[sramesrame]

Dear All,
         
          Any one kindly help me in the anaylsis of lead in water/food samples by AAS-graphite furnace.
In the lead by GFAAS, what is the ashing &atomise temperature. And which modifier is suitable. b'cos i get the linear curve in standards, standard checks but i did not able to detect the samples.
I am using 217 nm wavaelength. Ashing and atomise temp are 800& 1200dgree C respectively.

[kevins]

Please try the standard addition method (it may check the sample contains lead or not) and I suggest try to ramp the temperature from dry temperature (say 150C) to the ashing temperature (800C) for 30 sec. to avoid the sudden boiling of water sample.

[ozonoyo]

I use the following parameters in a AA Hitachi Z-5000.
I set up the method for water and wastewater according method EPA 7421 (download it from SW846-online section in EPA page).
We adjust some parameters from the method.

Lamp current : 9mA
Wavelenght : 283.3nm
Carrier gas (Ar): 30mL/min
Sample volume : 20ul

Drying : 80 to 140ºC in 40 sec (ramp)
Ashing : 600ºC in 20 sec
Atomizing : 2400ºC 5sec
Cleaning : 2700ºC 4sec

We use calibration curve from 0 to 30 ppb