International Journal of Science and Technology

International Journal of Science and Technology>> Volume 7, Number 9, September 2017

International Journal of Science and Technology

Spectrophotometric Determination of Fe (III), Fe( II) and S2O4-2 Ions in Aqueous Solutions by using Tetra Sodium Meso Tetra (P-Sulfophenyl ) Porphine as a Ligand

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Author Jihad A. Taies , Noor Mohammed
On Pages 101-107
Volume No. 3
Issue No. 1
Issue Date January, 2013
Publishing Date January, 2013
Keywords Tetra (4-sulfophenyl) porphyrin ; Iron spectrophotometry


In this paper , the complex reaction of water - Soluble meso -tetra (4-Sulfophenyl) porphyrin (TPPS4) with Fe( III) ion has been studied in the presence of small amount of hydroxyl amine . The porphyrin was found to be a highly sensitive and highly selective reagent for direct spectrophotometric determination of iron at g level .The soret band of the complex lay at 394 nm (: 3.88 x 105L.M-1cm-1 ) , which is well separated from that of the reagent 432 nm ,( = 2.2 x 105 L.M-1. Cm-1) below PH 2The complex formation is slow at room temperature and PH 5.0 , however , it can be accelerated by heating on boiling water bath and completed within 10 min at 100 Co . five determinations of standard solutions containing 0.7 mg /10mL of iron gave a relative standard deviation of 2.61%. Beer's law is obeyed for iron (III) in the range of 0.01-2.0 g/10ml . The molar ratio of complex is 1:1. This method has been applied to determine iron (III) in water samples with satisfactory results. The complex is highly stabie .The interference of many ions and salts have been examined and found to be minimal . Large amounts of rare earth do not interfere with the determination . The complex reaction of Fe (III ) TPPS with reducing agent of Na2S2O4 was studied as well, it was found the reaction is time dependent ,and the reduction can be completed within 6 min . The soret band of Fe TPPS at PH=12.5 lay at 408 nm but in the presence of sodium dithionite moves to long wave length of 438 nm that assign of Fe(II) TPPS.The reduction was take place at room temperature, however it can be used this reaction to determine the S2O4-2 ion in aqueous solutions or solids . Beer's law is obeyed for S2O4-2 in the range of 0.01-1.85 mg/10ml and the molar absorptivity of Fe (II ) TPPS is 3.48 x 105 L.M-1, Cm-1 ,and ,for S2O4-2 is 1.47x 103 L.M-1,Cm-1.Five determinations of standard solutions containing 3.52 mg /10ml of Na2S2O4gave a relative standard deviation of 0.315 .The interference of lactose, starch and sodium chloride was found effective.The recovery percentage was in the range of 87.5 -98.29 % and the RSD% in the range of 0.57-1.28 (n=3) .Also in this paper the determination of Fe (II ) in Fe (III) TPPS was studied by reduction the Fe( III) TPPS complex at PH 6.5 by using Na2S2O4 in the presence of bipyridyl reagent, it has been found the reagent destroy the porphyrin ring and Fe(II) ion come out of ring and react directly with bipyridyl reagent due to steric effect, the amount of Fe (II ) equal to the third amount of bipyridyl moles react with Fe(II ) ion to from a new red complex of Fe(bipy)3 with soret band lay at 522nm and (= 30 L.M-1.Cm-1)Beer's low obeyed for Fe(II)in the range of 0.01-15.6 mg/10ml. Moler ratio was found 3:1 bipyridyl to Fe( II )ion The sensitivity For the 0.001 absorbance sendell's index was 0.00014, 0.087 and 1.8 For Fe(???), S2O4-2 and Fe(??) respectively . This method can be used to determine the Fe( II ) ion in hemoglobin.

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