Resorcinol–formaldehyde xerogel as a micro‐solid‐phase extraction sorbent for the determination of herbicides in aquatic environmental samples

Abstract

In this study, organic aerogels were synthesized by the sol-gel polycondensation of mixed cresol with formaldehyde in a slightly basic aqueous solution. Carbon aerogels and xerogels are generated by pyrolysis of organic aerogels. The novel sol-gel-based micro-solid-phase extraction sorbent, resorcinol-formaldehyde xerogel, was employed for preconcentration of some selected herbicides. Three herbicides of the aryloxyphenoxypropionate group, clodinafop-propargyl, haloxyfop-etotyl, and fenoxaprop-P-ethyl, were extracted from aqueous samples by micro-solid-phase extraction and subsequently determined by gas chromatography with mass spectrometry. The effect of different parameters influencing the extraction efficiency of these herbicides including sample flow rate, sample volume, and extraction time were investigated and optimized. Under optimum conditions, linear calibration curves in the range of 0.10-500 ng/L with R(2) > 0.99 were obtained. The relative standard deviation at 50 μg/L concentration level was lower than 10% (n = 5) and detection limits were between 0.05 and 0.20 μg/L. The proposed method was successfully applied to the sampling and extraction of herbicides from Zayanderood and paddy water samples.

Carbon xerogels combined with nanotubes as solid-phase extraction sorbent to determine metaflumizone and seven other surface and drinking water micropollutants

“…Furthermore, these materials are characterized by having high porosity and surface area, controllable pore size, and also having the possibility of being shaped as desired 22 , 23 . These attributes make CXs attractive materials for several applications, including fuel cells 24 , 25 , catalysis 26 – 28 and adsorption for both water treatment 29 , 30 or analytical chemistry 31 , 32 . Regarding water treatment by adsorption, some authors have been studying CXs for removal of specific PSs and CECs: (i) Moral-Rodriguez et al 33 studied different CXs for the adsorption of diclofenac; (ii) Álvarez et al 34 applied CXs as adsorbents for the removal of caffeine and diclofenac; and (iii) Carabineiro et al 35 studied the adsorption capacity of CXs for the antibiotic ciprofloxacin.…”

“…Regarding water treatment by adsorption, some authors have been studying CXs for removal of specific PSs and CECs: (i) Moral-Rodriguez et al 33 studied different CXs for the adsorption of diclofenac; (ii) Álvarez et al 34 applied CXs as adsorbents for the removal of caffeine and diclofenac; and (iii) Carabineiro et al 35 studied the adsorption capacity of CXs for the antibiotic ciprofloxacin. In the field of analytical chemistry, only two studies were found in the literature for the analysis of pollutants by using CXs in SPE: (i) one to determine the effectiveness of an oxidized CX material as sorbent in SPE to preconcentrate lead from tap water samples 32 ; and (ii) another to extract aryloxyphenoxypropionate herbicides from aquatic environmental samples by micro-SPE 31 . However, studies focused on the application of CXs as SPE adsorbent for extraction of other PSs 2 or CECs listed in the Watch List of the EU Decisions 3 – 5 were not found.…”

Resorcinol–formaldehyde aerogel coating for in‐tube solid‐phase microextraction of estrogens

“…Based on the unique advantages, different kind of aerogels have been developed and applied to many fields . Silica aerogels , graphene aerogels , and carbon aerogels were developed for SPME or SPE. Our group prepared an organic hybrid silica aerogel and an ionic liquid‐functionalized silica aerogel as the coatings for fiber SPME, and also produced melamine–formaldehyde aerogel , ionic liquid modified melamine–formaldehyde aerogel , and organic–inorganic hybrid silica aerogel for in‐tube SPME sorbents.…”

Haloxyfop determination by gas chromatography/tandem mass spectrometry in eggs

“…Unlike ELISA, the latter two methods utilize instruments that are not commonplace across feed/food safety or toxicology laboratories. For laboratories that lack LC/MS instruments, a commonly utilized method for haloxyfop detection is gas chromatography/mass spectrometry (GC/MS) which has been applied to fruits, vegetables, aquatic environmental samples and in basic chemical research studies conducted since the 1980s 17–19 . While GC/MS with capillary chromatography has excellent capabilities for chromatographic separability and sensitivity along with numerous mass spectral libraries for unknowns matching, it suffers from problems in specificity in complex matrices with their high potential for overlapping compounds.…”