Improved chemical stabilities for end-capped high performance liquid chromatography stationary phases based on poly(methyloctadecylsiloxane) thermally immobilized onto metalized silicas.

Improved chemical stabilities for end-capped high performance liquid chromatography stationary phases based on poly(methyloctadecylsiloxane) thermally immobilized onto metalized silicas.

Journal of chromatography. A (2012-09-12)

Carla G A da Silva, Carol H Collins

ABSTRACT

Endcapped stationary phases were prepared after thermal immobilization of poly(methyloctadecylsiloxane) (PMODS) onto zirconized and titanized silica supports. These new stationary phases have lower densities of residual hydroxyl groups, according to infrared spectroscopy and 29Si CP-MAS NMR and as shown by the symmetrical peaks of basic compounds from the Tanaka, Engelhardt and SRM 870 test mixtures. Stability tests for the endcapped stationary phases, measured using severe alkaline conditions (70:30 (v/v) methanol:0.05 mol/L K2CO3/KHCO3, pH 10, 50 °C), revealed that the stabilities of these phases are greater than the stabilities of similar nonendcapped phases. The stationary phases showed good performance for the separation of basic pharmaceuticals.

MATERIALS

Product Number

Brand

Product Description

736198

Supelco

Ethylbenzene solution, NMR reference standard, 10% in chloroform-d (99.8 atom % D), NMR tube size 5 mm × 8 in. , ultra-thin wall

708046

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 10% in chloroform-d (99.8 atom % D)

612065

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 10 mm × 8 in.

612480

Supelco

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), chromium(III) acetylacetonate 0.1 mg/mL, TMS 0.01 %, NMR tube size 5 mm × 8 in.

487104

Supelco

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 5 mm × 8 in.

487120

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 8 mm × 8 in.

551341

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 5% in chloroform-d (99.8 atom % D), TMS 2 %, NMR tube size 5 mm × 8 in.

714917

Sigma-Aldrich

Ethylbenzene solution, NMR reference standard, 0.1% in chloroform-d (99.8 atom % D), TMS 0.01 %, NMR tube size 5 mm × 8 in. , ultra-thin wall

296848

Sigma-Aldrich

Ethylbenzene, anhydrous, 99.8%

03079

Supelco

Ethylbenzene, analytical standard

E12508

Sigma-Aldrich

Ethylbenzene, ReagentPlus^®, 99%