Optical Sensing of Nitrogen, Phosphorus and Potassium: A Spectrophotometrical Approach toward Smart Nutrient Deployment

• Type: Article in International Scientific Journal
• Date: 2019

Authors

Monteiro Silva, F (Author) FCUP; Jorge, PAS (Author) FCUP; Martins, RC (Author) Other

Journal

The Journal is awaiting validation by the Administrative Services.

Title: Chemosensors

Vol. 7

Final page: 51

ISSN: 2227-9040

Indexing

ISI Web of Knowledge - 19 Citations

Scopus - 22 Citations

Other information

Authenticus ID: P-00R-CHT

DOI: 10.3390/chemosensors7040051

Abstract (EN): The feasibility of a compact, modular sensing system able to quantify the presence of nitrogen, phosphorus and potassium (NPK) in nutrient-containing fertilizer water was investigated. Direct UV-Vis spectroscopy combined with optical fibers were employed to design modular compact sensing systems able to record absorption spectra of nutrient solutions resulting from local producer samples. N, P, and K spectral interference was studied by mixtures of commercial fertilizer solutions to simulate real conditions in hydroponic productions. This study demonstrates that the use of bands for the quantification of nitrogen with linear or logarithmic regression models does not produce analytical grade calibrations. Furthermore, multivariate regression models, i.e., Partial Least Squares (PLS), which consider specimens interference, perform poorly for low absorbance nutrients. The high interference present in the spectra has proven to be solved by an innovative self-learning artificial intelligence algorithm that is able to find interference modes among a spectral database to produce consistent predictions. By correctly modeling the existing interferences, analytical grade quantification of N, P, and K has proven feasible. The results of this work open the possibility of real-time NPK monitoring in Micro-Irrigation Systems.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 16