize the signal-to-noise ratio（S/N）.Utilizing the optimized waveform,the repeatability（intra-day） precision and intermediate（inter-day） precision were obtained with relative standard deviation（RSD） of 0.74,0.93,respectively.The limit of quantification（LOQ） and limit of detection（LOD） were found to be 0.37,0.12ng/mL,respectively,with the correlation coefficient of 0.9998 over concentration range 0.01-1μg/mL.The present method was successfully applied to the determination of lisinopril in human plasma.The recoveries of plasma sample spiked by 0.2μg/mL,0.8μg/mL lisinopril were 98.31-103.23%with RSD of 1.41%, 0.61%,respectively.

高效离子色谱法同时测定保健食品中11种单糖和功能性低聚糖

建立保健食品中11种单糖和功能性低聚糖的高效离子色谱检测方法。样品经水提取、乙腈除杂后,经高效CarboPac PA20阴离子交换色谱柱(50 mm×2 mm,1.7μm),以水、0.2 mol/L氢氧化钠溶液和0.5 mol/L醋酸钠溶液(C)三元梯度淋洗,流速0.3 mL/min,柱温30℃,进样量25μL,使用脉冲安培检测器检测保健食品中单糖成分和功能性低聚糖。结果在最佳色谱条件下,各组分分离度良好,11种化合物在0.1∼10.0μg/mL范围内线性关系良好,相关系数均大于0.9992,方法检出限0.01∼0.03μg/mL,定量限0.03∼0.12μg/mL,标准加样回收率82.23%∼109.09%。该方法处理简单、结果准确、灵敏度高,适用于保健品中单糖和功能性低聚糖的测定。

离子色谱电化学测定牛奶中的乳糖和乳果糖

本方法成功地对牛奶中的乳糖和乳果糖进行了分离和测定。以CarboPacPA1色谱柱,5mmol/LNaOH+1mmol/LCH3COONa等梯度淋洗,脉冲安培检测,该方法具有良好的重现性、线性关系(r2>0.9989)和较低的检测限。乳糖和乳果糖的检测限分别是:0.012、0.02mg/L;样品测定的回收率为95%～102.8%。

高效阴离子交换色谱法检测酱油中的单糖及双糖

建立了高效阴离子交换色谱-脉冲安培检测法(HPAEC-PAD)测定酱油中阿拉伯糖、半乳糖、葡萄糖、蔗糖、木糖、甘露糖和果糖的方法。采用70%乙醇作为蛋白沉淀剂处理酱油样品,以Dionex CarboPacPA20阴离子交换柱为色谱柱,0.25 mol/L NaOH-水为流动相进行梯度洗脱,考察了色谱柱温度和NaOH浓度对各种糖分离的影响,确定最佳柱温为20℃,NaOH浓度为5.0 mmol/L,7种糖可在20 min内实现基线分离。7种糖的检出限(25μL进样,S/N=3)为2.0～8.0μg/L,线性范围为0.1～80 mg/L,r2大于0.999。酱油样品测定的相对标准偏差为1.4%～4.0%,加标回收率为92%～104%。该方法简便易行,灵敏度高,重现性好,适用于酱油样品中糖组分的分析。

离子色谱-积分脉冲安培检测法测定大蒜多糖的单糖组成

采用氨基酸分离柱（Amino PAC PA10，2×250mm），用10．0mmol／LNaOH溶液作为流动相，以Au为工作电极，Ag／AgCl为参比电极的脉冲积分安培离子色谱法，分离检测了大蒜多糖水解产生的单糖成分及相对含量。实验结果表明，大蒜多糖中含有半乳糖、葡萄糖、甘露醇和果糖，检出限在0．3～6μg／L范围，样品加标回收率为95％～112％。该法具有灵敏度高、精密度好、分离效果好和样品不需要衍生处理的优点，适用于各种植物多糖的单糖组成分析。

离子色谱法测定饱和卤水中痕量碘离子

建立了一种在线样品预处理、脉冲安培检测饱和卤水中痕量I^-的离子色谱新方法。进样体积为50止，选用CryptandC1浓缩柱富集I^-，并用10mmol／L NaOH洗脱样品中的基体Cl^-。用0．5mmol／LNaOH将I^-从浓缩柱转移到保护柱柱端。用IonPac AS20阴离子交换柱，25mmol／L NaOH淋洗分离，结合脉冲安培银工作电极检测。I^-检出限为0．07μg／L（3倍基线噪音）；I^-在5～1000μg／L范围内具有良好的线性关系（r=0．9995）。50μg／L的I^-溶液连续进样9次，峰高相对标准偏差（RSD）为1．0％。

