Pacheco Pablo H, Olsina Roberto A, Smichowski Patricia, Martinez Luis D
Department of Analytical Chemistry, Faculty of Chemistry, Biochemistry and Pharmacy, National University of San Luis, Chacabuco and Pedernera, 5700 San Luis, Argentina.
Talanta. 2008 Jan 15;74(4):593-8. doi: 10.1016/j.talanta.2007.06.018. Epub 2007 Jun 22.
A study was undertaken to ascertain the analytical capabilities of combined ICP-OES with ultrasonic nebulization to perform on-line preconcentration and speciation of inorganic V species in urine samples using a micro-column packed with l-methionine immobilized on controlled pore glass (CPG) as solid phase extractant. At pH 5.0, l-methionine is selective only towards V(V) while, total vanadium was quantitatively adsorbed by the solid phase at pH 9.0 [as V(V)] due to V(IV) oxidation in alkali media. Vanadium species retained by l-methionine were quantitatively eluted from the column with 10% HCl. Effects of acidity, sample flow rate, concentration of eluent and interfering ions on the recovery of the analytes have been systematically investigated. The detection limit (3sigma) of V is 0.008ngmL(-1) for USN-ICP-OES with an enhancement factor of 900 (10 for USN and 90 for l-methionine), and the relative standard deviation (R.S.D.) is better than 2%. The proposed method has been applied to the determination of inorganic V(V) and V(IV) in urine.
开展了一项研究，以确定电感耦合等离子体发射光谱仪（ICP-OES）与超声雾化联用的分析能力，该联用技术使用填充有固定在可控孔径玻璃（CPG）上的L-蛋氨酸作为固相萃取剂的微柱，对尿液样本中的无机钒物种进行在线预富集和形态分析。在pH 5.0时，L-蛋氨酸仅对V（V）具有选择性，而在pH 9.0时（以V（V）形式存在），由于V（IV）在碱性介质中被氧化，总钒被固相定量吸附。被L-蛋氨酸保留的钒物种用10%盐酸从柱上定量洗脱。系统研究了酸度、样品流速、洗脱液浓度和干扰离子对分析物回收率的影响。对于超声雾化-ICP-OES，钒的检测限（3σ）为0.008 ng mL-1，增强因子为900（超声雾化的增强因子为10，L-蛋氨酸的增强因子为90），相对标准偏差（R.S.D.）优于2%。所提出的方法已应用于尿液中无机V（V）和V（IV）的测定。
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