Analysis of Trace Arsenic using Electroadsorption Assisted Transmission X-ray Fluorescence
By
Shardrack Asare
April 21st, 2017. 1 PM
Analytical Chemistry Seminar, CP-114B
Abstract
Arsenic is a chemical element of varying importance to mankind. However, it causes arsenic poison in its inorganic form which may lead to various types of diseases including skin and nerve damage, hyperkeratosis, kidney and lung cancers. It occurs in the environment from human activities such as industrial pollution, arsenic containing pesticides and by natural means like volcanic eruptions and erosion. Humans normally get exposed to arsenic through food and ground water. Due to the health hazards of arsenic, the world health organization has limit the level of arsenic in drinking water to 10 ppb level. It is therefore imperative to develop analytical method that can effectively measure arsenic in samples at low detection limit. Classically, arsenic in drinking water has been determined using atomic absorption spectroscopy (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Whiles these methods have various advantages, sample preparation, interference and analysis time reduces the overall efficiency of these technique. A new efficient technique which is based on Electroadsorption and transmission x-ray fluorescence has been used to analyze and quantify arsenic in aqueous solution with a reported ppb limit of detection. This technique utilizes noninterference amine-functionalized carbonaceous microspheres (NH2-CMSs) as an adsorption site. Arsenic gets adsorbed onto the basic amine site of HN2-MCSs by a three-electrode set up which has positive electric field around the adsorbent. The analyte is then analyzed and quantified using X-ray fluorescence. With the Electroadsorption preconcentration, arsenic is transferred from the solution to the adsorbent very fast and this improves the limit of detection and sensitivity compared to conventional XRF. A sensitivity of 0.09 cnt/ ppb with an LOD of 7 ppb has been reported. These results showed that Electroadsorption XRF is an effective technique to determine arsenic in water with LOD levels below the WHO mark.
Reference:
- Jiang, T. J., Guo, Z., Liu, H. J. and Huang, X. J. Electroadsorption-Assisted Direct Determination of Trace Arsenic without Interference Using Transmission X‐ray Fluorescence Spectroscopy. Anal. Chem., 2015, 87, 8503−8509
- Behari, R. J., and Prakash J. Determination of total arsenic content in water by atomic absorption spectroscopy (AAS) using vapor generation assembly (VGA). Chemosphere, 2006. 63 (1), 17-21
- Choi H. S. et al. Analysis of arsenic in rice grains using ICP-MS and fs LA-ICP-MS. J. Anal. At. Spectrom., 2014, 29, 1233
Suggested reading before the seminar: http://pubs.acs.org.ezproxy.uky.edu/doi/full/10.1021/acs.analchem.5b01957