Determination of natural uranium and thorium in environmental samples by ETV-ICP-MS after matrix removal by on-line solid phase extraction

Abstract

An on-line solid phase extraction method has been developed for the determination of 238U and 232Th biological certified reference material using inductively coupled plasma mass spectrometry (ICP-MS ). Absolute detection limits were 2.7 pg and 3.1 pg for the determination of 238U and 232Th respectively, both being blank limited. The result for the determination of 238U in NASS-4 Open Ocean Sea Water was 2.13±0.28 ng ml−1 compared with a certified value of 2.68±0.12 ng ml−1. The results for the determination of 238U in SLRS-3 River Water was 0.043±0.002 ng ml−1 compared with an indicative value of 0.045 ng ml−1. Results for the determination of 238U and 232Th in NIST 1575 Pine Needles were 14.6±3.4 ng g−1 and 28.3±4.5 ng g−1 respectively compared with certified values of 20±4 ng g−1 and 37±3 ng g−1, using a dry and wet ashing sample preparation method. Results for the determination of 238U and 232Th in NIST 1566a oyster tissue were 121±21 ng g−1 and 29±8 ng g−1 for 238U and 232Th compared to certified and indicative values of 132±12 ng g−1 and 40 ng g−1, using the same method. When a lithium metaborate fusion method was used, results for 238U and 232Th were 23.3±2.0 ng g−1 and 36.2±5.6 ng g−1 respectively in NIST 1575 Pine Needles. The application of electrothermal vaporisation ICP-MS ( ETV-ICP-MS) to NASS-4 Open Ocean Sea Water gave 2.81±0.54 ng ml−1 and SLRS-3 River Water 0.045±0.004 ng ml−1 for 238U. When the fused NIST 1575 samples were analysed using ETV-ICP-MS, results for 238U and 232Th were 19.5±1.7 ng g−1 and 38.8±2.2 ng g−1 respectively. Absolute detection limits for ETV-ICP-MS were 30 fg and 9 fg for 238U and 232Th respectively, both being blank limited. cluded that results for the determination of 239Pu in urine were

Solid-phase extraction–spectrophotometric determination of uranium(VI) in natural waters

“…Extraction of uranium from surface or ground water has recently become of interest [1,2,3,4]. It is known to be leached out of rock and to be present in water so its concentration varies in the range of 0.1-10 µg L -1 [5].…”

Determination of U, Th and Pu in natural waters, biological materials and clinical samples by ETV-ICP-MS

“…A variety of these has been evaluated for radionuclide detection, including the cross-flow nebulizer, ultrasonic nebulizer, 25,26 desolvation systems, [26][27][28] micronebulizers 29 and electrothermal vaporization (ETV). [30][31][32][33][34][35][36][37] The use of ETV coupled to ICP-MS offers several advantages, including improved transport efficiency (20-80% in contrast to 2-5% using solution nebulization), reduced oxide and hydride formation because the solvent is largely removed, minimal sample consumption (10-100 mL), no waste production and accommodation of complex sample matrices, i.e., salts, organic matrices, solids, strong acids and slurries, with very little sample preparation. In addition, the ability to use thermal programming allows selective removal of sample matrix constituents, thereby eliminating or reducing spectroscopic interferences that would otherwise arise from the matrix.…”

Determination of uranium(VI) using Penicillium chrysogenum immobilized on silica gel and spectrophotometer

“…Due to this, several techniques have been developed for the determination of uranium including neutron activation analysis [5], molecular fluorescence spectrometry [6], gas chromatography [7] and inductively coupled plasma spectrometry [8] suffers matrix interferences.…”