A Co-Nanoparticles Modified Electrode for On-Site and Rapid Phosphate Detection in Hydroponic Solutions.

Feng Xu,Huanqin Wang,Shiyuan Bian,Yuliang Wei,Peng Wang,Deyi Kong

doi:10.3390/s21010299

Abstract

Conventional strategies for determining phosphate concentration is limited in efficiency due to the cost, time, and labor that is required in laboratory analysis. Therefore, an on-site and rapid detection sensor for phosphate is urgently needed to characterize phosphate variability in a hydroponic system. Cobalt (Co) is a highly sensitive metal that has shown a selectivity towards phosphate to a certain extent. A disposable phosphate sensor based on the screen-printed electrode (SPE) was developed to exploit the advantages of Co-nanoparticles. A support vector machine regression model was established to predict the concentration of phosphate in the hydroponic solutions. The results showed that Co-nanoparticles improve the detection limit of the sensor in the initial state. Meanwhile, the corrosion of Co-nanoparticles leads to a serious time-drift and instability of the electrodes. On the other hand, the coefficient of variation of the disposable phosphate detection chip is 0.4992%, the sensitivity is 33 mV/decade, and the linear range is 10−1–10−4.56 mol/L. The R2 and mean square error of the buffer-free sensor in the hydroponic solution are 0.9792 and 0.4936, respectively. In summary, the SPE modified by the Co-nanoparticles is a promising low-cost sensor for on-site and rapid measurement of the phosphate concentration in hydroponic solutions.

Highlights

Phosphate is one of the main nutrients playing many key roles in the human body and plant growth
To address the aforementioned problems, this paper developed a disposable phosphate detection chip with good consistency for a hydroponic solution based on Co-nanoparticles modified carbon screen-printed electrode (SPE), which work without Total ionic strength adjustment buffer (TISAB)
The results show that the time drift of each electrode is large at low concentration and small at high concentration

Summary

Introduction

Phosphate is one of the main nutrients playing many key roles in the human body and plant growth. Phosphorus is an indispensable element in the formation of nuclear protein and lecithin. Phosphorus can accelerate cell division, accelerate root and shoot growth, promote flower bud differentiation, and improve fruit quality [1,2,3,4]. Excessive phosphorus brings many disadvantages to plant growth and development, such as early maturity of crops, small grains, and low yield [5]. The concentration of phosphate needs to be regulated to a balanced and suitable range set, especially in the hydroponic system, all the phosphorus of plants comes from phosphate. The common rapid detection methods of phosphorus content in water can be divide into two categories as follows

Methods

Results

Conclusion