Construção e aplicação analítica de eletrodos de pasta de carbono modificada com ftalocianina de cobalto para determinação de analítos de interesse.
Fecha
2004-04-16Autor
Conceição, Cleone das Dores Campos
Metadatos
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In this thesis work the development and applications of cobalt
phthalocyanine carbon paste electrode (CoPc/CPE) for voltammetric determination
(cyclic voltammetry and differential pulse voltammetry) of hydrazine in boiler feed
water, dopamine, vitamin B1 (thiamine) and vitamin B6 (pyridoxine) in pharmaceutical
preparations available commercially in the market, without any previous treatment of
the samples. The CoPc/CPE presented voltammetric response (for cyclic
voltammetry and differential pulse voltammetry) linear in the hydrazine concentration
range from 1,3x10-4 to 9,8x10-4 mol L-1, with detection limit of 3,0x10-5 mol L-1 and
5,0x10-5 to 7,4x10-4 mol L-1, with detection limit of 2,3x10-5 mol L-5, respectively. The
hydrazine quantification in waters of boilers using CoPc/CPE presented results of
agreement with the spectrophotometric method with an interval of acceptable relative
error. The CoPc/CPE presented a voltammetric response (for cyclic voltammetry and
differential pulse voltammetry) linear in the dopamine concentration range from
1,3x10-5 to 2,8x10-4 mol L-1, with detection limit of 1,0x10-5 mol L-1e 5,0x10-6 to
9,8x10-5 mol L-1, with limit of detection of 1,4x10-6 mol L-1, respectively. That modified
electrode presented good performance as voltammetric sensor in the dopamina
determination in pharmaceutical preparations. The CoPc/CPE presented an
voltammetric response (differential pulse voltammetry) linear in the vitamin B1
(thiamine) concentration range from 5,0x10-5 to 3,8x10-4 mol L-1, with detection limit
of 2,5x10-5 mol L-1. The thiamine quantification in pharmaceutical formulations using
CoPc/CPE presented results of agreement with the spectrofluorimetric method of
Brazilian Pharmacopeia s with an interval of acceptable relative error. CoPc/CPE
presented an voltammetric response (for cyclic voltammetry and differential pulse
voltammetry) linear in the vitamin B6 (pyridoxine) concentration range from 5,0x10-5
to 9,8x10-4 mol L-1, with detection limit of 4,7x10-6 mol L-1 and 5,0x10-5 to 3,4x10-4 mol
L-1, with detection limit of 1,3x10-6 mol L-1, respectively. That modified electrode
presented good performance as voltammetric sensor in the pyridoxine determination
in pharmaceutical preparations. The CoPc/CPE was also used in the simultaneous
determination of vitamins B1 (thiamine) and B6 (pyridoxine) by differential pulse
voltammetry, in pharmaceutical preparations, once the oxidation peaks potentials of
the vitamin B1 (-0,13 V) and vitamin B6 (0,55V), healthy very different. The analytic
curves were linear in the interval of thiamine concentration of 1,9x10-4 to 7,4x10-4 mol
L-1, with limit of detection of 8,4x10-5 mol L-1 and of 1,0x10-4 to 7,4x10-4 mol L-1, with
limit of detection of 1,5x10-5 mol L-1 for pyridoxine. That modified electrode presented
satisfactory acting as voltammetric in the determination of both in pharmaceutical
preparations.