scholarly journals An All-Solid-State Nitrate Ion-Selective Electrode with Nanohybrids Composite Films for In-Situ Soil Nutrient Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2270
Author(s):  
Ming Chen ◽  
Miao Zhang ◽  
Xuming Wang ◽  
Qingliang Yang ◽  
Maohua Wang ◽  
...  

In this paper, an all-solid-state nitrate doped polypyrrole (PPy(NO3−) ion-selective electrode (ISE) was prepared with a nanohybrid composite film of gold nanoparticles (AuNPs) and electrochemically reduced graphene oxide (ERGO). Preliminary tests on the ISE based in-situ soil nitrate–nitrogen (NO3−-N) monitoring was conducted in a laboratory 3-stage column. Comparisons were made between the NO3−-N content of in-situ soil percolate solution and laboratory-prepared extract solution. Possible influential factors of sample depth, NO3−-N content, soil texture, and moisture were varied. Field-emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) characterized morphology and content information of the composite film of ERGO/AuNPs. Due to the performance excellence for conductivity, stability, and hydrophobicity, the ISE with ERGO/AuNPs illustrates an acceptable detection range from 10−1 to 10−5 M. The response time was determined to be about 10 s. The lifetime was 65 days, which revealed great potential for the implementation of the ERGO/AuNPs mediated ISE for in-situ NO3−-N monitoring. In-situ NO3−-N testing results conducted by the all-solid-state ISE followed a similar trend with the standard UV-VIS method.

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 525
Author(s):  
Rongrong Wu ◽  
Xue-Gang Chen ◽  
Chunhui Tao ◽  
Yuanfeng Huang ◽  
Ying Ye ◽  
...  

Ion-Selective Electrode (ISE) is an emerging technology for in situ monitoring of the chemical concentrations of an aqueous environment. In this work, we reported a novel all-solid-state silicate ISE, using an Ag/Pb/PbSiO3 electrode. This electrode responded to aqueous SiO32− with a reasonable slope of −31.34 mV/decade and a good reproductivity. The linear range covered from 10−5 M to 10−1 M, for the Na2SiO3 solutions and the response time was generally less than 5 s. Its potentiometric response to pH and silicate indicated that the prepared electrode was sensitive to silicate, rather than pH. Compared to the traditional liquid ISE, our all-solid-state silicate electrode was resistant to high pressure and could be used in situ, in deep water. In addition, the miniaturized electrodes (diameter of 0.4 mm and a length of 2–3 cm) could be easily integrated into a multi-modal sensor, which could simultaneously determine multiple parameters. Our prepared silicate ISE could potentially be used to determine the presence of silicate in a low-chloride aqueous environment, where the ISE exhibited better selectivity for silicate, over interfering ions such as, SO42−, NO3−, CH3COO−, CO32−, and PO43−.


Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2869
Author(s):  
Cecylia Wardak ◽  
Karolina Pietrzak ◽  
Małgorzata Grabarczyk

A new copper sensitive all solid-state ion-selective electrode was prepared using multiwalled carbon nanotubes-ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) nanocomposite as an additional membrane component. The effect of nanocomposite content in the membrane on the electrode parameters was investigated. The study compares, among others, detection limits, sensitivity, and the linearity ranges of calibration curves. Content 6 wt.% was considered optimal for obtaining an electrode with a Nernstian response of 29.8 mV/decade. An electrode with an optimal nanocomposite content in the membrane showed a lower limit of detection, a wider linear range and pH range, as well as better selectivity and potential stability compared to the unmodified electrode. It was successfully applied for copper determination in real water samples.


1971 ◽  
Vol 54 (4) ◽  
pp. 760-763
Author(s):  
William L Hoover ◽  
James R Melton ◽  
Peggy A Howard

Abstract A method for determining low levels of iodide in feeds and plants is proposed. The samples are mixed with a 10% phosphate solution to maintain relatively constant ionic strength and pH and analyzed with a solid-state iodide electrode. Ashing is not required and there are no significant interferences by ions commonly found in feeds. The method is accurate in determining iodide content ranging from 10.0 ppm to high concentrations. Necessary conditions for storing and cleaning the electrodes are described. The proposed method is rapid and results compare favorably with AOAC method 7.091.


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