A radiometric method for the determination of manganese, based on the exchange reaction between*Zn-EDTA and Mn in the presence of PAN has been developed. The Zn-PAN complex formed due to exchange, was proportional to Mn content. When the complex was extracted into chloroform from ammonia-ammonium chloride buffers, at pH 8.5, 4-50μg Mn could be determined. Effect of diverse ions on the exchange has also been studied.
Determination of iron (II) by radiochemical displacement of65Zn from Zn-PAN has been studied. pH 5.5 in borate buffers was suitable for the quantitative displacement. Interference due to diverse metal ions has also been reported.
Self irradiation of the CaSO4: Tm-TLD (National UD-200S), a commercial thermoluminescense dosimeter (TLD) of high sensitivity, was measured by keeping 10 samples taken from each of 10 batches of the TLD in a lead brick enclosure located underground for 20 days. In one batch was observed a very high self-irradiation of 186±26 fA/kg (2.6±0.36μR/h), which was about 3 times as large as for the other 9 batches. The source of this high self irradiation was investigated by the analysis of variance and identified to be the cap of the holder of thermoluminescent detectors which incorporates the Sn-Pb alloy filter for the energy compensation.
Usefulness of three kinds of TSH kits by immunoradiometric assay (IRMA) was evaluated. They were able to measure low levels (less than 0.1 μIU/ml) in serum thyroid stimulating hormone (TSH) with incubation of short time (4 hours) . In particular, RIABEAD II kit had a highly specific affinity for TSH and the normal range (±2 S.D.) using it showed from 0.20 to 3.50 μIU/ml in 150 normal subjects. In patients with hyperthyroidism and in patients with hypothyroidism, the values of TSH were lower and higher than those of normal subjects, respectively. Another kits showed similar results. These results indicate that these TSH-IRMA kits are useful to evaluate serum TSH levels exactly.