Paper Type |
Contributed Paper |
Title |
Flow Injection Amperometric Sensor for Expedient Determination of Orthoshophate in Soil and Water |
Author |
Wisan Chananchana, Jaroon Junsomboon, Manuel Miró and Jaroon Jakmunee* |
Email |
jakmunee@gmail.com |
Abstract: Flow injection amperometric sensor is herein proposed for reliable and expeditious determination
of orthophosphate in terms of phosphorus content (P) in the environmentally relevant samples. The
analytical method is performed by injecting the standard/sample solution into a stream of 0.1 mol L-1
potassium chloride and then merged downstream with 0.5% (w/v) molybdate dissolved in 2.5% (v/v)
sulfuric acid solution to form the intermediate, which is 12-molybdophosphate complex in a reaction
coil. The intermediate was then electrochemically reduced at a glassy carbon electrode (GCE) with
the applied potential of 0.20 V vs Ag/AgCl reference electrode. The reduction of intermediate
produced electrical current that is directly proportional to concentration of orthophosphate in the
injected solution. Linear ranges for determination of orthophosphate are spanned over three ranges
from 10-100 μg P L-1, 0.1-1.0 mg P L-1, and 1-10 mg P L-1, with a detection limit (LOD) of 3 μg P L-1.
Relative standard deviations for 11 replicate injections of both 0.5 mg P L-1 and 5 mg P L-1 were 0.8%.
A sample throughput of 40-60 injections h-1 was achieved. The proposed method was validated by the
analysis of certified reference materials (CRMs) of soil and water, and was successfully applied to reallife
environmental samples. Amperometric detection is a straightforward alternative to the conventional
spectrophotometric one. Besides, this analytical approach does not deteriorate by interferences such
as particulates, colored substances, refractive index effect (Schlieren’s effect). Especially, it can tolerate
concentrations of silicate and chloride as high as 1 g L-1 and 40 g L-1, respectively. |
|
Start & End Page |
301 - 311 |
Received Date |
2020-09-20 |
Revised Date |
|
Accepted Date |
2021-01-14 |
Full Text |
Download |
Keyword |
flow injection, amperometric sensor, molybdate, orthophosphate, water, soil |
Volume |
Vol.48 No.2 (March 2021) |
DOI |
|
Citation |
Chananchana W., Junsomboon J., Miró M. and Jakmunee J., Flow Injection Amperometric Sensor for Expedient Determination of Orthoshophate in Soil and Water , Chiang Mai J. Sci., 2021; 48(2): 301-311. |
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