Detection of petrol adulteration at concentration of 5 % at high sensitivity is challenging. The proposed SPR sensor shows high performance in term of sensitivity and optical energy coupling efficiency (OECE) which showed the silver thickness of 37 nm gives the sensitivity of 491.3043°/RIU higher by 1.25, 2.4, and 8.07 times of the sensitivity for the silver thickness is 40, 45 and 50 nm, respectively. For silver thickness 37 nm, the OECE is 99 % higher than silver thickness is 40, 45 50 and 55 nm with OECE of 70.64, 58.52, 48.86 and 35.51 %, respectively. This indicates that the fields were enhanced by 177.61% than when the silver thickness was 55 nm. At kerosene concentrations of 5% and 40% in petrol, the sensitivity, FOM, and DA are 330.43 °/RIU, 63.9380, and 0.1634, and 116.42, 0.2370, and 491.3043 °/RIU, respectively, demonstrating improvements of 18% and 5.61% compared to a recently published research. Mechanical scanning constrained by a motor resolution of 0.001°, utilizes a diverging beam reflected onto a CCD sensor of 3,648 pixels, paired with a 12-bit ADC converter, yielding an exceptional angular resolution of 6.694×10-8°, representing an improvement of 99.98% above mechanical scanning. Its resolution is 7×10-10 RIU.

In SPR sensor multilayer is important process in improving the performance of the sensor chip. However, during the coating process of these multilayers the coated layer is highly susceptible to roughness the effect becomes more when the size of the chip is bigger, coated which leads to surface roughness. Thus, the research focuses on quantifying the impacts of surface roughness of multilayers on the performance of the SPR sensor. The Whittaker filter was proposed to mitigate the roughness effect without changing the hardware part. The study found that – sample interface roughness has the most negative impact on SPR sensor performance. The proposed Whittaker filter showed that can recovers the distorted SPR signal caused by roughness effect at the interface the Whittaker filter recovers about 50 - 60 % of this performance loss. Surface roughness decreases detection accuracy by approximately 25 - 30%, with the filter providing about 40 - 50% recovery. The error caused by rough interfaces were reduced to the average of approximately 49% Thus in area where there is budget constraint in achieving smooth surface during coating then the Whittaker filter provides a viable compromise, recovering significant performance without physical intervention.