However, the concentration of PMS in the solution should not exceed [10.sup.-3] mol x [L.sup.-1] because of PMS reduction leading to the residual current increase and
polarogram background line distortions.
In differential pulse
polarogram of control sample with 2 mM ferric iron (in the form of ferric citrate), two peaks appeared respectively at -0.34 V and -0.51 V in comparison with reference electrode.
Another group worked on the rate of hydrolysis of 2 in 40% (vol./vol.) EtOH-Buffer mixture by differential pulse
polarogram. They reported that hydrolysis was catalyzed by H+ and rate follows strictly first-order kinetics.
All the test solution were kept overnight for equilibration before recording
polarograms. Before recording the
polarogram IOLAR grade nitrogen gas (Indian Oxygen Ltd.) was passed through the solution for fifteen minutes.
The choice and concentration of base electrolyte, solvent, initial potential, effect of water addition and interference by other phthalates were the main parameters to optimize for enhancement of peak current and to obtain well-defined
polarogram with lower background current using 1.3 x 10-4 M di-butyl phthalate (DBP) solution.
Figure 4 (a and b) illustrated a series of recorded
polarograms responses with increasing the concentrations of [Cu.sup.2+].
The first category is the statistical methods such as polar plots and
polarograms [11], texture edge statistics onpolarplots [12], moment invariants [13], and feature distribution method [14].
The
polarograms were recorded with a Recorder Polarograph, d.c.
The analysis of lead, given in Figure 2, shows
polarograms corresponding to a range of different lead concentrations found in on electroless nickel bath.