TITLE

Amperometric and spectrophotometric determination of carbaryl in natural waters and commercial formulations

AUTHOR(S)
Portela, Dion�sia C.; Pereira, Isabel M. F.; Pa�ga, Paula; Delerue-Matos, Cristina; Vaz, M. Carmo V. F.
PUB. DATE
September 2003
SOURCE
Analytical & Bioanalytical Chemistry;Sep2003, Vol. 377 Issue 2, p356
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The work presented describes the development and evaluation of two flow-injection analysis (FIA) systems for the automated determination of carbaryl in spiked natural waters and commercial formulations. Samples are injected directly into the system where they are subjected to alkaline hydrolysis thus forming 1-naphthol. This product is readily oxidised at a glassy carbon electrode. The electrochemical behaviour of 1-naphthol allows the development of an FIA system with an amperometric detector in which 1-naphthol determination, and thus measurement of carbaryl concentration, can be performed. Linear response over the range 1.0�10-7 to 1.0�10-5 mol L-1, with a sampling rate of 80 samples h-1, was recorded. The detection limit was 1.0�10-8 mol L-1. Another FIA manifold was constructed but this used a colorimetric detector. The methodology was based on the coupling of 1-naphthol with phenylhydrazine hydrochloride to produce a red complex which has maximum absorbance at 495 nm. The response was linear from 1.0�10-5 to 1.5�10-3 mol L-1 with a detection limit of 1.0�10-6 mol L-1. Sample-throughput was about 60 samples h-1. Validation of the results provided by the two FIA methodologies was performed by comparing them with results from a standard HPLC�UV technique. The relative deviation was <5%. Recovery trials were also carried out and the values obtained ranged from 97.0 to 102.0% for both methods. The repeatability (RSD, %) of 12 consecutive injections of one sample was 0.8% and 1.6% for the amperometric and colorimetric systems, respectively.
ACCESSION #
15124693

 

Related Articles

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sign out of this library

Other Topics