Method for analyzing trace impurities and plasma torch used for the analysis

摘要

PROBLEM TO BE SOLVED: To provide a method for highly sensitively analyzing trace impurities included in a sample liquid obtained by diluting an organometallic compound with an inactive organic solvent, and a plasma torch for use in the analysis.SOLUTION: A plasma torch includes a plasma gas pipe, and a carrier gas pipe in the inside thereof, where a tip end of the carrier gas pipe is located at a lower part with respect to a tip end of the plasma gas pipe, and when the inside diameter of the plasma gas tube is defined as R (mm) and the length between the tip end of the plasma gas pipe and the tip end of the carrier gas pipe is defined as L (mm), the plasma torch satisfies (R/L)×100 is 20%-40%. The method for analyzing trace impurities includes: atomizing a sample liquid obtained by diluting an organometallic compound with an inactive organic solvent; then introducing the atomized sample into the plasma torch along with the carrier gas via the carrier gas pipe; and analyzing the trace impurities in the sample liquid by an inductively-coupled plasma emission spectrometry method.