Determination of arylsulphatase and phosphatase enzymes activities in soil using screen printed electrodes modified with multi-walled carbon nanotubes.

PATRICIA W. STEGE; GERMÁN A. MESSINA; GUILLERMO BIANCHI; ROBERTO A. OLSINA; JULIO RABA

SOIL BIOLOGY AND BIOCHEMISTRY

Elsevier

Lugar: Amsterdam; Año: 2009 vol. 41 p. 2444 - 2452

0038-0717

<!-- /* Font Definitions */ @font-face {font-family:Batang; panose-1:2 3 6 0 0 1 1 1 1 1; mso-font-alt:바탕; mso-font-charset:129; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1342176593 1775729915 48 0 524447 0;} @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:"@Batang"; panose-1:2 3 6 0 0 1 1 1 1 1; mso-font-charset:129; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1342176593 1775729915 48 0 524447 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Sustainability of agricultural systems has become an important issue all over the world. The activity of enzymes is one of the most important quality bioindicator in soil. The aim of the present study was the development of a simple and convenient assay to determine the activity of arylsulphatase (AS), acid (ACP) and alkaline phosphatase (ALP) in agricultural soil. The activities of these enzymes were detected using non-electroactive substrate, which produces an electroactive product. The p-aminophenyl phosphate (pAPP) was used as a substrate and it was converted to p-aminophenol (pAP) after the enzymatic dephosphorylation. The 4-nitrocatechol sulfate (4-NCS) was used as a substrate for AS activity based on it catalytic effect on the hydrolysis of 4-NCS into 4-nitrocatechol (4-NC). The products of both enzymatic reactions were quantified on carbon-based screen-printed electrodes (SPCEs) modified with carbon nanotubes (CNTs) using Osteryoung square wave voltammetry (OSWV). The determination of the reaction products allowed more sensitive determination of ALP, ACP and AS activities in soil than that obtained with the spectrophotometric method. This assay was performed in order to diminish the generation of waste, which is an important requisite in green analytical chemistry. The optimization of the analytical procedure in terms of the nature of electrode type, applied potential, pH of solution, and precision of measurements was studied.