Mercury-202 spike in a chlorine-water solution
 G. Audi and A.H. Wapstra, The 1993 atomic mass evaluation, Nucl Phys A565 (1993) 1-65.
 A. Dobney, Preparation of a mercury spike reference material (IRMM-640) (1997)
The Spike Isotopic Reference Material IRMM-640 comes in a flame-sealed quartz ampoule containing about 75 nmol mercury in 5 ml of a chemically stable hydrochloric acid solution.
The molarity is about 0.5 M HCl.