# Protocol for preparing cellulose-based aerogels in a deep eutectic solvent as surface-enhanced Raman scattering substrates

## TL;DR

This paper presents a protocol for making SERS substrates using cellulose and gold nanoparticles in a deep eutectic solvent to detect very low concentrations of aqueous analytes.

## Contribution

A new protocol for synthesizing SERS substrates using nonaqueous media and eutectic solvents is introduced.

## Key findings

- The protocol enables detection of aqueous analytes at ultralow concentrations.
- Plasmonic aerogels are synthesized using L-ascorbic acid and eutectic solvents.
- Detailed procedures for substrate fabrication and sample preparation are outlined.

## Abstract

There is an increasing need to detect and identify analytes of diverse origins in low molar concentrations and from complex matrices. Here, we introduce a protocol for preparing surface-enhanced Raman scattering (SERS) substrates that enable the detection of aqueous analytes in ultralow concentrations. We describe the procedure for synthesizing plasmonic aerogels using L-ascorbic acid as a reductor and eutectic solvents as reaction media. We then detail procedures for measurements using these substrates.

For complete details on the use and execution of this protocol, please refer to Panikar et al.1

•Steps to synthesize SERS substrates based on gold nanoparticles and cellulose•Outlines a methodology for the synthesis in nonaqueous media•Procedures for substrate fabrication and sample preparation

Steps to synthesize SERS substrates based on gold nanoparticles and cellulose

Outlines a methodology for the synthesis in nonaqueous media

Procedures for substrate fabrication and sample preparation

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

There is an increasing need to detect and identify analytes of diverse origins in low molar concentrations and from complex matrices. Here, we introduce a protocol for preparing surface-enhanced Raman scattering (SERS) substrates that enable the detection of aqueous analytes in ultralow concentrations. We describe the procedure for synthesizing plasmonic aerogels using L-ascorbic acid as a reductor and eutectic solvents as reaction media. We then detail procedures for measurements using these substrates.