Localized surface plasmon resonance-based optical fiber arsenic ion sensor employing Al₂O₃/GO nanocomposite

A novel optical fiber arsenic (<i>A</i> <i>s</i> ³⁺) sensor, to the best of our knowledge, based on a localized surface plasmon resonance (LSPR) technique, is reported in this paper. The sensor employs <i>A</i> <i>l</i> ₂ <i>O</i> ₃/<i>G</i> <i>O</i> nanocomposite as the sensing film. An experimental investigation demonstrates that the proposed sensor is characterized with a linear response in the range of 0-20 parts per billion (ppb) <i>A</i> <i>s</i> ³⁺ concentration, high sensitivity of 0.217 nm/ppb, and remarkably low limit of detection (LOD) of 0.09 ppb, which is significantly lower than the limit set by WHO in drinking water (10 ppb). Additionally, the sensor exhibits a very fast response time of 0.5 s and exhibits high selectivity towards <i>A</i> <i>s</i> ³⁺ ions over the other heavy metal ions. Furthermore, the sensor displays a very high degree of repeatability, stability, reversibility, and reliability. To validate the proposed sensor's real-world applicability, the sensor is employed to detect arsenic in real water samples. The obtained results exhibit strong alignment with the standard inductively coupled plasma mass spectrometry (ICPMS) method, confirming its accuracy for real-world arsenic detection.