Attapulgite modified with covalent organic frameworks as the sorbent in dispersive solid phase extraction for the determination of pyrethroids in environmental water samples

Covalent Organic Frameworks in Sample Preparation

“…In this sense, despite other nanomaterials such as carbon nanotubes (CNTs) and MOFs being highly used as sorbents, in recent years the applicability of COFs has also been evaluated, although in a reduced number of works, as is shown in Table 2 . As it can be seen in the table, COFs have been applied to the extractions of compounds various in nature, such as non-steroidal anti-inflammatory drugs (NSAIDs) [ 54 , 55 ], nitroaromatic compounds (NACs) [ 56 ], fluorochemicals [ 57 ], ultraviolet (UV) filters [ 58 ], pyrethroids [ 59 ] and N-nitrosamines [ 60 ] by the direct dispersion of the COF into the sample matrix after filtration. In most cases, the studied matrix has been water (different origins and types), except in one case, in which a migration study from food packaging materials was carried out [ 58 ].…”

“…Following this principle, the selection of the building blocks used for the syntheses of COFs plays a very important role, so the number of building block combinations almost matches the family of analytes studied. In this format, COFs composed of 1,3,5-triformylbenzene (TFB)/BD [ 54 , 55 ], 2,3,5,6-tetrafluoroterephthalaldehyde (TFA)/TAPB [ 56 ], TFB/ p -phenylenediamine (Pa) [ 57 ], Tp/Pa [ 58 , 59 ] and TFB/4,4′-diamino-p-terphenyl (DATP) [ 60 ] were used as synthesized [ 56 , 57 ], functionalized [ 58 , 60 ] or in combination with another material, such as silica or attapulgite [ 54 , 55 , 59 ]. Among the different COFs and combinations, it is worthy to mention the work of Zhang and co-workers [ 60 ], in which the extraction performances of three nano-titania functionalized COFs taken at different solvothermal reaction stages were evaluated.…”

“…Regarding dSPE procedures, sorbents have been directly dispersed into the samples using different mechanisms, including sonication [ 55 , 56 ], orbital shaking [ 56 ], vibration [ 57 ], manual shaking [ 58 ] and vortexing [ 59 , 60 ], but in all cases, the sorbent was separated by centrifugation prior to analyte desorption with a suitable organic solvent, which varied depending on the nature of the target analyte. They included individual solvents, such as ACN [ 56 , 58 , 59 ] or MeOH [ 60 ], combinations of both of them [ 57 ] or organic solvents containing bases [ 55 ]. From a procedural point of view, it is worth mentioning the work of Li and co-workers [ 54 ], in which the authors synthesized COF-functionalized poly (styrene-divinyl benzene-glycidylmethacrylate) (PS-GMA) particles by dispersing the PS-GMA particles in the hydrothermal reaction media for the synthesis of the COF.…”

“…After dSPE, analytes have generally been separated by UHPLC [ 54 , 60 ] or HPLC [ 55 , 56 , 58 , 59 ] prior to their detection using UV [ 54 , 55 , 58 ], DAD [ 56 , 59 ] or mass spectrometry (MS) [ 60 ] detectors. The good extraction capacity shown by COFs in combination with these techniques allowed obtaining LODs in the order of low µg/L or even ng/L or ng/kg in most cases.…”

Cathodic stripping voltammetric determination of β-cyfluthrin, a pyrethroid insecticide, using polished silver solid amalgam electrode

“…1 insert, have been analysed employing different analytical procedures in various samples types during the last two decades [7]. The use of fluorescence spectroscopy [8,9]; liquid chromatography with mass spectrometry [10,11], diode array [12,13] or ultraviolet [14] detection systems; and also gas chromatography with mass spectrometry detection [9,11,15] have recently reported.…”