Question

Use the following information and the Beer-Lambert law to determine the mass of the lycopene extracted and the mass of lycopene per 100 grams of tomato paste.

2mL of lycopene was extracted from 8 grams of tomato pase. This was then diluted to 5mL. 1ml of the diluted solution was withdrawn and then further diluted to 9mL. The UV-vis absorbance at 502nm was determined to be 0.162. The cell path was 1cm.

Answer 1

The general Beer-Lambert law is usually written as: A = a( ) * b * c. where A is the measured absorbance, a( ) is a wavelength-dependent absorptivity coefficient, b is the path length, and c is the analyte concentration.

here   putting values     0.162   = 502*10^-9*1*10^-2*c

                                   because here A = .162 (given)

                                                          a = 502 nm =502*10^-9

                                                            b = 1 cm = 10^-2 m

                          Fromwhere , after calculations c = 3.23^10^7

This result has come from dilution 2 ml to 5ml then 1 ml to 9 mlthat is diluting 5/2*9/1 =45/2 times

so originally   c* 2/45 times lycopene was present = 3.23*10^7 *2/45 = 1.435*10^3 in 8 grams

                                                                          = 1.435* 10^3 * 100/8 = 17.9375 ml    from where mass of lycopene can be calculated

From whe