Spectrophotometry

Question 1

What is spectrophotometry?

Answer 1

The method that measures the transmission and absorbance of light by a substance

Question 2

What is spectrophotometry used to measure?

Answer 2

Concentration of; proteins, amino acids, peptides, nucleic acids, nucleotides

Question 3

What methods of measurement are used with a spectrophotometer?

Answer 3

Wavelength scan
- used when analysing an unknown compound
- absorbance is measured at a range of wavelengths
- absorbance is plotted against wavelength
Single wavelength measurement
- absorbance is measured at a fixed wavelength

Question 4

What is the standardised path length of a spectrophotometer?

Answer 4

1cm

Question 5

How many light sources are required in a spectrophotometer?

Answer 5

2

Question 6

What is a photon?

Answer 6

The basic unit of the electromagnetic spectrum at all wavelengths

Question 7

What happens when light is absorbed?

Answer 7

The photons energy is absorbed by / transferred to electrons
The decrease in the number of photons is detected by the spectrophotometer

Question 8

What is the beer lambert law?

Answer 8

The quantity of light absorbed by a substance is directly proportional to the concentration of the substance

Question 9

What causes solutions or materials to be the colour they are?

Answer 9

Wavelengths not absorbed

Question 10

How would you calculate the volume or concentration of a diluted solution?

Answer 10

C1 x V1 = C2 x V2