This paper researches DC high voltage ratios measurement method, which based on two-digital meters with external synchronous trigger mode. Through experiment, the measurement method can overcome the effect of high voltage power supply ripple and drift. The type A uncertainty of this method could decrease more than 10-100 times.
A single column separation and concentration/isotope ratio measurement method for Cr by ICP-MS (single and multicollector) was evaluated and optimized for geological and biological matrices. Results showδ53Cr homogeneity in different urban soil profiles and suggest isotopically light signature for airborne Cr emitted by steelworks.