Hollow‐fiber liquid‐phase microextraction for the determination of pesticides and metabolites in soils and water samples using HPLC and fluorescence detection

Abstract

A new and simple method has been developed for the determination of a group of four benzimidazole pesticides (carbendazim/benomyl, thiabendazole, and fuberidazole), a carbamate (carbaryl), and an organophosphate (triazophos), together with two of their main metabolites (2-aminobenzimidazole, metabolite of carbendazim/benomyl, and 1-naphthol, metabolite of carbaryl) in soils. First, an ultrasound-assisted extraction (UAE) was performed, followed by evaporation and reconstitution in water. Then, extraction and preconcentration of the analytes was accomplished by two-phase hollow-fiber liquid-phase microextraction (HF-LPME) using 1-octanol as extraction solvent. Parameters that affect the extraction efficiency in HF-LPME technique (organic solvent, pH of the sample, extraction time, stirring speed, temperature, and ionic strength) were deeply investigated. Optimum HF-LPME conditions involved the use of a 2.0 cm polypropylene fiber filled with 1-octanol to extract 10 mL of an aqueous soil extract at pH 9.0 containing 20% (v/v) of NaCl for 30 min at 1440 rpm. Separation and quantification was achieved by HPLC with fluorescence detection (FD). The proposed optimum UAE-HF-LPME-HPLC-FD methodology provided good calibration, precision, and accuracy results for two soils of different physicochemical properties. LODs were in the range 0.001-6.94 ng/g (S/N = 3). With the aim of extending the validation, the HF-LPME method was also applied to different types of waters (Milli-Q, mineral and run-off), obtaining LODs in the range 0.0002-0.57 μg/L.

Recent advances in combining microextraction techniques for sample pre-treatment

“…As listed in Table 5, the analytical recoveries of eight OPPs (three spiked levels) in fish tissues were 73.8-101.8% [51]. Benzimidazole-pesticide recoveries percentages were 85-117% in all forest soil, and 86-115% in lapilli soil [52]. Recoveries from environmental waters were 83-102%, 86.4-102.4%, and 93.5-101.3% for CPs [53], HCHs [54] and DDT [55], respectively.…”

“…:  PHWE [50] for the extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from sewage sludge;  UAE [51,52] for the extraction of OPPs and benzimidazole pesticides from fish tissue and soils; and,  MAE [53][54][55] for the extraction of CPs, hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethane (DDT) and their metabolites in water samples [53][54][55] ( Table 5). …”

“…Although reported procedures when using PHWE and UAE worked in an off-line mode (two-stage extraction procedures [50][51][52]), some attempts have been made to perform one-step MAE-HF-LPME extraction procedures [53][54][55]. The design implies the use of an external cooling system, in which an HF segment mounted on the needle tip of the microsyringe is placed (outside the microwave oven), which is connected to a glass bottle containing the sample and the extractant (placed into the microwave oven).…”

Hollow‐fiber liquid‐phase microextraction combined with capillary HPLC for the selective determination of six sulfonylurea herbicides in environmental waters

“…Hollow‐fiber liquid‐phase microextraction (HF‐LPME) is another easy, cheap, environmentally friendly, and miniaturized alternative for sample preparation, which allows multiple sample processing steps, for example, extraction, cleanup, and analyte enrichment to be performed in a single goal . Several methods and analytical applications for trace‐level extraction of multiclass pesticides from environmental water and soil samples have been proposed using HF‐LPME methodologies . However, since the use of a single step and selective three‐phase HF‐LPME has not been considered to date for the determination of SUHs from environmental water samples, we have proposed a new sample treatment for the selective extraction of six SUHs: triasulfuron (TS), metsulfuron‐methyl (MSM), chlorsulfuron (CS), flazasulfuron (FS), chlorimuron‐ethyl (CSE), and primisulfuron‐methyl (PSM).…”

Temperature-controlled ultrasound- and vortex-assisted liquid-liquid microextraction combined with GC for the determination of the concentrations of organophosphorus pesticides in beverage samples

“…Traditional extraction techniques are laborious and consume a large amount of organic solvent . Recently, liquid‐phase microextraction methods, including single‐drop microextraction (SDME), dispersive liquid–liquid microextraction (DLLME), and hollow‐fiber liquid‐phase microextraction, have been developed for the analysis of pesticide residues in foods and in environmental and biological samples .…”