Secondary abstract: |
Coagulation studies of blood hold great significance in healthcare, making it crucial to minimize the potential for errors during the pre-analytical phase that could influence the final results. In this study, we addressed an approach that would enable the straightforward determination of citrate concentration in citrate blood collection tubes within healthcare institutions, along with an assessment of whether the collection tubes comply with the specifications. Previous studies have revealed variations in citrate concentration in these tubes and the presence of impurities, primarily in the form of metallic ions such as potassium, calcium, magnesium, and lithium. However, no evaluation of the impact of additives on citrate concentration determination and the determination of metal ion concentrations in anticoagulant solutions with spectroscopic methods has been done yet. The purpose of this study was to determine sodium, potassium, calcium, magnesium, and lithium ions in a citrate medium with atomic absorption spectrometry (AAS). Additionally, we wanted to explore the potential for determining citrate concentration in citrate model solutions using molecular absorption spectrometry (MAS) in the presence of various additives (substances that could potentially be present due to the low quality of purified water, oxalate, and $K_2EDTA$). Subsequently, we intended to apply MAS and AAS methods to analyze the contents of tubes from various manufacturers. Quantitative determination of metal ions and citrate concentrations was achieved using the methods of standard additions and external standards. In assessing the effect of additives on citrate determination using the MAS method, we also included the method of the ratio of absorbances at wavelengths of 210 and 230 nm. During the experimental phase, we optimized the conditions for determining metal ion concentrations in model solutions using the AAS method. When evaluating the impact of additives on citrate determination using MAS method, we observed that nitrate anions had the most significant effect on citrate concentration determination. Subsequently, we analyzed tubes from three different manufacturers with AAS and MAS. In some tubes, in addition to sodium ions, we detected magnesium and potassium ions. The presence of magnesium ions could have been the result of leaching of magnesium from the tube stopper. The potential source of potassium ions might have been contamination with another anticoagulant during the production process. In nearly all cases, significant deviations from the defined citrate concentration were observed. Furthermore, in one type of tube, we observed an atypical shape of the molecular spectrum, the origin of which remains unexplained. The results of this study suggest that MAS method could be employed for the direct determination of citrate concentration, even in the presence of additives. By utilizing the ratio of absorbances at wavelengths of 210 and 230 nm, the presence of additives in anticoagulant solutions could be assessed. Additionally, AAS method would be suitable for the rapid determination of the concentrations of metal ions present in the citrate medium. |