Preconcentration of ultratrace rare earth elements in seawater with 8-hydroxyquinoline immobilized polyacrylonitrile hollow fiber membrane for determination by inductively coupled plasma mass spectrometry

Abstract

8-Hydroxyquinoline immobilized on polyacrylonitrile hollow fiber membrane was synthesized and used for the preconcentration of rare earth elements (REEs) and the separation of the matrix in seawater prior to their determination by inductively coupled plasma mass spectrometry (ICP-MS). Both the capacity and chemical stability of the modified polyacrylonitrile hollow fiber membrane have been evaluated. The optimum experimental conditions, such as pH, sample flow rate, volume of eluents, were investigated. The concentration of REEs in seawater and the separation of the matrix components can be achieved with a concentration factor of at least 300 times. The recommended method has been applied for the concentration and determination of REEs in coastal seawater. Results indicated that the recovery of REEs ranged from 91% to 107%, and the relative standard deviations were found to be less than 5%. A comparison was made between the REE levels determined by this method and the literature reports, and a reasonable agreement was obtained.With the widespread application of rare earth elements (REEs) in industry, agriculture, forestry and animal husbandry, much attention is now being paid to the study of REEs in the environment. However, the determination of REEs in seawater has always been a difficult task. The main restriction comes from the extremely low levels of REEs, which are below the detection limit of many instruments. Inductively coupled plasma mass spectrometry (ICP-MS) occupies an invaluable position in the modern analytical laboratory due to its excellent sensitivity, precision and accuracy. Although it is especially suitable for trace muti-element determination and is applicable to a wide range of samples, its application to the analysis of saline water remains quite limited, mainly due to the high matrix concentration (approximately 3.5%) present in seawater, which prohibits its direct analysis by ICP-MS owing to the obvious problems of salt deposition on the torch, sampling interface, or ion lenses. Therefore, the development of a preconcentration technique is an important consideration for seawater analysis.A lot of preconcentration techniques have been proposed for the determination of metals in various environmental samples. Compared with the more traditional liquid-liquid extraction methods, solid-phase techniques have become increasingly popular. It is recognized that 8-hydroxyquinoline is a well characterized organic chelation ligand, which can form covalent compounds with over 60 metal ions under controlled pH conditions, and its preference for transition and heavy metal cations over alkali and alkaline-earth cations is well known.

Effect of earthworms (Eisenia fetida) on the fractionation and bioavailability of rare earth elements in nine Chinese soils

“…115 In was added as an internal standard to monitor matrix effects and signal drifting. General instrumental operating conditions and sample digestion methods have been described previously (Wen et al, 1999). The analyses were carried out in triplicate.…”

Effect of organic acids on adsorption and desorption of rare earth elements

“…In another supporting electrolyte the concentrations of La, Ce, Pr and Nd were defined as 10.55, 26.98, 2.29 and 8.12 lg/mL, respectively. A portion of 0.500 g of soil samples were equilibrated with 20 mL of 0.01 mol/L of organic acid-0.01 mol/L of Ca(NO 3 ) 2 solutions containing REEs at the above mentioned concentration levels under the conditions of continuous shaking for 24 h. Then, the samples were centrifuged at 6000 for 0.5 h, the pH values of equilibration solutions were determined again, and the concentrations of REEs in the equilibration solutions remained were determined as well by using inductively coupled plasma mass spectrometry (ICP-MS) (Wen et al, 1999).…”

“…Indium was added as an internal standard to monitor matrix effects and signal drift. The details were reported previously by Wen et al (1999).…”

ICP-AES Detection of Ultratrace Aluminum(III) and Chromium(III) Ions with a Microcolumn Preconcentration System Using Dynamically Immobilized 8-Hydroxyquinoline on TiO2 Nanoparticles

“…21 Much research work has been done to find the most efficient way to immobilize 8-hydroxyquinoline on a number of different substrates through chemical modifications or physical adsorption procedures for the preconcentration of trace elements. [22][23][24][25] Trace element determination methods have also involved the precomplexation of analytes with a solution of the ligand, and then concentration on different adsorbents. 26,27 Among these supports, silica gel is the most often used material.…”