Separation of cations by open-tubular column liquid chromatography

Capillary ion chromatography

“…For the 4.6 lm ID PBMA column (estimated coating thickness of 0.1 lm), 100% and 89% of the theoretically expected efficiency was achieved for a 90 cm long column, with 680,000 and 246,000 plates for analytes with k 9 values of 0 and 0.16, respectively. The authors were able to separate alkali and alkaline earth metals in about 4 min and alkali metals as a group in under 90 s, reaching LODs of 0.2 -20 fmol [83]. They also showed separations of various amino acids.…”

“…Especially when used in IC, the siloxane bonds obtained with alkoxysilane chemistries [82,83] are not acceptable for practical use because of their hydrolytic instability. Recently, Pohl et al have pioneered an approach where diepoxide-amine chemistry can be used to build up a unique hydroxide selective anion exchanger layer by layer [88].…”

Gravity‐flow open tubular cation chromatography

“…Müller et al [8,9] have shown that in 2 -10 lm bore capillaries using an ion selective microelectrode as a detector, very good ionic separations are possible, attaining nearly the theoretically calculated N values. However, the preparation of such narrow bore capillary columns has been consistently arduous.…”

A weak cation-exchange phase for the separation of biogenic amines by open tubular liquid chromatography

“…In RP OT-LC, using polyacrylate stationary phases, these amines could only be separated in combination with pre-column derivatization [8]. The use of a cation-exchange layer in OT-LC has been demonstrated before by Mtiller et al [15,16]. However, serious problems were encountered during the coating of the columns.…”

“…However, serious problems were encountered during the coating of the columns. Preparation of the stationary phases by means of static coating took at least 6 weeks [15] and a dynamic coating procedure [16] was found difficult to reproduce.…”