2. Materials andmethods
2.1. Reagents and standard solutions
Hydrochloric acids, super purity (SpA) and ultra-purity (UpA) grades
were purchased from Romil. Methylmercury chloride (1000mg L−1 in
H2O) of natural isotopic composition was purchased from Strem
Chemicals and standard solutions were prepared from this stock
solution. Enriched stable Hg isotopes of 201Hg2+ and CH3
201Hg+ were
obtained as chloride solutions (10 μg g−1) from Applied Isotope
Technologies (Sunnyvale, CA, USA). Spike solutions were prepared by
an appropriate dilution of 10 μg g−1 stock solutions in 0.5% (v/v) HCl
(SpA). Sodium tetraethylborate (1%, w/v) was prepared by dissolving
NaBEt4 (Aldrich) in 2% (w/v) KOH (Merck). 2 M acetate buffer was
prepared by dissolving sodium acetate trihydrate (Sigma-Aldrich) in
ultrapure water and adjusting pH to 4.7 with glacial acetic acid
(Merck). Nitrogen, argon (99.99%) and helium (instrument He 4.6)
gases were purchased from AGA.