Oxidized Buckypaper for Stir-Disc Solid Phase Extraction: Evaluation of Several Classes of Environmental Pollutants Recovered from Surface Water Samples

Abstract

This paper describes, for the first time, the use of oxidized buckypaper (BP) as a sorbent membrane of a stir-disc solid phase extraction module. The original device, consisting of a BP disc ( d = 34 mm) enveloped in a polypropylene mesh pouch, was designed to extract organic micropollutants (OMPs) from environmental water samples in dynamic mode. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze the extracts. Several classes of pesticides and pharmaceuticals were chosen as model compounds to evaluate key parameters affecting the recovery rates. To this end, the effects of adsorption time, desorption time, stirring speed, type and volume of solvent, and sample volume were thoroughly examined. After optimization, a novel and in-depth study was conducted to find a correlation between physicochemical properties of the analytes and extraction yields. Recoveries were mainly governed by a combination of log P and p K values. As indicated, hydrophilic compounds with log P < 1 showed poor affinity for the oxidized BP, compounds having log P > 1 exhibited recoveries ranging between 50% and 100% depending on their p K, while compounds with p K between 6 and 7.5 gave low yields irrespective of their log P. The analytical method was also validated and tested as large scale screening method of OMPs in surface waters. The analysis of real samples revealed the presence of some nonsteroidal anti-inflammatory drugs, sulfonamides, and pesticides at low ng L concentration levels with relative standard deviations lower than 8%.

Chitosan–Graphene Oxide Composite Membranes for Solid-Phase Extraction of Pesticides

“…A specific device, a rotating-disk SPE developed by Tomai et al [47], containing about 40 mg of membrane, was immersed in the pesticide solution (50 mL, 5 µg/L). The system was left under magnetic stirring overnight for 16 h at 100 rpm to favor analyte adsorption on the membrane.…”

Sample Preparation to Determine Pharmaceutical and Personal Care Products in an All-Water Matrix: Solid Phase Extraction

“…Other approaches are based on testing new phases consisted of nanomaterials as more efficient sorbents. Tomai et al [93] performed an SPE with oxidized buckypaper (BP) for Stir-Disc. The aim was to propose an SPE extraction device which combined the properties of carbon nanotubes and magnetic stirring with the main advantages of disk SPE.…”

Chiral Nano-Liquid Chromatography and Dispersive Liquid-Liquid Microextraction Applied to the Analysis of Antifungal Drugs in Milk

“…Terconazole and ketoconazole were not recovered at all. In a previous study [ 33 ], it was verified that compounds with logP greater than 1.5 have a good affinity for BP depending on their pKa values. All analytes selected in this study had logP values in the range between 4.19 and 5.96, which does not justify the dramatic difference in the recovery values.…”

“…Briefly, each SPE device was realized using a 25 mm diameter disc taken from a commercial BP sheet (Nanolab Inc. Waltham, MA, USA). BP is a nanostructured porous material, composed of multi-walled carbon nanotubes (MWCNTs) [ 33 , 34 ]. The BP disc was housed in a circle-shaped polypropylene mesh envelopment sealed at the circumference and with an open pouch to insert the disc.…”