Low-cost and green dispersive solid phase extraction of hydrophilic compounds using titanium dioxide nanoparticles

Review of pretreatment and analytical methods for environmental endocrine disruptors: phthalates

Phthalates, known as phthalate esters (PAEs), are among the most ubiquitous pervasive environmental endocrine disruptors, extensively utilized globally in various facets of modern life due to their irreplaceable role as plasticizers. The exponential production and utilization of plastic goods have substantially escalated plastic waste accumulation. Consequently, PAEs have infiltrated the environment, contaminating food and drinking water reservoirs, posing notable threats to human health. This review provides a comprehensive overview of research advancements in PAE detection and identifies key focal points from 2000 to 2022, utilizing the Web of Science Core Collection. Sample pretreatment and analytical methodologies for PAEs are examined based on bibliometric analysis findings. Pretreatment methods mainly include dispersive solid-phase extraction, magnetic solid-phase extraction, molecularly imprinted solid-phase extraction, and solid-phase microextraction. Laboratory analytical methods such as gas chromatography, liquid chromatography, and immunoassay have been described. Additionally, a discussion on the advantages and challenges of rapid on-site detection methods compared with traditional approaches is presented in alignment with the evolving demands of PAEs detection. Based on the current research progress, future studies can focus on the demand of rapid detection of PAEs.

Self-synthesized TiO2 nanoparticles-pH-mediated dispersive solid phase extraction coupled with high performance liquid chromatography for the determination of quinolones in biological matrices

A simple and efficient pH-mediated dispersive solid phase extraction (dSPE) based on terbium doped titanium dioxide nanoparticles (TiO₂-Tb NPs) combined with high performance liquid chromatography (HPLC) has been firstly developed for the determination of quinolones (QNs) in various biological samples. The adsorption kinetics and isotherms were investigated to indicate that the kinetic and equilibrium adsorption were well-described by pseudo-second order kinetic and Henry, Langmuir isotherm model, respectively. The parameters influencing the extraction performance were systematically investigated. The QNs are transferred into TiO₂-Tb NPs in the first step at pH = 6.0 and eluted into acidic aqueous phase at pH = 2.5 in the second step. Under the optimum extraction and determination conditions, a linearity range with the coefficient of determination (R²) from 0.9977 to 0.9991 were obtained in a range of 10-10,000 ng mL^-1. The limits of detection (LODs) based on a signal-to-noise ratio of 3 were 3.3 ng mL^-1. The recoveries of the three QNs in human urine, rabbit plasma and serum samples ranged from 69.3% to 117.6%, with standard deviations ranging from 2.4% to 9.9%. Therefore, this pH-mediated dSPE-HPLC method exhibited the advantages of remarkable sensitivity, ease of operation, rapidity, low cost and environmental friendliness.

Siderophore purification with titanium dioxide nanoparticle solid phase extraction

Siderophores are metal chelators produced by microorganisms to facilitate binding and uptake of iron. The isolation and characterization of siderophores are impeded by typically low siderophore yields and the complexity of siderophore-containing extracts generated with traditional purification methods. We investigated titanium dioxide nanoparticle solid-phase extraction (TiO2 NP SPE) as a technique to selectively concentrate and purify siderophores from complex matrices for subsequent LC-MS detection and identification. TiO2 NP SPE showed a high binding capacity (15.7 ± 0.2 μmol mg-1 TiO2) for the model siderophore desferrioxamine B (DFOB) and proved robust to pH changes and the presence of EDTA. These are significant advances in comparison to immobilized metal affinity chromatography (IMAC). The TiO2 NP SPE was highly selective and recovered 77.6 ± 6.2% of DFOB spiked to a compositionally complex bacterial culture supernatant. The simple clean-up procedure removed the majority of contaminants and allowed direct detection of siderophores from the LC-MS base peak chromatogram. The 'untargeted' purification and analysis of an untreated supernatant of iron-deprived bacterial culture allowed for the direct identification of two known and three novel ferrioxamines. Thus, TiO2 NP SPE in combination with LC-MS offers great potential as a discovery platform for the purification and subsequent quantification or identification of novel siderophores of microbial origin.