“…Ohwaki et al reported nitrogen isotope separation by using HITEC-H1 cation exchange resin (porous strong acid type, cross linking 30%, particle size 37 -77 um) and the value of HETP was 0.019 cm [7,14]. In our previous work [8][9][10], SQS-6 resin (8% cross linking, particle size 60 -80 um) was applied to nitrogen isotope separation and the value of HETP was 0.02 cm. Comparing with above mentioned HITEC-H1 and SQS-6 resin, the present resin has quite large HETPs.…”