Set up an ICP-OES Worksheet with Internal Standard while Bypassing the AVS

Created by Whitney Blackmon 3 months ago | Last modified by Carlos Vargas 22 days ago

This Information Applies To: 5000 series ICP-OES (5100,5110,5800,5900), AVS 4/6/7, ICP Expert version 7.X

Issue

The AVS can contribute to instrument performance issues such as sensitivity and precision. During troubleshooting, bypassing (or skipping) the AVS and running a worksheet during can identify if the AVS is the root cause of the issue. Other root causes could be the method application, or an instrument fault.

Items Required

If an internal standard line is required, install the internal standard tubing on the peristaltic pump and locate a Y-piece connector (p/n 1610132400).

Resolution / Steps to Follow

To bypass the AVS, see Bypassing the AVS for the 5000 Series ICP-OES .
Connect the Y-piece connector to the internal standard tubing, sample tubing, and add a short length of tubing from the Y splitter fitting to the nebulizer (Figure 1):

Figure 1. Connection of Y-piece for Internal Standard
1. Y Splitter, 2. Internal standard tubing, 3. Sample tubing, 4. Mixed solution to nebulize
Place the internal standard line in the internal standard solution and the sample line in DI water. Close and adjust the peristaltic pump roller arms.
Turn on the peristaltic pump at normal pump speed (via the Instrument Page in ICP Expert). Confirm the solution in the sample and internal standard lines are being delivered to the nebulizer at a smooth steady rate. Adjust the peristaltic pump roller arm tension if needed.
Check that the spray chamber is draining into the rinse vessel, then turn off the peristaltic pump (via the Instrument Page in ICP Expert).
Create a worksheet from the template used to run the analysis with the AVS. Select ICP Expert > File > New From > select your template > Open (Figure 2):

Figure 2. ICP Expert home page
Select the Configuration tab > deselect the AVS 6/7 check box (Figure 3):

Figure 3. Deselect the AVS 6/7
Select the Conditions tab, edit the parameters (Figure 4):
1. Common Conditions > Uptake delay (s). The uptake delay will depend on the length of the autosampler tubing and the nebulizer capillary. It is recommended to use a stopwatch to time how long it takes for the sample to reach the nebulizer with the peri-pump speed set to ‘Fast pump’.
2. Common Conditions > Rinse time (s). The rinse time will depend on the length of the autosampler tubing, length of the nebulizer capillary and the identity of present elements and concentrations. If you suspect carry-over, increase the rinse time.
3. Measurements Conditions > Stabilization time (s). The stabilization time will need to be greater than it was when using the AVS. Set the stabilization time to a minimum of 15 sec.
  
  Tip: The recommended stabilization time must be long enough for the solution to reach the plasma. When in doubt, increase the time settings on the Conditions page
  
  Figure 4. Conditions tab
Select the Sequence tab and confirm the standard and/or sample locations (Figure 5):

Figure 5. Sequence tab. Verify that rack tube matches sample/standard tube placement on the autosampler
Save the worksheet and click Run to start the analysis (Figure 6):

Caution: Save changes made to the worksheet as a new file name to avoid changes to the worksheet set up for AVS use

Figure 6. Save changes and run the worksheet
If this worksheet completes with acceptable results, an AVS component is the most likely root cause of the poor instrument performance. See the AVS part replacement topics in the ICP Expert Help, How To Section for instructions on replacement (Figure 7):

Tips: For more AVS maintenance information, see Recommended Routine ICP-OES and AVS 6/7 Maintenance Schedule

Figure 7. ICP Expert Help