Flame Optimization for Agilent Atomic Absorption Systems

Answer

This Information Applies To: Agilent Flame Atomic Absorption (AA) Spectrometers (50/55/240/280 AA)

Issue:

How to optimize the Agilent Flame AA for better instrument performance and response stability

Steps to follow:

Use Figure 1 as reference for the procedure on the Flame AA optimization.

Figure 1. Agilent Flame AA instrument diagram

Tips: Steps 1 through 4 are performed with the flame off in the Optimization Page of SpectrAA by selecting Optimize Lamps

Figure 1. Lamp Optimization Page

• Optimize the Lamp
  1. Adjust the two control knobs at the base of the HCL lamp while watching the green bar
  2. If the bar peaks at the top (as shown in Figure 1) select Rescale
  3. Once the lamp is fully optimized (Gain % value shown is close to the expected value for the element), Record the Gain % number for your records.

Tips:See Troubleshooting and Maintenance of Atomic Absorption Systems: Part 1 - Hollow Cathode Lamps - YouTube for more detailed information

Tips: See What are the typical % Gain or EHT values for hollow cathode lamps? | Agilent for estimated Gain % values

• Adjust the Burner vertically
  
  1. Place the Burner Alignment Card (Agilent business type card with circle) in the center of the burner (Figure 2)
  2. Attempt to line up the light from the lamp to the X in the center of the circle on the card by using the inner, smaller knob on the front of the instrument to raise or lower the light as needed
  3. Once the light from the lamp is centered as best as possible on the X marking, move to the next step

Figure 2. Vertical Alignment of Burner

• Adjust the Burner horizontally
  
  1. As in the previous step, place the Burner Alignment Card in the center of the burner (Figure 2)
  2. Attempt to line up the light from the lamp to the X in the center of the circle on the card from one end of the burner to the other
  3. To move the burner horizontally, use the outer-most, wider knob on the front of the instrument. See Figures 3 through 5
  4. Once the light from the lamp is centered as best as possible on the X marking while moving across the burner slot, move to the next step

Figure 3. Horizontal Adjustment Control

 Figure 4. Alignment of Lamp light on one side of burner

 Figure 5. Alignment of Lamp light across Burner slot

• Adjust the Burner rotationally
  
  1. As in the previous step, place the Burner Alignment Card in the center of the burner (Figure 2)
  2. Attempt to line up the light from the lamp to the X in the center of the circle on the card from one end of the burner to the other
  3. To rotate the burner use the silver handles on the front of the burner (Figure 4)
  4. Rotate the burner until the light is in the center of the circle of the card while moving it across from one end to the other
  5. Once the light is in the center of the circle of the card at both ends, move to the next step

Tips: See Troubleshooting and Maintenance of Atomic Absorption Systems: Part 2 - Flame Atomic Absorption - YouTube for more detailed information

Tips: The following steps are performed with the Flame On in the Optimization Page and select Optimize Signal

Warning: Once the flame is on, keep loose articles and hands away to avoid serious burns.  Burner will be hot.

• Adjust the nebulizer uptake rate
  
  1. Fill a graduated cylinder with DI water (Figure 6)
  2. Measure the uptake rate for one minute
  3. The value should be 5 to 6 mL/min
  4. If the value is not correct, adjust the barrel of the nebulizer (Figure 7) counterclockwise to speed up, and clockwise to slow down the rate
  5. Repeat these steps until 5 to 6 mL/min is observed

Figure 6.  Graduated Cylinder with DI water 

 Figure 7.  Nebulizer Rate adjustment 

• Adjust the Glass Bead
  
  1. On the Optimize Signal page, select Instrument Zero with DI water aspirating
  2.  Select a mid to high level standard of an element.  Copper is preferred.
  3. Aspirate a mid to high level standard of the element while observing the blue signal bar rising (Figure 8)
  4. The value should be 5 to 6 mL/min
  5. Turn the glass bead adjustment screw (Figure 9) completely clockwise
  6. Watch for the signal to decrease, then turn the screw counterclockwise finding the peak in the signal
  7. The glass bead is now fully optimized

 Figure 8.  Optimize Signal and blue signal bar 

Figure 9.  Glass Bead adjustment

• Adjust the Fuel setting
  
  1. As in the previous step on the Optimize Signal page, select Instrument Zero while aspirating a mid to high level standard of an element (Copper is preferred)
  2. Observe the blue signal bar rising as in the previous step (s).
  3. Begin by adjusting the red arrow up or down on right side of the page (Figure 10) or turning the acetylene handle on the front of the instrument 
  4. Maximize the blue bar signal by adjusting this fuel flow to the best setting, using the blue bar as a guide

Figure 10. Fuel Adjustment 

Tips: See Troubleshooting and Maintenance of Atomic Absorption Systems: Part 2 - Flame Atomic Absorption - YouTube for more detailed information

Confirmation: Optimization is now complete

Tips: If using SIPS, start the pump tube conditioning program and complete the bubble test to confirm that an air bubble is moving towards the instrument. This procedure verifies that no clogs are present and that the nebulizer uptake is at least 5 mL/min