tailieunhanh - Introduction to Modern Liquid Chromatography, Third Edition part 18

Introduction to Modern Liquid Chromatography, Third Edition part 18. High-performance liquid chromatography (HPLC) is today the leading technique for chemical analysis and related applications, with an ability to separate, analyze, and/or purify virtually any sample. Snyder and Kirkland's Introduction to Modern Liquid Chromatography has long represented the premier reference to HPLC. This Third Edition, with John Dolan as added coauthor, addresses important improvements in columns and equipment, as well as major advances in our understanding of HPLC separation, our ability to solve problems that were troublesome in the past, and the application of HPLC for new kinds of samples. . | 126 EQUIPMENT The influence of temperature on chromatographic separation suggests that in most cases some means of column temperature control is necessary. Even though the laboratory as a whole may have adequate climate control an individual location in the laboratory may experience temperature fluctuations of several degrees as the heating ventilating and air-conditioning HVAC system cycles. The use of a column oven oneveryHPTC system isstrongly recommendto maintainconstant temperature. Of the colemnovrn doec nel preheatdie mobile phrte gtnerdly required only formethodtoperoling rt Od0Ci ostmplepreheatcrpanbtfaOricated from m . shsuld bcconnatted to the column reiist andmountedinside thecolrmnooan preferab e ioeovtvctwitO a heated sintnec. Oi n rn ne Three colsme-oven .edgnsare poprlar blnckdeater air bath Pehmhe ater Water-batnheoteetareaoimpte are inconvenient and seldom used today. If for rome eepsvn a column oven is not used temperature fluctuations should be minimmed by wrapping the column in an insulating material . foam pipe-wrap . BlonOneaiee . .s. . --s. t . ede. ie t . dsd. . . the heat is transferred from a grooved aluminum block into which the column is clamped withtant provided by a cartridge-type heater. The column and heating block are contained in an insulated compartment. In another format a flexible blanket of beating tape iswrapped around the column. The direct contact of the colunrnoatn die neatae orovides eSficirnt hcdpoig 1tn .IeaOditevna solvenr preheatinger neceserry draherterccn ba nnedrs dnscritee abnve. Ait Beth T ait-bash tey . r eonsmeoaddia vac fi. e par nh1ilmaipgnaphy . tta tagniyrftocmp at ev tt ps lnvni trmnerr urr. Aar .or 11 rtam i than with a block heater PfliierHapSor Peltier heatersaraprpuloe for HP. .work. Io edde iontonnosinp tner can control thecolnmn oven to anioirnlien or befotv wisltout