Vapor Generation Accessory VGA–77 Operation manual

VGA–774. Continue the previous step until a consistent response is obtained.When the response is consistent, the system is ready for use.Remember to optimize the operating conditions for your program.Pay particular attention to sample delay, stabilization and rinsetimes.If a consistent response cannot be obtained within a reasonable time,contamination is the likely cause. Even slight contamination of thesystem can suppress production of hydride (or mercury vapor). If thishappens, stop the conditioning procedure and clean the systemthoroughly before continuing. Refer to section 5.1 for VGA cleaninginstructions, and refer to your instrument manual for details oncleaning your ICP.3.2 OperationBefore starting the analytical program you must measure theanalytical signal caused by the presence of analyte in:❏❏The acid and reductant solutions being pumped through thesystemThe analytical blank solution.To do this:1. Place all three uptake tubes in a single container of distilled water.Wait for about 40 seconds to allow the system to stabilize. Performan instrument zero.2. Leave the sample uptake tube in distilled water and place the acidand reductant uptake tubes in their respective reagent solutions.Wait for about 40 seconds and measure the absorbance. Anyabsorbance registered is attributable to analyte in the solutionsbeing pumped through the system.3. Place the sample uptake tube in the analytical blank solution. Waitfor about 40 seconds and measure the absorbance. Thismeasurement is the total absorbance attributable to analyte in allsolutions used (acid, reductant, analytical blank).4. The measurements obtained in the previous two steps allow you todecide whether the blank signal is acceptable or not before usingthe blank solution to calibrate the instrument at analytical zero.You can now calibrate the system and measure your samples.Publication date: May 2004 3-7