Margandan Bhagiyalakshmi

Utilization of rice husk ash as silica source for the synthesis of mesoporous silicas and their application to CO2 adsorption through TREN/TEPA grafting

Mesoporous MCM-41, MCM-48 and SBA-15 were synthesized using Rice husk ash (RHA) as the silica source and their defective Si-OH sites were functionalized by 3-chloropropyltrimethoxysilane (CPTMS) which was subsequently grafted with amine compounds, Tris(2-aminoethyl)amine (TREN) and Tetraethylenepentamine (TEPA). X-ray powder diffraction (XRD) and BET results of the parent mesoporous silica suggested their closeness of structural properties to those obtained from conventional silica sources. CO(2) adsorption of branched amine TREN and straight chain amine TEPA at 25, 50 and 75 degrees C was obtained by Thermogravimetric Analyser (TGA) at atmospheric pressure. TREN grafted mesoporous silica showed 7% of CO(2) adsorption while TEPA grafted mesoporous silicas showed less CO(2) adsorption, which is due to the presence of isolated amine groups in TREN. TREN grafted mesoporous silicas were also observed to be selective towards CO(2), thermally stable and recyclable. The order of CO(2) adsorption with respect to amount of amine grafting was observed to be MCM-48/TREN>MCM-41/TREN>SBA-15/TREN.

LIQUID CHROMATOGRAPHY-ELECTROSPRAY TANDEM MASS SPECTROMETRY (LC-MS/MS) DETERMINATION OF LANSOPRAZOLE IN HUMAN PLASMA

A rapid, selective, and sensitive LC-MS/MS method has been developed and validated for quantification of lansoprazole (LZ) in human plasma using esomeprazole as an internal standard (IS). The analyte and IS were extracted by single solvent liquid-liquid extraction using tert-Butyl methyl ether and separated by isocratic elution on C18 analytical column with 90:10 v/v acetonitrile, and 20 mM ammonium acetate (flow rate of 1 mL/min) as the mobile phase in the positive ion mode. Selected Reaction Monitoring transitions for LZ, internal standard and their daughter ion were observed at 369, 346, 252, and 198 m/z, respectively. The lower limit of quantification was 3.997 ng/mL and total run time for the analysis was 1.2 minutes. Linear calibration was observed in the range of 3.997 ng/mL to 2002.5 ng/mL. The method was validated for its selectivity, stability, accuracy, precision, and recovery.