Beer Lambert

Question 1

Transmittance (T)

%T

Answer 1

T = I/Io

is the fraction of incident light which is transmitted, the amount of light that passes through the substance and comes out the other side.

It is defined as T = I/Io, where I = transmitted light (“output”) and Io = incident light (“input”).

%T= 100 x T

Question 2

Absorbance formula

Answer 2

A = log (1/T)

Question 3

Work out transmittance when given absorption

Answer 3

T = 10 to the minus A

Question 4

Beer lambert formula

Answer 4

A=εcl

ε = molar absorptivity L per mole per centimetre
l = 1cm
c = concentration

Question 5

Acceptable absorbance values

Answer 5

Between zero and one

Question 6

Relationship between millimetres and centimetres?

Answer 6

I cm = 10 mm

Question 7

Relationship between grams and milligrams

Answer 7

1 g = 1000 mg

Question 8

What is 10 mm in cm?

Answer 8

1 cm

Question 9

Units of molecular mass

Answer 9

Grams per mole

Question 10

To work out molar absorption coefficient?

Answer 10

Use the beer lambert law, concentration must be in moles per litre

Convert your units of concentration to moles per litre, usually involves using the molar mass formula

Question 11

Internal standard calibration curve

Answer 11

Peak Area A / Peak Area B vs Concentration A

Question 12

Beer lambert law is a plot of

Answer 12

Absorbance versus concentration

Question 13

Dealing with a diluted sample and a calibration curve eg a sample has 1:5 dilution has a concentration of 3ppm. What is the concentration ?

Answer 13

3ppm x 5 = 15 ppm

Question 14

Graph of concentration v emission intensity

Answer 14

Emission is equivalent to absbance

Plot : emission v concentration

Create a best fit line

Use best fit line to find concentration and account for any dilution