In a recent survey*, almost three-quarters of lab managers cited instrument maintenance/downtime as their biggest laboratory challenge. With the latest inductively coupled plasma-optical emission spectroscopy (ICP-OES) instruments, this challenge remains. The intricate sample introduction hardware – nebulizer, spray chamber, torch, sampler, and skimmer cones – can be tricky to keep in good condition. There are three critical areas for concern to consider when maintaining these instruments:
- Understanding sources of experimental error
- Minimizing variation during sample introduction
- Ensuring optimized instrument performance
Here, we look specifically at the nebulizer and how to prevent it causing bottlenecks in the workflow. These recommendations will help to ensure robust, stable analysis, and achieve your laboratory goals.
Let’s first look at nebulizer choice and how to make sure you are picking the best tool for your application. Each nebulizer has different performance characteristics. The inert Agilent OneNeb Series 2 nebulizer is suitable for most samples and provides excellent efficiency and precision, together with tolerance to dissolved solids and hydrofluoric acid resistance. Glass-concentric nebulizers are suitable for most aqueous samples and K-style nebulizers provide best performance with organic solvents. The performance characteristics of common nebulizers are summarized in the Agilent Nebulizer Selection Guide.
Prevention and cure
Blocked nebulizers cause trouble: they can restrict aerosol formation, decrease sensitivity, and degrade accuracy and precision. The first thing to keep in mind when nebulizing samples is that the flow is low. This means that the capillary carrying the sample or solution into the spray chamber has little tolerance to undissolved solids and large particulates. Therefore, with challenging samples, there is a high risk you may block the annulus or the capillary.
There are a range of sample preparation procedures that can be completed to prevent blockages. First, filter your samples. Using Agilent sample filters, you can remove the particulates that cause blockages in one step. Filtering solvents and other solutions used in sample preparation or introduction will pay dividends and prevent any blockages in the system.
Second, using autosampler enclosures will prevent any dust going into your samples. Adjusting probe height on the autosampler so that you are sampling above any dissolved solids in the solution can also help.
In your day-to-day routine, you can minimize blockages and achieve the longest operational use by following these five simple recommendations:
- Always cover the sample container.
- Flush with clean rinse solution between samples and at the end of a run to help prevent deposits forming in the nebulizer.
- Nebulizers with broken or chipped tips should be discarded.
- Mist formation in the glass cyclonic spray chamber is a good indicator that a nebulizer is performing satisfactorily.
- Blockages may be cleared by pumping rinse solution through the nebulizer. Backflush if this doesn’t clear the blockage.
To find out more, download our free technical instructional guide: ‘Simple Steps for Clearing a Blocked ICP-OES Nebulizer’, available here.
Supporting your streamlined workflow
Take advantage of one of our experts: Eric Vanclay, Spectroscopy Supplies Product Marketing Manager, Agilent Technologies, Australia, in the on-demand webinar: ‘Trusted advice to help you maximize your ICP-OES instrument performance and uptime’. Eric covers his top recommendations to take the pain out of everyday ICP-OES operation. He also discusses new workflows for routine analysis that reduce downtime, increase throughput, and improve data quality, and presents tools that are easy to implement in every lab. View the on-demand webinar here.
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*2017 Agilent Independent Survey of 700 Lab Managers: data available here.