Non‐Invasive Salivary Electrochemical Quantification of Paraquat Poisoning Using Boron Doped Diamond Electrode

Abstract

The present work describes the first electrochemical method for quantifying paraquat herbicide poisoning in human saliva samples. Paraquat shows two couples of well‐defined peaks in aqueous solution using a boron doped diamond (BDD) electrode. By using square wave voltammetry (SWV) technique under optimum experimental conditions, a linear analytical curve was obtained for paraquat concentrations ranging from 0.800 to 167 µmol L−1, with a detection limit of 70 nmol L−1. This method was applied to quantify paraquat spikes in human saliva samples and in two different water samples (tap and river). The recovery values obtained ranged from 83.0 to 104 % and 99.1 to 105 %, respectively, which highlight the accuracy of the proposed method.

Mesoporous Silica Thin Films for Improved Electrochemical Detection of Paraquat

“…In contrast, electrochemical techniques and instruments are easier to handle, less expensive, and robust for sensing applications. Several reports are available for the electrochemical detection of paraquat, based on bare electrodes (hanging mercury drop electrode, boron doped diamond electrodes, , or gold ultramicroelectrodes , ), on copper electrodes with electrodeposited Bi film, , or on electrodes modified with metal nanoparticles, − carbon nanomaterials (nanotubes or graphene), − organic and polymeric compounds, − and inorganic materials. ,, These methods can have the advantage of applicability to real samples, and also, in most studies the detection limits are below the internationally permissible limits of paraquat in drinking water (Table SI-1). On the other hand, some of the methods reported lean on complex electrode modification, for which there is a lack of understanding of the sensing mechanism.…”

“…Experimental protocol for the electrode preparation and characterization: APTES is electrografted onto a carbon electrode (1); the modified carbon substrate is then immersed into the sol (2) and mesoporous silica thin film is formed by electrochemically assisted self-assembly (3); cross-linking of the silica matrix is ensured by heat treatment and the template is extracted (4); the quality of the silica thin film (4′) and the efficiency of the extraction is checked electrochemically (5); orientation and order of the mesoporous silica was verified by transmission electron microscopy (6). 33 boron doped diamond electrodes, 34,35 or gold ultramicroelectrodes 36,37 ), on copper electrodes with electrodeposited Bi film, 38,39 or on electrodes modified with metal nanoparticles, 40−43 carbon nanomaterials (nanotubes or graphene), 44−46 organic and polymeric compounds, 47−51 and inorganic materials. 41,52,53 These methods can have the advantage of applicability to real samples, and also, in most studies the detection limits are below the internationally permissible limits of paraquat in drinking water (Table SI-1).…”

Analytical Applications of Electrochemically Pretreated Boron‐Doped Diamond Electrodes

“…Interestingly, in the last decade or so, there were many reports of different analytical applications based on CPT‐BDDEs, but lacking comparisons with the performance of the APT or as‐grown electrode; the CPT may have been preceded or not by an APT. This direct, trustful use of CPT‐BDDEs is most probably based on the understanding that HT‐BDD surfaces are hydrophobic and thus might better interact with the investigated analyte, consequently resulting in a higher intensity of the current signal …”