Answers to Post-Reading Questions

Chapter 1. Introduction to Chemical Analysis

Question 1

Question 2

Transduction does not produce a voltage or current that is easily related to the quantity of analyte. Calibration establishes an empirical, rather than a theoretical, relationship between the analytical response and the quantity of analyte that caused that response.

Question 3

Limit of detection (LoD): The smallest amount of analyte that can be readily detected.

Dynamic range: The range over which the instrument response changes predictably and significantly with changes in the quantity of analyte.

Sensitivity: The change in signal vs. change in quantity of analyte (e.g. the slope of a linear calibration curve).

Selectivity: The degree to which a method of analysis is sensitive to the analyte versus other species in the sample matrix.

Signal-to-noise (S/N) ratio: The ratio between the average value of the output signal and its variation between replicate measurements.

Signal-to-background (S/B) ratio: The ratio between the average value of the output signal in response to analyte and the output signal in the absence of analyte.

Chapter 2. Properties of Light

Question 1

The photons in the green laser beam have more energy than the photons in the red laser beam because they have a shorter wavelength (i.e. higher frequency).

Question 2

Because the refractive index increases, the wavelength of the red laser beam will be shorter within a BK7 glass lens than through air.

Question 3

No, this observation implies that leaves absorb red light (complimentary to green) most strongly.

Question 4

The angle should be 45°. The angle of incidence equals the angle of reflection, such that 2 × 45° = 90°.

Question 5

Refraction

Question 6

No, the width of the slits needs to be similar in size as the light passing through. Diffraction would not be anticipated until the slit width was on the order of microns.

Chapter 3. Light Sources

Question 1

Question 2