Application of nanostructure ZnLI₂ complex in construction of optical pH sensor

Abstract

This is for the first time that application of complex nanostructure is reported as pH indicator in PVC matrix. This new optical pH sensor was constructed based on incorporation of ZnLI2 complex nanostructure in PVC matrix. The synthesized nanostructure ZnLI2 complex was characterized by SEM and XRD technique. The membrane solution was speared on the glass plate to provide thin film and the membrane surface morphology was investigated via field emission scanning microscope (FE‐SEM) technique. Central composite design (CCD) combined with desirability function (DF) was applied to find the best experimental composition of membrane providing the highest absorbance. These conditions were found in correspondence with 3 mg of pH indicator, 3 mg of ionic additive and 1.5 mg/mg of DBP/PVC weight ratio. Under optimum conditions, the proposed pH sensor has two linear working ranges of 4 ‐ 8 at 393 nm (R2 = 0.9897) and 5 ‐ 8 (R2 = 0.9982) at 570 nm with response time of 4 min. The pKa of proposed pH optical sensor was calculated through three methods that found to be 5.63. The present optical sensor shows stability after 2 months without any significant divergence in response properties (less than 5% RSD). Furthermore, current pH optode was exhibited good repeatability (RSD = 1.14%) as well as reproducibility (RSD = 4.06%). No significant variation was observed on sensor response with increasing the ionic strength in the range of 0.0–0.5 M of sodium chloride. All above features indicated that the proposed sensor can be successfully used for detection of pH in solutions with different ionic strength.

Recent Advances in Optical, Electrochemical and Field Effect pH Sensors

“…The change in the refractive index increased with OH concentration; thus, the sensor had a higher sensitivity at basic pH values (75.09 nm/pH at pH 11.35). In 2017, a metallic nanostructured complex (ZnLi2) was used in combination with sodium tetraphenylborate, dibutylphthalate, and polyvinyl chloride [49]. This absorbance sensor showed two linear ranges between pH 4 and 8 and between 5 and 8 depending on the wavelength (393 and 570 nm, respectively).…”

Sol-gel process applications: A mini-review

“…This characteristic enables us to produce coating layers consisting of organic molecules, fibers and powders [83,84]. Organic molecules applications in sol-gel composition could be in optics, catalysts and sensors [83,85,86]. These applications are important and as an example, in optics, incorporation of organic molecules dispersed in transparent silicate gels lead to sustaining a higher laser pumping without any photo bleaching in the used dye, compared to the organic polymer matrices.…”

Investigation of Tunable Surface Plasmon Resonances on Spheroid Core–Shell Alloy Nanoparticles Using DDA Method

“…NPs in complex, multilayer, or core-shell nanostructures have attracted significant interest because they can offer additional opportunities for innovation with tailored materials in the fields of physics [6], nanomaterials [7], biomedical nanosystems [8], optical chemical sensors [9], magnetic nanocomposites [10], engineering chemistry [11], photocatalysts [12], solar cells [13], and electrical nanosystems [14]. Among these special structures, the core-shell is a particular class of NPs, consisting of a core and one or several shell layers.…”