Improvements in HPLC instrumentation, suppressor technology and ion-ex
change columns have occurred over the past several years to the point
where an ion chromatograph can now be configured for anion analysis us
ing a considerable variety of hardware, suppressor and column combinat
ions. A number of parameters, including hardware configuration, effect
of temperature, column type and suppressor device, were studied with
a view toward optimizing the performance of an ion chromatographic (IC
) system. It was found that dual-piston, reciprocating pumps used with
few-pressure pulse dampeners significantly reduced baseline noise for
both suppressed and non-suppressed conductivity detector combinations
, while column temperature control proved essential in order to achiev
e routine sub-ppb detectability in non-suppressed IC. In general, the
use of suppressed IC resulted in lower detection limits than non-suppr
essed IC when using the same columns and hardware. Of the columns stud
ied, the methacrylate-based HR column was found to give the best overa
ll separation selectivity when using a carbonate-bicarbonate eluent an
d suppressed conductivity detection. The majority of column and suppre
ssor combinations evaluated gave acceptable performance, although some
gave less than satisfactory results. Also, some combinations resulted
in lower than expected analytical results, particularly for chloride,
when quantitated using single-point calibration. In addition to the u
se of commercially available suppressor devices, there is also a large
number of high-capacity cation exchangers which can be used as suppre
ssors and these columns, in some instances, may offer equivalent (or s
uperior) performance compared to the commercial devices.