IMPORTANT NEWS FOR GAS AND LIQUID CHROMATOGRAPHERS: A permanent, chemically-bonded liquid phase Announcing DURAPAK,™ Waters' new breakthrough in GC and LC packing materials Here at Waters, the manufacturer of PORAPAK®, we've found a way to chem ically attach a liquid coating permanently to a column-support material. It's the same material described by Professor Halasz as "Brushes" at the Las Vegas Chromatography Symposium*. We call it DURAPAK. Consider the following advantages of the Durapak materials: For the Gas Chromatographer: • Speed of analysis (up to 50 plates/sec) comparable to that of capillary columns but without capillary-column disadvantages. • High-efficiency separations (over 1,000 plates/foot). • Permanently bonded liquid phase with no vapor pressure, consequently no bleed ing. Baseline therefore remains stable throughout temperature programming, eliminating the need for dual columns and dual detectors. • Unique permanent liquid coatings result
ing in higher reproducibility. • Columns quickly equilibrated because the • Greater loadability with no loss of effi liquid phase is permanent. ciency over a wide range of sample sizes. • No need for a presaturator column. • Symmetrical peaks with non-polar and • Fast equilibration of column permits quick even with highly polar compounds. mobile-phase changeover. • High relative retentions for isomeric com Durapak Availability pounds. The types of Durapak now available are • Separation efficiencies independent of OPN/Porasil, a permanent bond of oxyprotemperature, retention time, sample func pionitrile and Porasil® porous silica beads; tionality, and sample size. Carbowax 400/Porasil; and a straight-chain For the Liquid Chromatographer: hydrocarbon on Porasil. These will be avail • Permanently bonded liquid phases which able in two size ranges for gas chromatog won't dissolve in the mobile phase; there raphy and two size ranges for liquid chromatography. We are now developing fore, no bleeding. • Separation efficiency comparable to gas additional Durapak materials having a wide polarity range. chromatography (one plate/sec). • High partition ratios (k') with high rela Durapak is big news to every gas and tive retentions. liquid chromatographer. For more informa • Reproducible symmetrical peaks for sam tion, write or call Waters Associates Inc., 61 ples with partition ratios up to 100. Fountain Street, Framingham, Mass. 01701. • Unique capability to resolve difficult sep Phone (617) 879-2000. arations. 4339
*Durapak is based on the development described at the Fifth International Symposium on Advances in Chromatography, Las Vegas, January 1969, by Pro fessor I. Halasz, University of Frankfurt, in a talk en titled " 'Brushes' as a Stationary Phase in Chroma tography." To be published.
DURAPAK FOR LIQUID CHROMATOGRAPHY
DURAPAK FOR GAS CHROMATOGRAPHY ANAL /OPER. CONDITIONS ANAL./OPER. CONDITIONS COLUMN 100cm, DURAPAK OPN/PORASIL, I 5 0 / Z E 5 MESH TEMP; 150° C LINEAR VELOCITY; 7.4 cm/sec. t. tiC| 2-nC 5 3. nC6 4 CHLOROFORM 5. BENZENE 6. hCg 7. TOLUENE 8.DIETHYL ETHER 9. nCg IO.ETHYL BEN2ENE ll.p-XYLENE 12 o-XYLENE l3.nC| 0 14 MESITYLFNE !5.nCji
COLUMN" l'x.093" I. D., DURAPAK OPM/P0RASIL, 36-75μ SOLVENT ISO-OCTANE FLOW I 95 ml/min SAMPLE SIZE: 6JI\
i O, 0-DIMETHYL CHLQROTHlO PHOSPHATE 25m9/ml 2 CARBOPHENOLTHION 25mq/ml
WATERS ASSOCIATES See us at the ACS Chemical Exposition, Booth Nos. 38 and 55 Circle No. 67 on Readers' Service Card
