The Use of D 2 Collision Gas in Isotope Dilution for the Analysis of Se with Octopole Reaction Cell Inductively Coupled Plasma‐Mass Spectrometry

D 2 was used as a collision/reaction cell gas in Ar inductively coupled plasma‐mass spectrometry for the analysis of selenium with an isotope dilution method. In conventional H 2 collision gas, 80 [BrH] was generated by the reaction of collision gas with Br in matrix. The use of D 2 could generate 81 [BrD] instead of 80 [BrH], making it possible for the use of m / z 80, which has the highest abundance among Se isotopes. Two collision gases, H 2 and D 2 , were compared with each other for the isotope spikes of 76 Se, 77 Se, and 78 Se. For an inorganic selenium standard, both gases showed good results of 99% accuracy and below 1% Relative Standard Deviation (RSD). However, for complex‐matrix samples, the results were different. For NIST SRM 1567b (wheat flour), which had a relatively simple matrix, accuracy and precision were similar for both gases. For KRISS CRM 108‐04‐001(oyster) and NIST SRM 2976 (mussel), which had a relatively high level of Br matrix, deuterium gas showed better accuracy and precision. For H 2 , 77 Se showed the highest accuracy (98.4% recovery) but low precision (3.24% RSD). For deuterium, all three spikes showed good results, 98% average recovery and less than 1% RSD. The use of D 2 collision gas demonstrates that it is effective for the accurate determination of Se, even for a complex matrix.