Buffer for Urine
Precipitates of different colours and shapes are commonly appearing in urine specimens, especially in frozen and thawed samples. The precipitates may bind large amounts of substances, especially proteins, occurring in the urine. The elimination of precipitates, using centrifugation or filtration, should be avoided as this also may remove urine components to be analysed. Buffer for Urine (Art. No. 1400) was introduced Dec 2016 and replacing Art. No. 0093 rapidly dissolves precipitates appearing in thawed urine specimens.
It has e.g. been found that up to 85% of the glycoprotein hormone erythropoietin in urine is bound to the precipitates, but can be released by the use of the UPD buffer [Lönnberg et al 2008]. This urine mixture has been used for EPO lateral flow test analysis, after desalting, or before affinity purification of urine EPO.
The UPD buffer might also be valuable for the release of several other proteins and low molecular weight substances thus making them available for analysis or further purification. A volume of 200 mL UPD is sufficient for 2 L urine.
Lönnberg, M., Drevin, M., Carlsson, J. Journal of Immunological Methods 339(2), 236-244 (2008) Ultra-sensitive immunochromatographic assay for quantitative determination of erythropoietin.