Columns cation chromatographic

The first enhancement column was constructed of plastic (4.6x50mm) and packed with a cation exchange resin in the K+ form (TSK SCX Tpm TSK IC-Cation for cation chromatographic use, 10pm silicon based material with low cation exchange capacity). 

Fig. 9. Norepinephrine and dopamine release from brain slices (slices of rat nucleus accumbens). (A) Dopamine standard (10 pmol injected onto column—volume 100 pi) (B) norepinephrine standard (10 pmol injected onto column—volume 100 pi) (C) supernatant obtained after incubation of one sliced nucleus accumbens in Krebs buffer containing pargyline (10 M) at 37°C for 10 min, followed by centrifugation (Bennett et ai, 1981fl). The supernatant is deproteinized by addition of 20 pi 0.1 M perchloric acid per 2 ml supernatant and then centrifuged, and 100 pi is injected onto the column. Note the small norepinephrine and large dopamine peaks (D) same as C, except the nucleus accumbens (the other accumbens from the same animal as in G) was incubated in the presence of d-amphetamine (10 M). Note the increased norepinephrine and dopamine peaks. Chromatographic conditions column, cation-exchange Nucleosil (10 p) 30 cm X 2.1 mm mobile phase, 0.05 M acetate/citrate, pH 4.8 flow rate, 1.2 ml/min electrode potential, +0.65 V sensitivity, 2 nA/V full scale deflection volume injected, 100 pi.

Fig. 11. 5-HT spinal cord assay. Sample recordings of (A) 5-HT standards (10 pmol injected onto the column) (B) rat lumbar spinal cord saline injected tissue weights 61.0 and 61.3 mg (C) rat lumbar spinal cord tetrabenazine (75 mg/kg) administered 6 hr before sacrifice tissue weights 60.0 and 56.4 mg (D) rat lumbar spinal cord tetrabenazine (75 mg/kg) administered 24 hr before sacrifice tissue weights 70.0 and 68.3 mg. Chromatographic conditions column, cation exchange (Vydac 40 x), 50 cm x 2.1 mm mobile phase, acetate/ citrate, 0.2 M, pH 4.8 flow rate, 0.9 ml/min electrode potential, +0.60 V sensitivity, 2 nA/ V full scale deflection volume injected onto the column, 20 xl tissue extraction, acidified butanol (Ponzio and Jonsson, 1979). Note the rapid depletion of cord 5-HT caused by tetrabenazine followed by partial recovery within 24 hr. Full recovery is seen after 48 hr (Marsden, Bennett, Emson, and Gilbert, in preparation).

An ion chromatographic system that included column switching and gradient analysis was used for the deterrnination of cations such as Na", Ca ", Mg ", K", and NH" 4 and anions such as Cf, NO, NO , and in fog water samples (72). Ion-exchange chromatography compares very well with... 

Feibush, B. and Santasania, C. T., Hydrophilic shielding of hydrophobic, cation- and anion-exchange phases for separation of small analytes direct injection of biological fluids onto high performance chromatographic columns, /. Chromatogr., 544, 41, 1991. 

Ionic or partially ionic compounds can be chromatographed on reversed-phase columns through the use of ion-pairing reagents. These reagents are typically long-chain alkyl anions or cations that, in dilute concentrations, can increase the retention of analyte ions. For cationic compounds, C5 to CIO alkyl sulfonates are commonly used combinations may also be used... 

The influence of various structural and physicochemical parameters of the stationary and mobile phases on the tailing of a cationic dye in reversed-phase chromatography has been studied in detail. Measurements were performed in a C8 reversed-phase column (80 X 4.6 mm). The isocratic mobile phase was ACN-0.01 M aqueous HC1 (90 10, v/v). Analyses were carried out at 20°C and the flow rate was 1-5 ml/min. The concentration of the cationic dye, l,l -didodecyl-3,3,3, 3 -tetramethylindocarbocyanine perchlorate (Dil) in the model solutions varied between 0.9-309 pM. The dependence of the chromatographic profile of the dye on the injected concentration is illustrated in Fig. 3.112. Calculations and mathematical modelling indicated that the peak tailing of the dye can be... 

A high-throughput approach to HPLC-MS/MS for metabolite identify-cation was also described by Dear and co-workers [29], where up to six hydroxylated isomers were chromatographically resolved in 1 min with the overall cycle time reduced to 5 min on a monolithic column (4 mL/min). 

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