Aromatic bases as eluent components for conductivity and indirect ultraviolet absorption detection of inorganic cations in nonsuppressed ion chromatography

Abstract

1435sorption bands a t 276 and 338 nm have nearly identical absorptivities but are derived from optical transitions to two entirely different excited electronic states. Although the experimental error associated with the extremely weak fluorescence and phosphorescence emissions obtained by using 276 nm excitation are quite large, the near identity of the IplIf ratios shown in Figure 5b indicate that, as expected, rapid interconversion between the excited singlet states of pyrene prevails leaving the phosphorescence quantum yield insensitive to the fact that the excited singlet states resulting from excitation at 276 and 338 nm are different. LITERATURE CITEDKalyanasundram, K.; Grieser, F.; Thomas, J. K. Chem. fhys. Lett. Humphry-Baker, R.; Moroi. Y.; Gratzei, M. Chem. fhys. Lett. 1978, Turro, N. J.; Llu, K.-C.; Chow, M.-F.; Lee, P. fhotochem. fhotobiol. 1978, 27, 523-529. Almgren, M.; Grieser, F.; Thomas, J. K.A range of protonated aromatlc bases was Investigated as eluents for the nonsuppressed Ion chromatography of lnorganlc cations, uslng simultaneous dlrect conductlvlty and Indirect UV absorption detectlon. When a low-capaclty sty-rene4lvlnylbenzene cation-exchange column was used, m e thylpyrldlne Isomers, dlmethylpyridlne Isomers, benzylamlne, 2ghenylethylamlne, and 4-methylbenrylamlne proved suitable for the separatlon of alkall-metal cations and ammonium. Detectlon llmits were In the range 0.3-6.7 ppb for conductlvlty detection and 0.2-21.0 ppb for UV absorptlon detection. Alkaline-earth-metal catlons could be separated by using hlgher concentrations of the same eluent specles, glvlng detectlon limits of 9-917 and 1.3-1370 ppb for conductivity and UV absorption detection, respectlvely. Aromatlc base eluents were applied to the separatlon of calcium and magneslum In seawater and are potentlally sultable for the determlnatlon of aluminum.

Isotopic separation of lithium ions by capillary zone electrophoresis

“…Effective mobility of the probe ion might than be controllably decreased by BGE pH adjustment to match the mobility of lithium ions of 4.1 × 10 −4 cm 2 V −1 s −1 [15]. We used 4-aminopyridine with ionic mobility of about 4.9 × 10 −4 cm 2 V −1 s −1 [16]. 4-Aminopyridine was chosen for our experiments as it usually gives some increase in sensitivity compared to other fast migrating probe ions, such as creatinine or imidazole, due to higher absorption in UV region (ε = 18 500 at 261 nm) [17][18][19][20].…”

Peer Reviewed: Ion Chromatography Retrospective

“…Typical eluents used for the nonsuppressed IC of anions with conductivity detection were aromatic carboxylates, such as benzoate and phthalate, whereas aromatic bases could be used for cation separations (9). All of these species were bulky ions with low limiting ionic conductances (< A UV-absorbance detector (that was often borrowed from the lab's HPLC setup) was frequently used instead of a conductivity detector.…”

Application of pure silica gel as cation-exchange stationary phase in lon chromatography with indirect photometric detection for common mono-and divalent cations using aromatic monoamines as eluents

“…One of the best ways for the elimination of these drawbacks is to utilize protonated aromatic monoamines with high UV-absorbance as the eluent ions. Haddad and Foley have demonstrated the effectiveness of protonated aromatic monoamines as the eluent ions in IC-IPD using lightly sulfonated PS-DVB resin as the cation exchange stationary phase for various cations [9].…”