Mesoporous titanium dioxide as a novel solid-phase extraction material for flow injection micro-column preconcentration on-line coupled with ICP-OES determination of trace metals in environmental samples

Mesoporous titanium dioxide as a novel solid-phase extraction material for flow injection micro-column preconcentration on-line coupled with ICP-OES determination of trace metals (Co, Cd, Cr, Cu, Mn, Ni, V, Ce, Dy, Eu, La and Yb) in environmental samples was described. Possessing a high adsorption capacity towards the metal ions, mesoporous titanium dioxide has found to be of great potential as an adsorbent for the preconcentration of trace metal ions in samples with complicated matrix. The experimental parameters including pH, sample flow rate, volume, elution and interfering ions on the recovery of the target analytes were investigated, and the optimal experimental conditions were established. Under the optimized operating conditions, a preconcentration time of 90 s and elution time of 18 s with enrichment factor of 10 and sampling frequency of 20 h⁻¹ were obtained. The detection limits of this method for the target elements were between 0.03 and 0.36 μg L⁻¹, and the relative standard deviations (R.S.D.s) were found to be less than 6.0% (n =7, c =5 ng mL⁻¹). The proposed method was validated using a certified reference material, and has been successfully applied for the determination of the afore mentioned trace metals in natural water samples and coal fly ash with satisfactory results.     

原位聚合阴离子交换型固相萃取（SPE）微柱

原位聚合阴离子交换型固相萃取（SPE）微柱;原位聚合;SPE微柱;分离富集     

Towards a hybrid micro-device allowing the selective detection of hydrogen fluoride vapours in a complex mixture

In this work, design and fabrication of a hybrid micro-device dedicated to the selective detection of hydrogen fluoride vapours is reported. This micro-device is composed by a gas chromatographic micro-column positioned in front of a tin dioxide-based gas sensor. The efficiency of this hybrid micro-system regarding to reproducibility and reversibility for various HF concentrations was investigated. The influence of the HF concentration on the electrical responses of the sensor is also studied. The experimental results show that this hybrid micro-system is efficient since it allows the elution, separation and detection of hydrogen fluoride at a low temperature close to ambient.     

微柱分离-ICP-MS测定高纯氧化钐中稀土杂质

研究了微柱分离 ICP MS测定高纯氧化钐中痕量Dy,Ho,Er,Tm的方法,方法基于采用Cyanex272负载树脂微柱,选定上述杂质与大量基体分离的实验条件,分离周期为32min。最终建立了微柱分离Sm后测定Dy,Ho,Er,Tm,其他稀土杂质用内标补偿ICP MS法直接测定的分析方法。方法测定下限为0.1～5.0μg·g-1,加标回收率为90%～115%,相对标准偏差为0.9%～5.1%。本法可满足快速测定99.999%氧化钐中14个稀土杂质的要求。     

Simultaneous on-line preconcentration and determination of trace metals in environmental samples using a modified nanometer-sized alumina packed micro-column by flow injection combined with ICP-OES

A novel organic reagent 3-(8-quinolinylazo)-4-hydroxybenzoic acid (QAHBA) was synthesized for chemically modified nanometer-sized alumina, and it was characterized with infrared spectrum and ¹H NMR spectra. By using modified nanometer-sized alumina as micro-column packing material, a new method of flow injection (FI) on-line preconcentration coupled to ICP-OES was developed for simultaneous determination of trace metals (Ag, Pd, Au, Ga, In and Nb) in geological and environmental samples. The effects of pH, sample flow rate, sample volume, elution and interfering ions on the recovery of the analytes have been investigated. Under the optimized operating conditions, the adsorption capacity of the modified nanometer-sized alumina for Ag, Pd, Au, Ga, In and Nb were found to be 5.1, 7.6, 17.7, 15.6, 8.1 and 12.3 mg g⁻¹, respectively. With 4 min preconcentration time and 24 s elution time, the enrichment factor was 10 and the sample frequency was 10 h⁻¹. The detection limits of this method for Ag, Pd, Au, Ga, In and Nb were 0.12, 0.44, 0.27, 0.19, 0.54 and 0.18 μg l⁻¹, respectively, while the R.S.D.s were 1.6, 2.3, 4.5, 1.6, 1.9 and 1.7% (n = 7, c = 50 ng ml⁻¹), respectively. The proposed method has been applied to the determination of these trace metals in geological-certified reference materials and natural water samples with satisfactory results.     

