same as those in Section 3 except that the concentration of
lead was 5.0mg L−1. In order to select the optimal injection
volume, the absorbance values were plotted versus the injection
volume of the standard organic extract (Fig. 3). The signal
height increased by increasing of the injection volumes up
to about 20L and then remained almost constant. Therefore,
in all the FAAS measurements, volumes of 20L of the
final organic extract were introduced into the flame via a
microsample introduction system.