Designing an optical sensor with exceptional sensitivity and specificity for the detection of ultra-trace amounts of boron

A specialized optical chemical sensor for boron detection was designed using a polymer inclusion membrane (PIM). This unique sensor relies on an encapsulation method to create its optical membrane. The components involved in this sensor include azomethine H (AMH) as the reactive agent, polyvinyl chloride as the foundational polymer, and dinonylnaphthalene sulphonic acid (DNNS) as the extraction agent within the PIM structure. Various parameters, such as membrane thickness, concentration of AMH and DNNS, plasticizer proportions, stirring dynamics, and the pH of the solution under study, significantly affected the sensor’s performance. Within a detection range spanning 4.0–116 ng mL⁻¹ of boron, the sensor demonstrated a strong linear relationship with detection and quantification thresholds of 1.25 and 3.94 ng mL⁻¹, respectively. The peak absorption wavelength (λ_max) for this PIM-based sensor was identified at 424 nm. Moreover, the sensor displayed a reproducibility (RSD) of 1.65% and a repeatability RSD of 1.43%, coupled with a swift response time of approximately 3.0 min. The membrane selectivity was tested against boron in acidic environments. This proposed sensor effectively detected boron in diverse samples such as water, vegetation, soil, and ceramic samples, with findings corroborated by an AAS technique.

Graphical abstract

Schematic representation for the preparation, and complexation of the formed sensor and B‏‏–AMH–DNNS complex