Analysis of Flavonoids in Silybum marianum Fruit by HPLC

Flavonoids of spotted milkweed (Silybum marianumL. Gaerth.) were optimally separated using reverse-phase HPLC with isocratic elution by CH ₃ CN-H ₂ O over Separon SGX C ₁₈ . The flavolignans silybin, silydianin, silychristin, and the flavonoid taxifolin were identified in the chromatograms of extracts from this plant     

手性微柱高效液相色谱用于对映体的分离

报道了实验室自制的手性微柱高效液相色谱系统和纤维素类手性填料的制备方法, 以及用于对映体分离的应用研究. 研究了手性微柱的装填技术并考察了影响填料性能的关键因素. 优化了流动相的组成和流速对对映体拆分的影响. 成功地分离了5种对映体. 结果表明, 该系统操作简便、分离度高, 而且流动相消耗低, 分析速度快. 该系统可以用于实验室手性分离分析.     

流动注射微柱预富集等离子体原子发射光谱法测定高纯锌中痕量稀土元素

本文报道以DCS-偶氮胂固定于活性炭上作为固定相,用于流动注射微柱预富集体系和等离子体原子发射光谱测定痕量稀土元素.测定了吸附材料对稀土元素的静态和动态吸附容量,分别达几十和几个mg/g吸附材料;对影响柱预富集的PH、上柱速度、洗脱酸度、柱尺寸等因素进行了详细考察;在优化条件下,富集倍数为10倍左右.对La、Nd、Eu、Gd、Tb、Dy、Ho和 Lu等元素的检出限为 μg/L级,RSD在 1.5％～3.9％之间(n=6,单一稀土浓度0.085 mg/L).该法应用于高纯锌中痕量稀土元素的测定,试样加入回收率在 84.5％～97.6％之间,分析结果满意.     

Graphene oxide-packed micro-column solid-phase extraction combined with flame atomic absorption spectrometry for determination of lead (II) and nickel (II) in water samples

A sensitive and simple method has been established for simultaneous preconcentration of trace amounts of Pb (II) and Ni (II) ions in water samples prior to their determination by flame atomic absorption spectrometry. This method was based on the using of a micro-column filled with graphene oxide as an adsorbent. The influences of various analytical parameters such as solution pH, adsorbent amount, eluent type and volume, flow rates of sample and eluent, and matrix ions on the recoveries of the metal ions were investigated. Using the optimum conditions, the calibration graphs were linear in the range of 7–260 and 5–85 μg L^?1 with detection limits (3S_b) of 2.1 and 1.4 μg L^?1 for lead and nickel ions, respectively. The relative standard deviation for 10 replicate determinations of 50 μg L^?1 of lead and nickel ions were 4.1% and 3.8%, respectively. The preconcentration factors were 102.5 and 95 for lead and nickel ions, respectively. The adsorption capacity of the adsorbent was also determined. The method was successfully applied to determine the trace amounts of Pb (II) and Ni (II) ions in real water samples. The validation of the method was also performed by the standard reference material.     

复合式微流控芯片上阴离子型固相萃取微柱柱性能分析

利用原位聚合法在玻璃微管道内制备阴离子交换型固相萃取(SPE)微柱,以NO2^-为分析对象,针对NaNO2-KI—Luminol发光体系设计微流控芯片,并将SPE微柱与微流控芯片连接起来组建成带有SPE微柱的复合式微流控芯片。分析了SPE微柱对NO2^-的吸附保留与富集作用,在复合式微流控芯片上,实现了NO2^-的进样、分离富集和检测,通过漏点曲线和交换容量两种方法分析了SPE微柱的柱容量。为控制SPE微柱的最大进样体积提供有利保障,并实现了食品中NO2^-的在线分离富集与检测。