离子色谱法检测蜂蜜和葡萄酒中的蔗糖、葡萄糖和果糖

建立离子色谱法同时分离检测蜂蜜和葡萄酒中的蔗糖、葡萄糖和果糖的分析方法。用METROSEPCARB1(150mm×4.0mm)阴离子交换分离柱和脉冲安培检测器,对淋洗分离条件进行优化。选择10mmol/LNaOH为淋洗液,淋洗液流速1.0mL/min,总分析时间25min。蔗糖、葡萄糖、果糖的检测限分别为0.085、0.126、1.072mg/L(进样体积20μL)。混标溶液连续8次进样,峰高的相对标准偏差为3.12%～10.56%,保留时间的相对标准偏差为2.36%～3.25%。样品测定的回收率为90.0%～99.5%。该方法具有样品前处理简单,灵敏度高,快速有效等优点,可为蜂蜜和葡萄酒质量检测提供一个简单有效的方法。

离子色谱法检测水果、饮品中的蔗糖、葡萄糖和果糖

建立离子色谱法同时分离检测两种水果和两种饮品中的蔗糖、葡萄糖和果糖的分析方法。采用METROSEPCARB 1(150mm×4.0mm)阴离子交换分离柱和脉冲安培检测器,对淋洗分离条件进行优化。确定柱温20℃、淋洗液30mmol/L NaOH溶液,淋洗液流速1.0mL/min,总分析时间25min。在1.0～50.0mg/L范围内蔗糖、葡萄糖和果糖分别呈良好线性。在优化的分离条件下,蔗糖、葡萄糖和果糖的检出限分别为0.085、0.126mg/L和1.072mg/L(进样体积20μL,峰面积定量)。用8.0mg/L蔗糖、葡萄糖和果糖的混标溶液连续5次进样,3种糖峰面积的相对标准偏差分别为6.09%、2.90%和3.03%,保留时间的相对标准偏差分别为2.49%、1.78%和1.79%。样品测定的回收率为83.4%～126.6%。用该方法检测了水果和饮品中的3种糖,效果良好。同时具有操作简单,结果准确,快速有效等优点,可为水果和饮品质量检测提供一个简单有效的方法。

离子色谱法同时测定烟草中6种糖

利用离子色谱法同时测定烟草中鼠李糖、葡萄糖、木糖、果糖、蔗糖和麦芽糖。采用超声浸提烟草中的糖,经Metrosep Carb 1阴离子交换柱分离,以0.100mol·L-1氢氧化钠溶液为淋洗液,采用脉冲安培检测器检测。6种糖的浓度在一定范围内与峰面积呈线性关系,方法的检出限在0.012~0.055mg·L-1之间。样品回收率在92.6%~105%之间,测定值的相对标准偏差(n=6)在0.6%~2.0%之间。方法用于快速分析烤烟的上、中、下部中6种糖的含量。

液相色谱-脉冲安培电化学法测定硫酸阿米卡星注射液中主要组分和杂质

建立了一种新的用反相离子对液相色谱(LC)分离、以金电极为工作电极的脉冲安培电化学法(PAD)直接检测硫酸阿米卡星注射液中主要组分及杂质含量的分析方法.流动相为0.033mol·L-1草酸、0.012mol·L-1七氟丁酸、108ml·L-1乙腈,用稀NaOH调节pH至3.4.考察了各色谱参数对分离测定的影响.实验证明,该方法不需要衍生化,可直接检测硫酸阿米卡星.与报道的其他方法相比,该方法不仅能使硫酸阿米卡星注射液中的主要组分阿米卡星和杂质组分卡那霉素A得到了很好的分离,还分离出了其它一些未能确证的组分.可望今后用质谱法等对未知组分进行确证后,对硫酸阿米卡星原料药、注射液等实际样品中的各组分进行测定.

离子色谱法测定化妆品中的海藻糖

建立了一种高效阴离子交换-脉冲安培检测(HPAE-PAD)测定化妆品中海藻糖的方法。采用不同的样品前处理方法,用METROSEP CARB 1分离柱(150 mm×4.0 mm)进行分离,以200.0 mmol·L-1的NaOH溶液为流动相进行洗脱,7 min内可完成对样品的分析。结果表明,海藻糖的检出限为0.02 mg·L-1,峰面积的相对标准偏差为0.17%,保留时间的相对标准偏差为0.28%;化妆品中常见的甘油和丙二醇不会对其测定产生干扰,平均回收率为95.2%～99.2%。

离子色谱-脉冲安培检测器分析饮料中单糖和二糖

建立了等度离子色谱-脉冲安培检测分析饮料中葡萄糖、果糖、蔗糖和乳糖的方法。采用CarboPacPA10分离柱对分离条件进行了优化,确定柱温为30℃、淋洗液为52mmol.L-1的NaOH溶液,在0.10—20.0mg.L-1范围内葡萄糖、果糖、蔗糖、乳糖呈良好线性,回收率分别为93.3%—112.5%、102.2%—111.6%、96.8%—99.6%、88.0%—102.6%,检出限分别为0.8、4.0、5.0、10.0mg.kg-1,精密度分别为0.18%—1.21%、0.53%—3.76%、0.65%—2.54%、1.65%—5.11%。检测了饮料中的单糖和二糖,效果良好。