Brazilian Journal of Analytical Chemistry - BRJAC - Brazilian Journal ...

Br J Anal Chem 2011, 03, 158–163
a m u l t iC o m m u t a t E d f l o w systEm f o r PEraCEtiC aCid
d E t E r m i n a t i o n
fa B í o l a so ra i a vi t a l Ca m P o s BarBosa d a silva a,B , Jo i l t o n Jo s é d a silva Jú n i o r a , an d ré fE r n a n d o la v o ra n t E C , an a Pa u l a silvEira
Pa i m a *
A) Departamento de Química Fundamental – Universidade Federal de Pernambuco, Av. Jornalista Aníbal Fernandes, s/nº. CEP 50.740-560 – Recife,
PE, Brazil.
B) Instituto Federal de Educação, Ciência e Tecnologia de Pernambuco. Av. Prof Luiz Freire, 500. 50740-540 – Recife, PE, Brazil.
C) Universidade Federal Rural de Pernambuco – Departamento de Química, Rua Dom Manoel de Medeiros, s/n. 52171- 900 – Recife, PE, Brazil.
* Corresponding author:
anaspaim@ufpe.br;
paulapaim@pq.cnpq.br
Phone: +55 81 2126 7469.
aBstraCt
Peracetic acid (PAA) has been used as a pre-disinfectant in water supplies to improve the
quality of raw water, reducing the amount of pathogens and the formation of chlorinated
byproducts. A rapid analytical procedure is desirable for the analysis of PAA, since
its diluted solutions are unstable. A flow procedure based on a multicommuted flow
injection analysis process (MCFIA) to determine PAA is proposed. The method is based
on the reaction of PAA with an iodide solution liberating iodine. The liberated iodine
oxidizes the DDPD (the methyl-substituted form of N, N-diethyl-p-phenylenediamine)
with the use of a commercial kit, Vacu-vials ® (CHEMetrics, Inc). The compound was
monitored at 565 nm. Three solenoid micro-pumps were used to insert samples of the
carrier solution (water) and reagent (kit Vacu-vials ® ). The linear response ranged from
0.5 to 5.0 mg L -1 PAA (R = 0.9995). The coefficient of variation was estimated as 4.0
% (n = 8) for a sample of 3 mg L -1 PAA. The detection and quantification limits were
0.10 mg L -1 and 0.33 mg L -1 , respectively. The sampling throughput of 80 determinations
per hour consumed 80 µL of reagent solution (this volume is 25 times smaller than
the volume used in bench scale measurements with a kit) and a waste generation of
1.50 mL per determination.
kE y w o r d s: Multicommutation flow analysis; Peracetic acid; Disinfectants; Spectrophotometry
1. In t r o d u c t Io n
Peracetic acid (ethaneperoxoic acid, PAA) was patented
in 1950 by Greenspan and Margulies for treating
fruit and vegetables to reduce spoilage from bacteria
and fungi [1]. The technical synthesis of PAA comprises
a reaction of hydrogen peroxide with acetic acid in the
presence of a strong mineral acid, typically sulphuric
acid, as a catalyst [2,3,4]
PAA is efficient at low concentrations against a broad
spectrum of microorganisms, including gram-positive
and gram-negative bacteria, yeasts, molds and algae
under a wide variety of conditions [4,5]. It is an important
oxidant in industrial processes, such as for disinfection
in breweries and dairies, for the bleaching of paper
and textiles, and in the sterilization of medical instruments
[6]. Due to its bactericidal, virucidal, fungicidal
and sporicidal effectiveness, the use of PAA as a disinfectant
for wastewater effluents has recently been attracting
attention [7-9]. PAA has been tested and used
for wastewater disinfection in England, Finland, Italy,
Brazil and Canada [9].
In addition, it is well-known that PAA is a more efficient
oxidant and disinfectant than chlorine or chlorine
dioxide [9]. In drinking water the utilization of this acid
is reported as a prior-disinfectant to improve the quality
of water, reducing the quantity of pathogens and the
potential formation of chlorine by-products when chlorine
is used as disinfectant [10]. Chlorine is maintained
as a secondary disinfectant only to maintain residual
disinfectant.
The advantages for wastewater disinfectation are:
ease of implementing treatment, a broad spectrum of
activity even in the presence of heterogeneous organic
matter, the absence of persistent toxic or mutagenic residuals
or by-products, and the no quenching requirement
(i.e., no dechlorination), little dependence on pH
and a short contact time [9].
158 Br J Anal Chem