91Ó°ÊÓ

The internal standard equation is $\mathrm{X}={\mathrm{Pb}}^{2+}$and $\mathrm{S}={\mathrm{Cd}}^{2+}$.

The standard mixture response factor is given as

role="math" localid="1667558549294" $$\begin{gathered} \frac{\mathrm{Signal}{}_{\mathrm{X}}}{\left[\mathrm{X}\right]}=\mathrm{F}\frac{\mathrm{signals}{}_{\mathrm{s}}}{\left[\mathrm{S}\right]} \\ \frac{1.58\mathrm{μ´¡}}{[41.8\mathrm{μ²Ñ}]}=\mathrm{F}\left(\frac{1.64\mathrm{μ´¡}}{[32.3\mathrm{μ²Ñ}]}\right) \\ \mathrm{F}=0.7445 \end{gathered}$$

Cadmium mixed with an unknown concentration is

$$\begin{gathered} =\left(\frac{10.00}{50.00}\right)\left(3.23×{10}^{-4}M\right) \\ =6.46×{10}^{-5}M \end{gathered}$$

The concentration of a lead ion in the diluted unknown and undiluted unknown is calculated as

$$\begin{gathered} \frac{\mathrm{Signal}{}_{\mathrm{X}}}{\left[\mathrm{X}\right]}=\mathrm{F}\frac{\mathrm{signals}{}_{\mathrm{s}}}{\left[\mathrm{S}\right]} \\ \frac{3.00\mathrm{μ}A}{\left[P{b}^{2+}\right]}=0.{744}_5\left(\frac{1.64\mathrm{μ´¡}}{[64.6\mathrm{μ}\mathrm{M}]}\right) \\ \left[{\mathrm{Pb}}^{2+}\right]=130.2\mathrm{μ}\mathrm{M} \end{gathered}$$

The strength of undiluted unknown is$\left(\frac{50.00}{25.00}\right)130.2\mathrm{μ}M=2.60×{10}^{-4}M$

Comparative uncertainty in response factor is

$$\begin{gathered} F=\frac{(1.58Â\pm 0.03)(32.3Â\pm 0.1)}{(1.64Â\pm 0.03)(41.8Â\pm 0.1)} \\ =0.7445Â\pm 0.0199(Â\pm 2.67\mathrm{\%}) \end{gathered}$$

Ambiguity in concentration of lead ion is

$$\begin{gathered} \left[{\mathrm{Pb}}^{2+}\right]=\frac{(3.00Â\pm 0.03)\frac{(10.00Â\pm 0.05)}{(50.00Â\pm 0.05)}\left(3.23(Â\pm 0.01)×{10}^4\right)}{(2.00Â\pm 0.03)(0.7445Â\pm 0.0199)} \\ \left[{\mathrm{Pb}}^{2+}\right]=2.60(Â\pm 0.09)×{10}^{4−}\mathrm{M} \end{gathered}$$