Analytical Methods for the Determination of Uranium in Drinking Water

4 Analytical Methods for the Determination of Uranium in Drinking Water 

The differences in sample size, sample preparation procedures, counting time, accuracy, isotope composition, and minimum detectable limits (MDL) should be noted. Some of these methods will be briefly surveyed here. The methods for determining uranium in urine are nsually also suitable for measuring the concentration of uranium in water, and those that are described in detail in Section 4.4.1 will not be discussed here to avoid duplication. 

Colorimetric Method (Photometry) A rapid, simple colorimetric method for the determination of uranium in groundwater and drinking water that can be nsed in the laboratory and in the field was described (Ratliff 2008). The first step is selectively trapping the uranium on a chromatographic resin (U/TEVA-2 in this example) followed by the formation of a colored complex with a pyridylazo indicator dye (Br-PADAP). At neutral pH, the complex absorbs light at 578 nm and is clearly visible. Qnantiflcation can be achieved with a spectrophotometer. The method can detect nraninm concentrations above the US-EPA guideline for drinking water of 30 pg L In Section 4.4.1, another colorimetric method that is snitable for the determination of nraninm in water and nrine based on the formation of a complex with Arsenazo-III is presented. 

Electroanalytical Methods Many publications described the use of electro-analytical methods for measuring uranium in water and some examples are discussed here. A detailed review article with illustrative tables that summarize the electroanalytical methods for the determination of uranium can be found elsewhere (Shrivastava et al. 2014). The tables in that review article list the method, the principles of the measurement technique, the linear range, limit of detection, tolerance to interferences (where defined), and the field in which the method is applied. 

Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES orICP-AES) This is one of the commonly deployed methods to determine the concentration of uranium in liquid samples, particularly when a multielement assay is required. A method involving solid phase extraction (SPE) on a mesoporous silica sorbent for 100-fold preconcentration of uranium and thorium from 100 mL aqueous samples prior to measurement with ICP-OES was described (Yousefi et al. 2009). Limit of detection was reported as 0.3 pg L. A slightly different approach, using octadecyl-bonded silica in the presence 2,3-dihydro-9,10-dihydroxy-l,4-anthracenedion, for preconcentration prior to ICP-OES analysis was also presented (Daneshvar et al. 2009). 

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