What Degree of Dilution is Needed to Reduce Matrix Effects in Sers: An Example of the Cu(Oh)2-Ag/Cn-Cdots Substrate for the Detection of Malachite Green?

Abstract

In surface-enhanced Raman spectroscopy (SERS) analysis, the complex matrix composition of the sample matrices would interfere with the quantitative analysis of the target components. This study took the SERS detection of malachite green (MG) as an example to investigate the effect of dilution method on the reduction of matrix effects (MEs) in different matrices (aquaculture water, fish feed and fish meat). Initially, a highly sensitive Cu(OH)2-Ag/CN-CDots substrate was fabricated. This substrate was then used to detect and measure the concentration of MG in sample extracts at various dilutions to calculate the reduction of MEs. The results showed that MEs gradually increased with the increasing matrix complexity, but weakened with increasing dilution factor (DF), ultimately becoming negligible. A linear correlation was observed between the MEs and the logarithm of the DF. Using the logarithmic equation, the minimum DF to ignore MEs was obtained. Specifically, for the detection of MG in fish feed, MEs could be ignored when the DF exceeded 249. For fish meat, MEs were negligible when the DF surpassed 374. Therefore, MEs in SERS detection can be effectively reduced and controlled by the dilution of the sample extracts. This approach represents a simple, effective, and common strategy to reduce MEs in SERS analysis.

Keywords: SERS, matrix effects, dilution, malachite green