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Electrolytic suppressors are the easiest to use. They generate their own regenerant inside the suppressor with water, either in recycled eluent mode or external water mode. In recycled eluent mode, the water used for regeneration comes from recycled suppressed eluent, making this mode of operation the easiest to use. In external water mode, the water is delivered from an external source, either pneumatically using pressurized gas, with a second pump, or directly from a deionized water system (with a flow-rate regulator). However you choose to set it up, you do not have to prepare any regenerants using chemical reagents.
Chemical suppressors sacrifice some ease of use compared with electrolytic suppressors because they require manually prepared chemical regenerant. However, the regenerant is passed through a parallel channel, allowing for continuous regeneration. Preparing regenerant solutions, such as sulfuric acid, is time-consuming and increases occupational health and safety risks.
Packed bed suppressors are based on decades-old technology first developed in the 1970s. This type of suppressor has a finite capacity and must be taken offline for regeneration. One workaround is the rotating packed bed suppressor, which is three suppressors in one that rotate between analyses. While one suppressor channel is used in the analysis, the second one is regenerated and the third is rinsed. This poses several problems for method validation, due to the channel-to-channel baseline fluctuations and the possibility that the in-use suppressor cartridge will exhaust before the analysis is complete, particularly for analyses with long run times or strong gradients. The primary concern is related to method validation.
Assembling a complete electrolytic suppressor unit is a highly complex, delicate process. Since the ion-exchange resin and ion-exchange membranes are an integral part of the suppressor unit, we cannot offer a replaceable ion-exchange option.
In contrast, for a packed bed suppressor, the exchange of a cheap cartridge rotor is simple and easy to cover under warranty. In general, the 10-year warranty applies only to the suppressor rotor, not to the stator, the actuator (stepper motor that drives the suppressor switching), or to the regenerant delivery systems like a peristaltic pump or syringe pump.
Competitor warranties have several stipulations that don’t make sense for most labs—they require that the suppressors not be used continuously, a rigorous verification process be followed, all system maintenance be performed by the system manufacturer (at the owner’s expense after the first year, including field service engineer travel), and that the suppressor be sent back to the manufacturer at the customer’s expense. This makes the warranty extremely costly for the customer and requires lengthy system downtime that is unacceptable for most of our customers.
We strive to limit the number of chemicals in your lab to help reduce disposal costs and for the health and safety of our customers. Packed bed cation suppressors require a mobile phase spiked with an uncommon alkaline or alkaline earth metal such as rubidium to promote the suppressor reactions. Rubidium is classified as hazardous waste, which makes it very expensive to dispose of. For a packed bed anion suppressor, a potentially harmful strong acid regenerant, such as sulfuric or phosphoric acid, is required.
No. In addition to eliminating the need to dispose of hazardous waste, newer suppressor technology offers several other maintenance savings.
We offer high-efficiency suppressors with high-capacity and high-efficiency columns—this gives you the best detection limits and the ability to handle complex samples.
No. The biggest concern with validated methods is multiple suppressor cartridges because they must all be validated separately, and the operator must keep track of which suppressor cartridge was used for each analysis. In strictly validated environments, only one suppressor cartridge can be validated, which can greatly reduce throughput in systems with multiple suppressor cartridges—the second and third cartridges cannot be used for analysis and the entire system is idle during regeneration and rinsing of the operational suppressor.
All Thermo Scientific Dionex suppressors use a single suppressor that requires one-off validation, with only one system-level calibration and blank per analytical sequence.
We understand that you want to get your analysis done as quickly as possible. Luckily, once properly hydrated, our suppressors can run continuously without any interruptions. Older suppressor technology requires more steps—regenerant preparation, preparation of a flush solution and pump maintenance—which can lead to long start-up times and down-times.