Fabrication and characterization of a fiber optic surface plasmon resonance (SPR) based phosphate ion sensor utilizing the coating of cobalt oxide (CoO) over the gold coated unclad core of the fiber have been carried out. The interaction between CoO layer and incoming phosphate ion changes the effective refractive index of the CoO layer which affects the resonance wavelength in the SPR spectrum. The performance of the sensor has been evaluated in acidic solution (pH 4) of inorganic phosphate salt (KH₂PO₄). The sensor probe has been found to be irreversible implying one time use of the probe or disposable probe. However, the probe works for 0–100 ppm (0–1.03 mM) concentration range of the phosphate ion (H₂PO₄^-). The sensor possesses maximum sensitivity of 0.3155 nm/ppm with 4.96 ppm as the limit of detection. The sensor is highly selective, fast in response and is suitable to determine the phosphate ion concentration in soil. Since the probe has been fabricated on optical fiber it has the advantages of simplicity, miniaturization and low cost.

已经进行了基于光纤表面等离子体共振 (SPR) 的磷酸盐离子传感器的制造和表征，该传感器利用在光纤的镀金裸芯上涂覆氧化钴 (CoO)。CoO 层和进入的磷酸根离子之间的相互作用改变了 CoO 层的有效折射率，这会影响 SPR 光谱中的共振波长。传感器的性能已在无机磷酸盐 (KH ₂ PO ₄ ) 的酸性溶液 (pH 4) 中进行了评估。已发现传感器探头是不可逆的，这意味着只能使用一次探头或一次性探头。然而，该探针适用于 0–100 ppm (0–1.03 mM) 浓度范围的磷酸根离子 (H ₂ PO ₄ ^-）。该传感器的最大灵敏度为 0.3155 nm/ppm，检测限为 4.96 ppm。该传感器选择性高，响应快，适用于测定土壤中的磷酸根离子浓度。由于探头是在光纤上制作的，因此具有简单、小型化和低成本的优点。