INFLUENCE OF WATER EXTRACTION METHODS FROM ENVIRONMENTAL SAMPLES ON MEASURED TRITIUM LEVEL

In order to validate the laboratory routine procedure of tritium activity concentration determination in tissue free water of environmental samples, parallel measurements were performed in water extracted from wild vegetation by two methods: azeotropic distillation and lyophilization (recommended by a French standard method). The sample humidity was established using the drying procedure to constant mass of the sample, and isotopic effect that may occur during lyophilization procedure was investigated by deuterium ratio determination in sample and extracted water. Traces of toluene in extracted water by azeotropic distillation made deuterium ration determination useless.

Smartphone-Assisted Protein to Creatinine Ratio Determination on a Single Paper-Based Analytical Device

Proteinuria is a condition in which an excessive amount of protein is excreted in urine. It is, among others, an indicator of kidney disease or risk of cardiovascular disease. Rapid and reliable diagnosis and monitoring of proteinuria is of great importance for both patients and their physicians. For that reason, a paper-based sensor for proteinuria diagnosis was designed, optimized, and validated utilizing smartphone-assisted signal acquisition. In the first step, a few commonly employed protein assays were optimized and compared in terms of analytical performance on paper matrix. The tetrabromophenol blue method was selected as the one providing a sufficiently low limit of detection (39 mg·L−1) on the one hand and appropriate long-term stability (up to 3 months) on the other hand. The optimized assay was employed for protein-to-creatinine ratio (PCR) determination on a single paper-based sensor. For both analytes the linear ranges were within the clinically relevant range. The analytical usefulness of the developed sensors was demonstrated by a PCR recovery study in artificial urine. The obtained PCR recoveries were from ca. 80 to 150%.