Assessing the stability of Cd, Mn, Pb, Se, and total Hg in whole human blood by ICP-DRC-MS as a function of temperature and time

Storage temperatures of −20 °C and 4 °C are equivalent to −70 °C for stability of Cd, Mn, Pb, Se, and Hg in human whole blood for at least 36 months when blood is stored in sealed polypropylene vials. Increasing the sample storage temperature from −70 °C to −20 °C or 4 °C can lead to large energy savings. The best analytical results are obtained when storage time at higher temperature conditions (e.g. 23 °C and 37 °C) is minimized because recovery of Se and Hg is reduced. Blood samples stored in polypropylene cryovials also lose volume over time and develop clots at higher temperature conditions (e.g., 23 °C and 37 °C), making them unacceptable for elemental testing after 10 months and 2 months, respectively.