Vapor Generation Accessory VGA–77 Operation manual

VGA–773.1.3 AA setup1. Remove the cell in its holder from the burner and place it at thefront of the reagent module.2. Lower the burner using the burner height controls so that it isclear of the optical path.✒ Note Varian recommends using reduced slit height (0.5) in all methods.3. Fit the required hollow cathode lamp and set up the spectrometeras described in your instrument operation manual.4. Select Optimize, then Optimize Lamp.5. Position the cell in its holder on top of the burner.6. Align the cell in the optical path as follows:i. Hold a piece of white card between the right-hand end of theabsorption cell and the sample compartment window.ii. Using the burner positioning controls, adjust the position ofthe cell until the light from the hollow cathode lamp passesthrough the cell onto the card. Remove the card.iii. Use the burner positioning controls to adjust the position ofthe cell for maximum transmission.For mercury determinations, proceed to ‘Conditioning the system’.-JHIUJOHÁUIFÁGMBNFÁ1. Carry out any safety checks described in your spectrometeroperation manual. Follow all instructions and observe allwarnings.2. Set the acetylene flow rather higher than normal in order toobtain a fuel-rich air-acetylene flame, this is required for theigniting the flame.✒ Note Some instruments may automatically set a fuel-rich mixture. Youshould refer to your spectrometer operation manual for details.WarningWith the VGA-77 cell installed, the burner will be lower than usual,and a standard mixture or a fuel-lean mixture may not ignitereadily. To avoid an explosive accumulation of fuel and oxidant inthe sample compartment, ALWAYS ensure that the gas mixture isfuel-rich before operating the Ignite button.3-4 Publication date: May 2004