Simple colorimetric screening of paraquat residue in vegetables evaluated by localized surface plasmon resonance of gold nanoparticles

Abstract

The contamination of paraquat in vegetables is widely connected with human health risks, leading to the research interest in developing a paraquat sensing system. This work reports a simple detection method of paraquat based on the electrostatic interaction of paraquat and the negatively charged gold nanoparticles (AuNPs), resulting in the changes of colors from red to blue and the shifting of localized surface plasmon resonance (LSPR) peaks of AuNPs. The limit of detection concentration (C LOD ) of this system was 100 μM paraquat. Moreover, among eight cationic salts tested, NaCl was selective to enhance the detection sensitivity of the system, resulting in the reduction of C LOD to 0.10 μM. This system selectively detected paraquat, but not other tested herbicides (ametryn, atrazine, glyphosate, and 2,4-D-dimethyl ammonium). The paraquat-spiking experiment in kale demonstrated the significant recovery rate of paraquat at 96.0-103.0%, and the relative standard deviations were less than 4%. The developed system was efficient for screening contaminated paraquat in vegetables under unwashed and washed conditions. Three out of five unwashed vegetables had a significant level of paraquat as determined by LSPR values. These results suggested the potential application of this system for a simple screening of contaminated paraquat in vegetables.• Simple paraquat-screening system was developed based on the negatively charged gold nanoparticles.• The limit of paraquat detection of this system was 0.10 μM.• This system was potentially used for a simple screening of contaminated paraquat in vegetables.

Development of sensitive colorimetric aptasensor based on short DNA aptamer and its application to screening for paraquat residues in agricultural soil

“…Although this method showed high sensitivity and selectivity for paraquat detection, it required complex pretreatment steps and complicated data analysis. Later, several simple biosensors for paraquat detection were reported, and their principles were based on the interaction between the positively charged paraquat and negatively charged AuNPs such as 3‐mercapto‐1‐propanesulfonate (3MPS)‐capped AuNPs and citrate‐capped AuNPs 25,26 . For 3MPS, the SO 3 − groups of 3MPS provide the negatively charged surface of AuNPs, which can interact with the positive charges of nitrogen atoms at pyridine rings of paraquat.…”

“…Later, several simple biosensors for paraquat detection were reported, and their principles were based on the interaction between the positively charged paraquat and negatively charged AuNPs such as 3mercapto-1-propanesulfonate (3MPS)-capped AuNPs and citrate-capped AuNPs. 25,26 For 3MPS, the SO 3 − groups of 3MPS provide the negatively charged surface of AuNPs, which can interact with the positive charges of nitrogen atoms at pyridine rings of paraquat. Via this electrostatic interaction, paraquat can induce the aggregation of 3MPS-capped AuNPs, resulting in the color changes from red to blue.…”

A Sensitive Colorimetric Determination of Metformin Based on Gold Nanoparticles Aggregation in Salt Solution

“…found that AuNPs aggregate and precipitate in saline solutions below the NaCl concentration of many bodily fluids and blood plasma. Siri et al [10c] . built AuNPs method for detecting paraquat, NaCl was selective to enhance the detection sensitivity of the system.…”

A Label-Free Electrochemical Aptasensor Based on Zn/Fe Bimetallic MOF Derived Nanoporous Carbon for Ultra-Sensitive and Selective Determination of Paraquat in Vegetables

“…However, due to its chemical stability and solubility in water, PQ can easily accumulate in the environment and in agricultural products, and then enter the human body via food chain. PQ contamination in agricultural products is one of the highly concerning food safety issues in many countries [ 9 ]. It has been reported that PQ was detected in various food products including cabbage, guava, eggplant and round gourd [ 10 , 11 ].…”