Gradient nanopump based suppressed ion chromatography using PEEK open tubular columns

Abstract The progress of open tubular suppressed ion chromatography is reviewed from a broad perspective. Then a suppressed open tubular ion chromatography system, composed mostly of commercial components, is described: A splitless gradient-capable nanopump providing eluent delivery in the 10–1000 nL/min regime, a 7-nL injector integral to the pump, an anion exchange column based on a 25 µm i.d. poly(ether ether ketone) (PEEK) capillary, and an on-column admittance detector. The membrane suppressor was custom fabricated. Good gradient separation of seven common anions in 9 min is demonstrated using a manually prepared hydroxide eluent.