Metal Nano Layer Coating for Improving the Detection and Recognition of Micro-Poisons Using Reflection Spectroscopic Measurement

Abstract

Metal nano layer coating for increasing the sensitivity of spectroscopic measurements is proposed and experimentally demonstrated in this paper. The metal nano layer will attract the micropoisons from any measured aqueous sample increasing the concentration of the micro-poison in the vicinity of the surface and significantly improves the sensitivity of the spectroscopic measurement. The demonstration was carried out using Fourier Transform Infra-Red (FTIR) operating in the MIR 400 cm −1 -4000 cm −1 and 5 nm Gold layer which was grown on silicon oxide substrate. In the experimental demonstration Malathion organophosphate pesticide was used as micro-poison. The spectroscopic measurement proves that Malathion was attracted to the metal nano layer. Furthermore, the absorption lines of Malathion were detected and recognized. This proof of principle can be applied to any Internal Reflection Elements (IRE) and it can be used to purify any aqueous solutions and atmosphere from micro-poisons which will be attracted to the metal Nano layer.

Real-Time Metasurface Sensor for Monitoring Micropoisons in Aqueous Solutions Based on Gold Nanoparticles and Terahertz Spectroscopy

“…Figure 6 shows the effect of gold ATR coatings on the detection of malathion [ 11 ]. There are two important conclusions: The first is that metal nanoparticles attract malathion and probably other micropoisons in aqueous solutions.…”

“…There are two important conclusions: The first is that metal nanoparticles attract malathion and probably other micropoisons in aqueous solutions. The second is that the attraction of the micropoison to the gold nanoparticles increases the sensitivity and recognition by ATR FTIR measurement [ 11 ]. Based on those conclusions, we simulated the influence of adding gold nanoparticles to the DSRR gap on the sensor sensitivity.…”

“…The proposed MS sensor detection mechanism is based on shifting of the MS sensor resonance frequency, f res , due to the presence of micropoisons near the gap of the DSRR of the MS, rather than the MIR spectroscopic signature of the micropoison [ 18 ]. Furthermore, significant improvement in the MS sensor sensitivity can be achieved by adding a thin layer of gold nanoparticles on the front side of the MS sensor, especially in the gap of the DSRR [ 11 ].…”

“…On the other hand, the spectroscopic methods [ 8 , 9 ] are fast and can be done in real time. However, the FTIR-ATR method is less sensitive and requires special coatings for the ATR crystal [ 10 , 11 ].…”

“…The resonance frequency, fres, shift due to the presence of micropoisons is measured using a high-resolution compact terahertz CW frequency-domain spectrometer. Adding a gold nanoparticle coating on the MS surface, especially in the gap of the DSRR, causes the micropoisons such as OPs to adhere to the MS, increasing the detection sensitivity significantly [11]. In this study, we present a full proof of concept of malathion detection using a perfect absorber MS manufactured by well-known and very inexpensive printed circuit board (PCB) technology.…”