# Question 5.4: A third spectrophotometric method for the quantitative deter...

A third spectrophotometric method for the quantitative determination of the concentration of $Pb^{2+}$ in blood yields an $S_{samp}$ of 0.193 for a 1.00-mL sample of blood that has been diluted to 5.00 mL. A second 1.00-mL sample is spiked with 1.00 μL of a 1560-ppb $Pb^{2+}$ standard and diluted to 5.00 mL, yielding an $S_{spike}$ of 0.419. Determine the concentration of $Pb^{2+}$ in the original sample of blood.

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Question: 5.13

## The following data were recorded during the preparation of a calibration curve, where Smeas and s are the mean and standard deviation, respectively, for three replicate measurements of the signal. ...

Once again, as you work through this example, reme...
Question: 5.12

## Three replicate determinations are made of the signal for a sample containing an unknown concentration of analyte, yielding values of 29.32, 29.16, and 29.51. Using the regression line from Examples 5.10 and 5.11, determine the analyte’s concentration, CA, and its 95% confidence interval. ...

The equation for a normal calibration curve using ...
Question: 5.11

## Calculate the 95% confidence intervals for the slope and y-intercept determined in Example 5.10. ...

Again, as you work through this example, remember ...
Question: 5.10

## Using the data from Table 5.1, determine the relationship between Smeas and CS by an unweighted linear regression. ...

Equations 5.13 and 5.14 are written in terms of th...
Question: 5.9

## A seventh spectrophotometric method for the quantitative determination of Pb^2+ levels in blood gives a linear internal standards calibration curve for which (SA/SIS)stand = (2.11 ppb^-1) × CA – 0.006 What is the concentration (in ppb) of Pb^2+ in a sample of blood if (SA/SIS)samp is 2.80? ...

To determine the concentration of Pb^{2+}[/...
Question: 5.8

## A sixth spectrophotometric method for the quantitative determination of Pb^2+ levels in blood uses Cu^2+ as an internal standard. A standard containing 1.75 ppb Pb^2+ and 2.25 ppb Cu^2+ yields a ratio of SA/SIS of 2.37. A sample of blood is spiked with the same concentration of Cu^2+, giving a ...

Equation 5.11 allows us to calculate the value of ...
Question: 5.7

## A fifth spectrophotometric method for the quantitative determination of the concentration of Pb^2+ in blood uses a multiple-point standard addition based on equation 5.6. The original blood sample has a volume of 1.00 mL, and the standard used for spiking the sample has a concentration of 1560 ppb ...

To find the x-intercept we let S_{spike}[/l...
Question: 5.6

## Starting with equation 5.6, show that the equations for the slope, y-intercept, and x-intercept in Figure 5.7(a) are correct. ...

We begin by rewriting equation 5.6 as S_{sp...
Question: 5.5

## A fourth spectrophotometric method for the quantitative determination of the concentration of Pb^2+ in blood yields an Ssamp of 0.712 for a 5.00-mL sample of blood. After spiking the blood sample with 5.00 mL of a 1560-ppb Pb^2+ standard, an Sspike of 1.546 is measured. Determine the concentration ...

The concentration of $Pb²^+$ in the o...
To determine the concentration of Pb^{2+}[/...