Quantitative Determination of Auramine O in Bean Curd Sheets by Dispersive Solid Phase Extraction with Dynamic Surfaced-Enhanced Raman Spectroscopy

Abstract

Dynamic surfaced-enhanced Raman spectroscopy (D-SERS) has been widely applied in chemical analysis due to its simple operation and high sensitivity. A new method was developed for the quantitative determination of auramine O in bean curd sheets using D-SERS. Through the optimization of measurement time interval and determination and stability and other SERS conditions, effective and stable SERS measurements of auramine O were performed during the sample solution evaporation process. Dispersive solid phase extraction was applied to remove as many impurities as possible. Following the evaluation of the spectra, the peak at 1114 cm⁻¹ in the SERS spectrum was selected to quantify the auramine O present in the bean curd sheets. A matrix standard curve-external standard method was used to conduct the statistical analysis. The results showed that there was good linearity between the chromatographic SERS peak and the concentration of auramine O across the range from 0.5 to 10 mg/L. The correlation coefficient (R²) was greater than 0.99. At spiked levels of 0.5, 1.0, and 5.0 mg/kg, the average recoveries of auramine O in the bean curd sheets were from 92.3% to 96% and the relative standard deviations were from 4.6% to 8.3%. The lowest spiked concentration was determined to be the limit of quantitation. As a consequence, this study provides a new stable, effective, rapid approach for the quantitative determination of auramine O in bean curd sheets.

Keywords:

• Auramine O
• bean curd sheets
• dynamic surfaced-enhanced Raman spectroscopy
• hot spots

Acknowledgments

We thank Rosalie Tran, PhD, from Liwen Bianji, Edanz Editing China for editing the English of this manuscript.

Disclosure statement

There are no conflicts of interest to declare.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This research was supported by the Major science and technology innovation engineering projects of Shandong Province (No. 2019JZZY011013), the Agricultural Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences (No. CXGC2017A03), the Shandong Independent Innovation and Transformation of Achievements (Grant number 2014ZZCX02703), the Shandong Provincial Key Laboratory of Food Quality and Safety Inspection Technology Open Project, and the Joint Fund Project of the Three Institutions (Grant number ZR2016YL025).