Tolfenamic acid on-line preconcentration strategy on carbon nanotubes minicolumn with fluorimetric detection

• Published in: Talanta (Oxford) 2020-01, Vol.207, p.120345-120345, Article 120345
• Main Authors: Muñoz, Vanesa, Talio, María Carolina, Gil, Raúl, Fernández, Liliana Patricia
• Format: Article
• Language: English
• Subjects: Bovine serum albumin; Emerging pollutants; Flow injection analysis; Tolfenamic acid traces; Water samples
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2019.120345

Nonsteroidal anti-inflammatory agents (NSAIDs) are a group of pharmaceuticals considered one of the most popular drugs used in clinical practice applied to the treatment of acute and chronic conditions. Some pharmaceuticals products are excreted reaching the environment and altering the balance of ecosystems. This work proposes a new fluorimetric flow injection (FI) methodology for the NSAID tolfenamic acid quantification based on the quenching effect of the analyte on fluorescent signal of bovine serum albumin fluorophore. Results put in evidence a mechanism of static quenching, with a Stern Volmer constant value of 1.8 × 107 L mol−1. To achieve the selective on-line preconcentration of analyte, a carbon nanotubes mini column was introduced in the FI configuration producing a beneficial effect on high sampling frequency, minimum sample and reagents consumption. The experimental factors that influence batch fluorescent signal and FI analysis have been studied and optimized. At optimal experimental conditions, an adequate tolerance to foreign species was shown. With the flow configuration, a LOD of 0.019 μg L−1, a LOQ of 0.058 μg L−1 were obtained with a sampling rate of 30 samples h−1. The new methodology was successfully applied to analyte determination in tap water and pharmaceutical and factory waste samples with recuperation near to 100%. [Display omitted] •A novel tolfenamic acid determination technique is proposed.•Fluorescence coupled with flow injection analysis improves sampling process.•The possible mechanism of quenching is proposed.•This methodology showing good reproducibility with low operation cost.•It was applied to the determination of TOL in water samples from San Luis city (Argentina).