Determination of Unknown Concentration of Iron in the Given Juice Sample by Spectrophotometric

Determination of unknown concentration of Iron in the given juice sample by spectrophotometric method

Preparation of Solutions

a)0.1% 1-10-phenonthroline solution of 100ml volume

To prepare 0.1%solution of 1-10-phenonthroline of 100ml volume dissolve 0.1g of 1-10-phenonthroline in distilled water and dilute it upto the mark with distilled water using 100ml volumetric flask.

b)100ppm Iron Solution of 100ml volume

To prepare 100ppm solution of iron of 100ml volume dissolve 0.07g of Fe(NH4)2(SO4)2.6H2O salt in distilled water and also add 2ml of concentrated H2SO4 and then dilute it upto the mark with distilled water using 100ml volumetric flask.

c)10% hydroxylamine hydrochlorideSolution of 100ml volume

To prepare 10% solution of hydroxylamine hydrochloride, dissolve 10g of hydroxylamine hydrochloride in distilled water and dilute it upto the mark with distilled water using 100ml volumetric flask.

d)0.1N CH3COONa Solutions of 100ml volume

Dissolve 0.82g of CH3COONa saltin distilled water and dilute it upto the mark with distilled water using 100ml volumetric flask.

e)0.1N CH3COOH Solutions of 100ml volume

Dissolve 0.57ml of CH3COOHin distilled water and dilute it upto the mark with distilled water using 100ml volumetric flask.

f) Buffer solution of pH5

To prepare a buffer solution of pH5 mix 65ml of 0.1Nacetic acid solution and 35ml of 0.1Nsodium acetate solution in a 100ml volumetric flask.

Procedure

Prepare working standard solutions of 1, 3, 5, 7, and 9ppm from 100ppm stock solution by taking 1, 3, 5, 7, and 9ml volume from 100ppm stock solution in a100ml volumetric flasks. To each of the standard solution add 1ml of 10% hydroxylamine hydrochloride solution to convert any Fe3+ into Fe2+ by reduction. Similarly to each standard solution also add 10ml of pH5 buffer and add 5ml of 0.1% of 1-10-phenonthroline solution. Allow the standard solutions to stand for 30minutes and then dilute with distilled water using 100ml volumetric flasks.

Blank Solution

Blank solution can be prepared by adding 1ml of 10% hydroxylamine hydrochloride Solution, 10ml of pH5 buffer solution and 5ml of 0.1% 1-10-phenonthroline solution and then diluting with distilled water using 100ml volumetric flasks.

Sample Solution Preparation

To prepare a juice sample solution takes 70ml of apple juice in a beaker. To remove the color from apple juice add 1g of activated charcoal to it and then stirrer it with glass rod and then filter with filter paper. To the filtrate then add 1ml of 10% hydroxylamine hydrochloride solution, 10ml of pH5 buffer solution and 5ml of 0.1% 1-10-phenonthroline solution and then dilute with distilled water using 100ml volumetric flasks. Measure the absorbance of all solutions at 510nm using spectrophotometer.

EXPERIMENT

Determination of formula and stability constant of a complex by using Spectrophotometric method

Preparation of Solutions

f)5x 10 -4 M Solution of 1-10-phenonthroline of 250ml volume

To prepare 5x 10 -4M Solution of 1-10-phenonthroline of 250ml volume dissolve 0.022g of 1-10-phenonthroline in distilled water and dilute it upto the mark with distilled water using 250ml volumetric flask.

g)5x 10 -4 M Solution of Iron of 250ml volume

To prepare 5x 10 -4M solution of iron salt of 250ml volume dissolve 0.049g of Fe(NH4)2(SO4)2.6H2O in distilled water and dilute it upto the mark with distilled water using 250ml volumetric flask.

h)5% hydroxylamine hydrochlorideSolution of 100ml volume

Dissolve 5g of hydroxylamine hydrochloride in distilled water and dilute it upto the mark with distilled water using 100ml volumetric flask.

i)0.1N CH3COONa Solution of 100ml volume

Dissolve 0.82g of CH3COONa saltin distilled water and dilute it upto the mark with distilled water using 100ml volumetric flask.

j)0.1N CH3COOH Solution of 100ml volume

Dissolve 0.57ml of CH3COOHin distilled water and dilute it upto the mark with distilled water using 100ml volumetric flask.

Procedure

Put iron and 1-10-phenonthroline solutions in a five different 100ml volumetric flasks in the following proportion given as below

Vml of metal (Iron solution
(5x 10 -4M) / 1 / 2 / 3 / 4 / 5
Vml of ligand (1-10-phenonthroline solution
(5x 10 -4M) / 9 / 8 / 7 / 6 / 5

Also add 1ml of 5% hydroxylamine hydrochloride and 10ml of buffer solution of pH 5 (65ml of 0.1N CH3COOH and 35ml of 0.1N CH3COONa ) to each flask and dilute each solution upto the mark with distilled water.

Allow all the solutions to stand for 10min and then measure the absorbance of each solution at 510nm using UV-Visible spectrophotometer.

Also plot absorbance on graph paper to find the formula and stability constant values.