Abstract

The Elvatech, Ltd., ElvaX (ElvaX) X-ray fluorescence (XRF) analyzer, distributed in the United States by Xcalibur XRF Services, was demonstrated under EPA’s Superfund Innovative Technology Evaluation Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recreational, and Social Park at the Kennedy Space Center on Merritt Island, Florida. The demonstration was designed to collect reliable performance and cost data for the ElvaX analyzer and seven other commercially available XRF instruments for measuring trace elements in soil and sediment. The performance and cost data were evaluated to document the relative performance of each XRF instrument.

This innovative technology verification report describes the objectives and the results of the evaluation and serves to verify the performance and cost of the ElvaX analyzer. Separate reports have been prepared for the other XRF instruments that were evaluated as part of the demonstration.

The objectives of the evaluation included determining each XRF instrument’s accuracy, precision, sample throughput, and tendency for matrix effects. To fulfill the objectives, the field demonstration incorporated the analysis of 326 prepared samples of soil and sediment that contained 13 target elements.

The prepared samples included blends of environmental samples from nine different collection sites, as well as spiked samples with certified element concentrations. Accuracy was assessed by comparing the XRF instrument’s results with data generated by a fixed laboratory (the reference laboratory). The reference laboratory performed element analysis, using:

• Acid digestion and inductively coupled plasma-atomic emission spectrometry in accordance with EPA Method 3050B/6010B
• Cold vapor atomic absorption spectroscopy for mercury only, in accordance with EPA Method 7471A

The ElvaX is a portable, bench-top, energy-dispersive XRF analyzer. It is capable of detecting elements from sodium through plutonium and can be applied in the jewelry, metallurgy, customs, forensics, medical diagnostics, food testing, and environmental testing markets. It can be used for qualitative or quantative analysis of metal alloys, liquid food, and biological samples. It can analyze liquids and powders as well as samples deposited on surfaces or filters. The system includes two primary components: an XRF spectrometer and a personal computer.

The XRF spectrometer contains a 5-watt X-ray tube excitation source with tungsten, titanium, or rhodium as the anode target material and with an adjustable 4- to 50-kilovolt power supply. The detector is a Peltier-cooled, solid-state, silicon-PiN diode with 180-electron volt resolution.

The XRF spectrometer may be set up in the field but must be in a stable environment. No portable battery systems are currently available for the ElvaX spectrometer.

A laptop computer with Microsoft Windows Millennium Edition software is used to operate the XRF spectrometer and specifically to select X-ray tube parameters, store data, and provide radiation safety. The laptop is also used to display the X-ray spectrum and to process the data. Data-processing steps include automatic peak search, overlapped peak deconvolution, background removal, automatic element identification, and background subtraction.

This report describes the results of the evaluation of the ElvaX analyzer based on the data obtained during the demonstration. The method detection limits, accuracy, and precision of the instrument for each of the 13 target analytes are presented and discussed. The cost of element analysis using the ElvaX analyzer is compiled and compared to both fixed laboratory costs and average XRF instrument costs.

Contact

Dr. Stephen Billets

See Also

Superfund Innovative Technology Evaluation

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