I need to develop a method using a conductivity detector. We have the old Waters model 430 one is sitting in the lab for many ears. Is anybody had an experience with this particular model? Is it good, bad, should be avoided? How much newer detectors (from Alltech, Dionex, Waters, Metrohm) advanced since model 430?

The waters 430 is a good detector. If it works ok (after sitting long time in the lab), you may run most of the application on that detector. If you need to go to the limits of IC, newer models may have advantages. For more details I would need more information about the application.

As mentioned above, the Waters 430 is a good detector (it's actually an OEM from Tosoh) but it does have a couple of significant limitations compared to newer detector designs. For one thing, there is no independent control of signal filtering. It's hidden in one of the sensitivity control functions (either the gain or the range, I've forgotten which). Certain combinations of gain and range will result in very significant degradation in chromatographic performance caused by excessive filtering of the detector signal. Of course, it can sometimes be useful to employ such filtering but it's better to have this as a discrete independent variable than one that's connected to another function such as range or gain. Secondly, there isn't the possibility of independently varying column temperature and cell temperature. You are stuck with the default as far as temperature control is concerned. Since it's preferable to operate with your column temperature set below your cell temperature, this limits your options in terms of column temperature. Both of these variables (cell temperature and filtering) are available as independent control parameters in most modern conductivity detectors, so this is one reason you might want to consider one of the newer detectors from one of the vendors mentioned above.

Also, I found that zeroing this detector can be somewhat frustrating when working under conditions where high levels of filtering are being employed and high sensitivity ranges are being used. Often, because of the lag between rotating the fine control knob and the observed changes in the baseline, one repeatedly sends the signal off-scale, first to one extreme and then the other extreme. Usually, I found it took quite a number of tries to zero the baseline under these conditions. Newer detectors have electronic auto zero, and as such avoid this problem.

But, having said that, I'm sure this detector can provide good data assuming it's still in good working order.