Intercomparison of High Performance Liquid Chromatography Columns
for the chromatography of Anions. Final Report
Report No DWI0670
Of the columns evaluated the best in terms of overall general performance were the Dionex AS4A (with guard column), and the Waters Anion column. Good results were obtained with the Vydac 302 IC, the Spherisorb 5u ODS-1, and the Polymer labs PLRP-S but using the TBA/phthalate mobile phase and detection at 267nm by indirect UV .
The Chrompack Ionosphere gave very high back pressures very quickly which the other columns did not.
The Hamilton PRP-X100 shows poor efficiency and relatively poor capacity and selectivity but offered some interesting separations (Fig 1).
The PLRP-S column with the "Wheals" eluant was unsuccessful for us.
The Waters anion column showed great versatility because of the range of mobile phases that could be used (Fig 2).
Our Dionex AS4A (a new column) lost all retention capacity upon storage in the recommended storage solvent for 2 weeks.
Considering detection principles we found that the use of Refractive Index either directly or indirectly gives poor stability and sensitivity.
Indirect W detection is very satisfactory when the mobile phase, and the samples to be analysed are suited to this particular technique. It is recommended as a low cost option for low concentrations in aqueous samples e.g. natural waters - NO3 , S04 , Cl etc. The presence of a system peak extends the unit analysis time.
Suppressed conductivity detection worked well with the AS4A whereas unsuppressed conductivity was perfectly satisfactory where the mobile phase was suitable for this mode of detection.
The Waters conductivity detection utilising electronic suppression gave the best results of all in terms of stability and sensitivity.
Cross ion interference.
The results are shown in the Table below.
|Vydac 302 IC||/||X|
Copies of this report may be available as an Acrobat pdf download under the 'Pre 2000 Reports' heading on the DWI website.