tailieunhanh - HPLC A Praactical User'S Guide Part 12

Tham khảo tài liệu 'hplc a praactical user's guide part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 218 GLOSSARY OF HPLC TERMS Retention Time The time or mobile phase volume need to elute and detect a component of the mixture in a detector. Reverse-Phase Chromatography Separation mode on bonded phase columns in which the solvent column polarities are the opposite of normalphase separations. Polar compounds elute before nonpolar compounds Nonpolar columns require polar solvents. RP18 Reverse phase bonded packing with 18-carbon side chain. See C18 ODS. Rotor Seal TeflonR surface that seals the injector and separates the flowing mobile phase from the sample loop until an injection is completed. Sample Clarification Removal of particulates from the injection sample by either filtration or centrifugation. Saturation Column Sacrificial column placed before the injector to protect the main column from pH degradation. Seal Wear surface that both lubricates and separates moving parts in the HPLC. See Plunger Seal Rotor Seal and Needle Port Seal. SEC Size Exclusion Chromatography A separation mode employing control pore size packing to achieve resolution of molecules based on size and shape. See GPC. Separation Factor a A measure of peak separation between peaks. Product of dividing one peak k by the other. Also called the chemistry factor because it is controlled by changes in the chemistry of the column mobile phase and the sample. SFE Separation and filtration cartridge column. Also referred to as a SPE solid phase extraction column . See windowing in Chapter 12. Silica Particles or spheres of crystalline silicic acid used in chromatography. Its surface is polar acidic and tends to attract water of hydration and polar compounds. Silylation The first step in forming bonded-phase packings from dried silica and chlorodialkylchlorosilanes. Stationary Phase A term used to describe the column packing indicating that it is part of a two-phase equilibrium with the mobile phase or column solvent. Syringe Pump A pulseless pump made up of a motor-driven piston or plunger in a .