Analytical programs, precalibrated

XRF nowadays provides accurate concentration data at major and low trace levels for nearly all the elements in a wide variety of materials. Hardware and software advances enable on-line application of the fundamental approach in either classical or influence coefficient algorithms for the correction of absorption and enhancement effects. Vendors software packages, such as QuantAS (ARL), SSQ (Siemens), X40, IQ+ and SuperQ (Philips), are precalibrated analytical programs, allowing semiquantitative to quantitative analysis for elements in any type of (unknown) material measured on a specific X-ray spectrometer without standards or specific calibrations. The basis is the fundamental parameter method for calculation of correction coefficients for matrix elements (inter-element influences) from fundamental physical values such as absorption and secondary fluorescence. UniQuant (ODS) calibrates instrumental sensitivity factors (k values) for 79 elements with a set of standards of the pure element. In this approach to inter-element effects, it is not necessary to determine a calibration curve for each element in a matrix. Calibration of k values with pure standards may still lead to systematic errors for unknown polymer samples. UniQuant provides semiquantitative XRF analysis [242]. 

In recent years, there has been an increase in the number of XRF users asking for precalibrated analytical program packages. The general requirement is to start to analyze immediately after installation of the XRF system in order to... 

An important request for such precalibrated analytical programs of the supplier is the delivery of a complete package containing measurement conditions, matrix corrections and line overlap factors as well as the sample material necessary for installation and drift correction. 

A further example of new precalibrated analytical programs are the Geo-Quant programs, for an exact quantitative analysis of geological materials, e.g. soils, rocks, minerals, ores, fly ashes, slags, filter cakes or cement samples. 

X-ray fluorescence analysis is principally a relative method, as the spectrometer only provides intensities of fluorescence lines. Therefore, standard samples with exactly defined and certified concentration values are required in order to fix the relation between measured intensity and concentration in the sample. Since spectrometers of the same type differ only in their sensitivity (pulse rate per %), the standard samples can be measured and evaluated at the manufacturer s site - keeping in mind the required analytical precision. Transfer of these values to the user s specific x-ray system and compensation of the system drift can be done by using the reference samples which are provided with the software package of the precalibrated programs. 

Only in recent years have such universal analytical solutions been developed for XRF analysis. Even if there is still a large development potential for the future to be found in these programs, for example the precalibrated MetalQuant program for effective quantitative XRF analysis of different elements in iron, copper, nickel, cobalt and aluminum based alloys, most users already appreciate them. 

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