Highly sensitive surface-enhanced Raman scattering detection of brodifacoum and 1080 rodenticide in milk

Megha Mehta; Mark R. Waterland

doi:10.1117/12.2323852

5 September 2018 Highly sensitive surface-enhanced Raman scattering detection of brodifacoum and 1080 rodenticide in milk

Megha Mehta, Mark R. Waterland

Author Affiliations +

Proceedings Volume 10726, Nanoimaging and Nanospectroscopy VI; 1072618 (2018) https://doi.org/10.1117/12.2323852
Event: SPIE Nanoscience + Engineering, 2018, San Diego, California, United States

Abstract

Surface enhanced Raman scattering (SERS) is a powerful technique for food inspection because of its readiness, sensitivity, and minimum sample preparation requirements.¹ Milk is a vulnerable target for contamination. In this work, we demonstrate a reliable SERS method for detecting toxins in milk focusing on brodifacoum, an anticoagulant rodenticide and sodium fluoroacetate, also commonly known as 1080. Surface-enhanced Raman spectroscopy is an advanced Raman technique for ultrasensitive detection of chemical and biological species. Liquid milk presents further challenges due to the complex colloidal nature of milk itself; producing much weaker SERS. Therefore, we applied and omniphobic surface platform, which has the potential to deliver near 100% analyte concentration by constant contact angle drying (and therefore no contact line pinning). Such omniphobic SERS substrates, so-called Slippery liquid-infused porous surfaces (SLIPS) were recently reported.² SLIPSERS method coupled with the dilution of rodenticide spiked milk samples and then extraction with a mixed solvent of methanol: water (3:1) was performed for rodenticide detection.³ All the spectra were taken on an in-house Raman set up based on a Princeton Instruments FERGIE spectrometer using 532 nm excitation wavelength (with 2-3 mW laser power) focused onto the sample using a 40 × 0.65 NA objective. A series of diluted concentrations of each rodenticide ranging from 8- fold dilution to 1600-fold dilution were used to construct a calibration curve. There is a good linear relationship (R² =0.9897) in this concentration range. A critical challenge in detecting bioanalytes is to achieve high specificity, high throughput, and trace-level detection.4 The approach adopted in this work can be extended to detect various molecules in complex chemical and biological matrices.

Citation Download Citation

Megha Mehta and Mark R. Waterland "Highly sensitive surface-enhanced Raman scattering detection of brodifacoum and 1080 rodenticide in milk", Proc. SPIE 10726, Nanoimaging and Nanospectroscopy VI, 1072618 (5 September 2018); https://doi.org/10.1117/12.2323852

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