Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy



Major Professor

George K. Schweitzer

Committee Members

Joseph R. Peterson


A means of analyzing 99Tc In urine by inductively coupled plasma mass spectrometry (ICP-MS) has been developed. Historically, 99Tc analysis was based on the radiometric detection of the 293 keV EMax. beta decay product by liquid scintillation or gas flow proportional counting. In a urine matrix, the analysis of 99Tc is plagued with many difficulties using conventional radiometric methods. Difficulties originate during chemical separation due to the volatile nature of Tc2O7 or during radiation detection due to color or chemical quenching. A separation scheme for 99Tc detection by ICP-MS is given and is proven to be a sensitive and robust analytical alternative. A comparison of methods using radiometric and mass quantitation of 99Tc has been conducted in water, artificial urine, and real urine matrices at activity levels between 700 and 2200 dpm/L. Liquid scintillation results based on an external standard quench correction and a quench curve correction method are compared to results obtained by ICP-MS. Each method produced accurate results, however the precision of the ICP-MS results is superior to that of liquid scintillation results. Limits of detection (LOD) for ICP-MS and liquid scintillation detection are 14.67 and 203.4 dpm/L, respectively, in a real urine matrix.

In order to determine the basis for the increased precision of the ICP-MS results, the detection sensitivity for each method is derived and measured (k vs. λ). The detection sensitivity for the 99Tc isotope by ICP-MS is 2.175 x 10-7 +/- 8.990 x 10-9 and by liquid scintillation is 7.434 x 10-14 +/- 7.461 x 10-15. A difference by seven orders of magnitude between the two detection systems allows ICP-MS samples to be analyzed for a period of 15 s compared to 3600 s by liquid scintillation counting with a lower LOD.

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