The Column - June 2009 - 9

Tips & Tricks: GPC/SEC How Does the Flow-rate Influence GPC/SEC Results? Thorsten Hofe and Daniela Held, PSS Polymer Standards Service GmbH, Mainz, Germany. Molar mass determination in GPC/SEC using a calibration routine with reference materials is based on the precise measurement of the elution volume of the sample. Neither the peak height, nor the peak area itself are evaluated, but the absolute peak position and the peak shape. This is one of the major differences between HPLC and GPC/SEC. GPC/SEC experiments are run under isocratic conditions. Solvent composition and flow-rate are kept constant for the whole experiment. Method development for GPC/SEC requires the selection of the proper column and solvent,1 as well as the optimum flow-rate. The flow-rate influences the diffusion behaviour and, therefore, the column performance, resolution and accuracy. One of the aims in GPC/SEC is to minimize the peak spreading described by the Tung axial dispersion equation.2 If a GPC/SEC experiment is performed with the wrong flow-rate, additional peak broadening and sample shearing may take place. Three terms (A, B, C) contribute to the van Deemter equation: the eddy diffusion (or eddy dispersion), the longitudinal diffusion of the solute while passing through the column and the (interphase) mass transfer. While, eddy diffusion does not depend on , longitudinal diffusion decreases with increasing and mass transfer increases linearly with (compare Figure 1). As a result of all three terms, Figure 1 also shows the overall dependency of the plate height as a function of the flow. However, the flow-rate set at the pump itself, is not universal enough for a general description. To compare different column dimensions, the flow-rate has to be normalized by the cross sectional area of the column. Then the linear flow can be discussed. Figure 2 shows van Deemter curves for columns with three different dimensions. It clearly shows that the minimum for the plate How Do I Find the Optimum Flow-rate? It is a well-known fact that there is an optimum flow-rate for the mobile phase, at which the best resolution is achieved. The well-known van Deemter equation helps to select the proper flow-rate in GPC/SEC.3 It is used to explain band broadening and relates the height of a theoretical plate (which can also be seen as 1/plate number, N) to the flow. At the lowest point of the van Deemter curve (lowest plate height, H), the diffusion behaviour of the sample through the column is at its optimum and the band broadening of the peak is minimized. The height H of the theoretical plate is given by H A B C [1] where is the velocity. 9 1 9 Contents Tips & Tricks 2 13 Vosloo Rainville and Mather 6 17 News Meeting Review 8 20 Market Trends & Analysis Events & Contacts Ilovephoto Design/Getty Images

The Column - June 2009

Table of Contents for the Digital Edition of The Column - June 2009

The Column - June 2009
Laboratory Equipment Qualification: Back to Basics
News
Market Trends and Analysis
Tips & Tricks: GPC/SEC
Confirming Peak Identification in Bioanalytical Studies Using Dual-Scanning MS Technology to Achieve ProductIon Confirmation
Meeting Review
Events
The Column - June 2009 - The Column - June 2009
The Column - June 2009 - Laboratory Equipment Qualification: Back to Basics
The Column - June 2009 - 3
The Column - June 2009 - 4
The Column - June 2009 - 5
The Column - June 2009 - News
The Column - June 2009 - 7
The Column - June 2009 - Market Trends and Analysis
The Column - June 2009 - Tips & Tricks: GPC/SEC
The Column - June 2009 - 10
The Column - June 2009 - 11
The Column - June 2009 - 12
The Column - June 2009 - Confirming Peak Identification in Bioanalytical Studies Using Dual-Scanning MS Technology to Achieve ProductIon Confirmation
The Column - June 2009 - 14
The Column - June 2009 - 15
The Column - June 2009 - 16
The Column - June 2009 - Meeting Review
The Column - June 2009 - 18
The Column - June 2009 - 19
The Column - June 2009 - Events
The Column - June 2009 - 21
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn030713_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn030713
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn030713_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn021813_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn021813
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn021813_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020413_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020413_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020413
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn011513_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn011513_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn011513
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120312_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120312_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120312
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn112112_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn112112
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn112112_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110712_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110712
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110712_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn102412_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn102412_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn102412
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100412_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100412_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100412
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092012_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092012_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092012
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090612_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090612_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090612
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082212_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082212_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082212
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn080212_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn080212_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn080212
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn071812_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn071812_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn071812
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn070412_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn070412_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn070412
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn062212
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn062212_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn062212_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn060812_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn060812_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn060812
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn051712_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn051712
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn051712_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn050212_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn050212_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn050212
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn041912_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn041912_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn041912
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn040212mkt
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn040212_v3
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn040212_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn040212
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn032112
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn032112_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn030712_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn030712
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn022212_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn022212
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020112_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020112
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn011612
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn011612_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120611
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120611_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn111611
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn111611_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110711_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110711
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn101711
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn101711_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100711
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100711_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092111_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092111
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090611_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090611
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082211_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082211
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn080511_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn080511
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn071511_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn071511
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn070111_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn070111
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn061711_hplc
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn061711_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn061711
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn060611_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn060611
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn051811
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn051811_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn050911_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn050911
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn041811_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn041811
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn040111_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn040111
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn031811_v2_test
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn031811_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn031811
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn03042011_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn03042011
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn022111_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn022111
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020411
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020411_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn012411_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn012411
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn012711_pittcon
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120710_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120710
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn111910
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn111910_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110510_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110510
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn102210_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn102210
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100810_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100810
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092410_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092410
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090710
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090710_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082010v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082010
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn080610_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn080610
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn072310
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn072310_v2
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn070210
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn062110
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn060710
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn052410
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn051010
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn042310
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn040610
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn031910
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn030510
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn022210
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn020510
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn012210
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn121709
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn120709
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn111909
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn110509
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn102209
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn100809
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn092409
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn090409
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn082009
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn0809
http://digital.findanalytichem.com/nxtbooks/advanstaruk/thecolumn0709_v2
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0709
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0609
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0509
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0409
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0309
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0209
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0109
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1208
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1108
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1008
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0908
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0808
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0708
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0608
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0508
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0408
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0308
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0208
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0108
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1107f8
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1207
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1107
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1007
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0907
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0807
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0707
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0607
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0507v2
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0507
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0407-insert
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn-shimadzu0407
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0407
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0307
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0207
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0107
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1206
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1106
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1006
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0906
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0806
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0706
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0606
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0506
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0306
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0206
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn0106
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1105s
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1205
http://www.nxtbook.com/nxtbooks/advanstaruk/thecolumn1105
http://www.nxtbookMEDIA.com