Group of Analytical Chemistry, Automation, and Environment, Department of Chemistry, University of the Balearic Islands, Carreterra de Valldemossa km 7.5, 07122 Palma de Mallorca, Spain.
Anal Chem. 2012 Nov 6;84(21):9462-9. doi: 10.1021/ac302083d. Epub 2012 Oct 10.
A sensitive and selective automated in-syringe dispersive liquid-liquid microextraction (DLLME) method is presented. It was successfully applied to the determination of aluminum in coastal seawater samples. The complete analytical procedure including sampling, buffering, reaction of the analyte with fluorescence reagent lumogallion (LMG), extraction, phase separation, and quantification was completely automized and carried out within 4 min. DLLME was done using n-hexanol as an extracting solvent and ethanol as a dispersing solvent in a 1:8 v/v percent mixture. The Al-LMG complex was extracted by an organic solvent and separated from the aqueous phase within the syringe of an automated syringe pump. Two devices were specially developed for this work. These were (a) the fluorescence detector and accompanying flow cell for the organic phase enriched with the reaction product and (b) a heating device integrated into the holding coil to accelerate the slow reaction kinetics. The limits of detection (3σ) and quantification (10σ) were 8.0 ± 0.5 nmol L(-1) and 26.7 ± 1.6 nmol L(-1), respectively. The relative standard deviation for eight replicate determinations of 200 nmol L(-1) Al(3+) was <1.5%. The calibration graph using the preconcentration system was linear up to 1000 nmol L(-1) with a correlation coefficient of 0.999. Ambient concentrations of samples were quantifiable with found concentrations ranging from 43 to 142 nmol L(-1). Standard additions gave analyte recoveries from 97% to 113% proving the general applicability and adequateness of the analyzer system to real sample analysis.
一种灵敏且选择性的自动进样分散液液微萃取（DLLME）方法。该方法成功地应用于海岸海水样品中铝的测定。整个分析过程包括采样、缓冲、分析物与荧光试剂卢戈氏液（LMG）的反应、萃取、相分离和定量，完全自动化，在 4 分钟内完成。DLLME 采用正己醇作为萃取溶剂，乙醇作为分散溶剂，体积比为 1:8。Al-LMG 络合物用有机溶剂萃取，并在自动注射器泵的注射器内与水相分离。为此工作专门开发了两种装置：（a）荧光检测器和配套的流动池，用于富含有反应产物的有机相；（b）集成到保持线圈中的加热装置，以加速缓慢的反应动力学。检测限（3σ）和定量限（10σ）分别为 8.0 ± 0.5 nmol L(-1) 和 26.7 ± 1.6 nmol L(-1)。200 nmol L(-1) Al(3+) 的 8 个重复测定的相对标准偏差小于 1.5%。使用预浓缩系统的校准曲线在 1000 nmol L(-1) 以下呈线性，相关系数为 0.999。环境样品浓度可定量，发现浓度范围为 43 至 142 nmol L(-1)。标准加入法得到的分析物回收率为 97%至 113%，证明了分析仪系统对实际样品分析的通用性和适当性。
