Troubleshooting and Maintenance of AA Systems: Part 3- Graphite Furnace Optimization

This Information Applies To: Agilent Graphite Furnace Atomic Absorption and Zeeman Instruments (240/280(Z) AA)

Issue:

How to optimize the Instrument to allow for better results, troubleshooting, after maintenance or lamp replacement.

Steps to follow:

Warning: The furnace runs at temperatures up to 3000 degree Celsius. Allow furnace to cool completely before touching.

Optimize one or more lamps: 

Lamp optimization is required after cleaning or installing a new lamp or used lamp. Lamp optimization can identify when a lamp has reached the end of its working life. 

1. Remove the furnace workhead from the light path before optimizing the lamps: 
   1. Tilt the Zeeman workhead forward, or

   2. Release the GTA thumbscrew (Figure 3) and remove the workhead. 

2. Load a method and select Optimize button > OK to open the Furnace Optimization window. While watching the green Gain % bar (Figure 1), adjust the two knobs at the base of the HCL lamp (Figure 2).

   
   Figure 1. Lamp Optimization
   
   Figure 2. Hollow Cathode Lamp Adjustment

3. The lamp is optimized when the intensity (green bar) is in scale and at the highest point. If the bar is green to the top, select Rescale and continue optimizing. Once the lamp is fully optimized, record the Gain % value. 

   Tips: Each time the lamp is optimized the Gain % value will be close to the previous value and the original value. A significant difference indicates that the lamp is near or at the end of its life. See Troubleshooting and Maintenance of Atomic Absorption Systems: Part 1 - Hollow Cathode Lamps - YouTube

4. Move the workhead back into the light path: 

   1. Tilt the Zeeman workhead backwards, or

   2. Replace the GTA workhead and lock down the thumbscrew (Figure 3). 

      
      Figure 3. Furnace Workhead Adjustment. 1 GTA thumbscrew location 2 Horizontal adjustment knob 3 Vertical adjustment knob

5. While watching the green Gain % bar (Figure 1), optimize the horizontal and vertical position of the workhead using the appropriate knob (Figure 3). The workhead is position is optimized when the intensity (green bar) is in scale and at the highest point. The vertical and horizontal adjustments can be performed in any order:

6. Turn on the water chiller/exchanger and argon gas supply.

7. Replace the Agilent Programmable Sample Dispenser / Autosampler (PSD) on the front of instrument with the two hooks in sample compartment. Tighten the alignment block on the right side of the PSD-120. Align the PSD. See Alignment of the Sample Probe on the Agilent PSD 120. 

8. Monitor the injection of a blank solution and calibration standard. The absorbance valus for the blank (less than 0.01 Abs) and standard should return to normal operating conditions. 

Learn how to effectively operate your Agilent Atomic Absorption System: Troubleshooting and Maintenance of Atomic Absorption Systems: Part 3 - Graphite Furnace AAS YouTube Agilent 240/280 Series AA User's Guide manual on Agilent.com