Fast Detection of Copper Content in Rice by Laser-Induced Breakdown Spectroscopy with Uni- and Multivariate Analysis

Abstract

Fast detection of heavy metals is very important for ensuring the quality and safety of crops. Laser-induced breakdown spectroscopy (LIBS), coupled with uni- and multivariate analysis, was applied for quantitative analysis of copper in three kinds of rice (Jiangsu rice, regular rice, and Simiao rice). For univariate analysis, three pre-processing methods were applied to reduce fluctuations, including background normalization, the internal standard method, and the standard normal variate (SNV). Linear regression models showed a strong correlation between spectral intensity and Cu content, with an R2 more than 0.97. The limit of detection (LOD) was around 5 ppm, lower than the tolerance limit of copper in foods. For multivariate analysis, partial least squares regression (PLSR) showed its advantage in extracting effective information for prediction, and its sensitivity reached 1.95 ppm, while support vector machine regression (SVMR) performed better in both calibration and prediction sets, where Rc2 and Rp2 reached 0.9979 and 0.9879, respectively. This study showed that LIBS could be considered as a constructive tool for the quantification of copper contamination in rice.

Filler-Modified Castor Oil-Based Polyurethane Foam for the Removal of Aqueous Heavy Metals Detected Using Laser-Induced Breakdown Spectroscopy (LIBS) Technique

“…The selection of the standard line referred to the organic nature of COPUFs, in which the appearance of the CN band line is always consistent. Other potential standard lines, such as Ca I 422.6 nm that have close ionization energy with Pb I (405.7 nm), could not be used since the Ca content in each sample was different due to different modifying fillers added [36]. The same reason also applied to C I (247.8 nm), since COPUF with AC fillers had higher carbon content.…”

Rapid Determination of Cadmium Contamination in Lettuce Using Laser-Induced Breakdown Spectroscopy

“…Atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectroscopy (ICP-OES), and inductively coupled plasma with mass spectrometry (ICP-MS) are common methods to detect concentrations of heavy metal Cd in food [ 9 ]. Though the results are accurate, these traditional methods are expensive and need complex sample preparation with a strongly acidic environment and high temperatures for sample digestion [ 10 ]. This process is time-consuming.…”

Fast Quantification of Honey Adulteration with Laser-Induced Breakdown Spectroscopy and Chemometric Methods

“…A laboratory-assembled LIBS device was used for honey adulteration detection. The detailed description of the device was introduced in our previous published article [16]. First, 8 g of sample was added in 12-well plates and placed in a X-Y-Z moving stage.…”