Determination of carbaryl pesticide in Fuji apples using surface-enhanced Raman spectroscopy coupled with multivariate analysis

•Trace pesticide carbaryl in apples was analyzed with SERS and chemometrics.•Carbaryl in apples could be detected at levels as low as 0.5 μg/g.•The method was sensitive enough for identifying apple with carbaryl above MRL.•Carbaryl levels could be predicted by chemometric models with high RPD value.•A novel approach with great potential for analyzing trace contaminants was provided.

Residual pesticides in fruits and vegetables are one of the major food safety concerns around the world. Surface-enhanced Raman spectroscopy (SERS) coupled with chemometric methods was applied for quantitative analysis of trace levels of carbaryl pesticide in apple. The lowest detectable level for carbaryl in apple was 0.5 μg g−1, which was sensitive enough for identifying apple contaminated with carbaryl above the maximum residue level. Quantification of carbaryl residues (0-10 μg g−1) was conducted using partial least squares regression (PLSR) and support vector regression (SVR) models. Based upon the results of leave-one-out cross-validation, carbaryl levels in apples could be predicted by PLSR (R2 = 0.983) or SVR (R2 = 0.986) with a low root mean square errors (RMSE = 0.48 μg g−1 or 0.44 μg g−1) and a high ratio of performance to deviation (RPD = 7.71 or 8.11) value. This study indicates that SERS has the potential to quantify carbaryl pesticide in complex food matrices reliably.