Utilization of magnetic pomelo peel-derived biochar for extraction and liquid chromatography-mass spectrometry determination of opioid drugs in wastewaters.

In this study, magnetic pomelo peel-derived biochar composite was fabricated and applied as a low-cost adsorbent for the simultaneous extraction of morphine-like opioids named morphine, codeine, and 6-monoacetylmorphine from wastewaters, prior to their determination via liquid chromatography-mass spectrometry. A total of four biochar products were synthesized under different pyrolytic temperatures of 400, 500, 600, and 700°C, respectively, and the 400°C biochar was found to have the greatest extraction ability, with enrichment factors of 34, 58, and 61 for the three drugs. The primary adsorption mechanism includes π-π interaction and H-bonding. Parameters affecting the extraction of opioids were optimized. Under optimum conditions (such as pH = 7; adsorbent amount = 15 mg; sample volume = 20 ml; eluent solvent, 200 µl of methanol), the method was proved to be linear in the range of 0.05-10.0 µg/L, with coefficients of determination greater than 0.99, and the limits of detection were 0.006-0.010 µg/L. In-batch and inter-batch precisions were 1.8%-6.5% and 4.8%-10.6%, respectively. The method was successfully applied to the determination of the target opioids in the samples of influent and effluent wastewater. The developed method by using magnetic pomelo peel-derived biochar could potentially be applied for the effective estimation of illicit drug consumption.

Preparation of bamboo-derived magnetic biochar for solid-phase microextraction of fentanyls from urine.

In this study, a biochar-based magnetic solid-phase microextraction method, coupled with liquid chromatography-mass spectrometry, was developed for analyzing fentanyl analogs from urine sample. Magnetic biochar was fabricated through a one-step pyrolysis carbonization and magnetization process, followed by an alkali treatment. In order to achieve desired extraction efficiency, feed stocks (wood and bamboo) and different pyrolysis temperatures (300-700°C) were optimized. The magnetic bamboo biochar pyrolyzed at 400°C was found to have the greatest potential for extraction of fentanyls, with enrichment factors ranging from 58.9 to 93.7, presumably due to H-bonding and π-π interactions between biochar and fentanyls. Various extraction parameters, such as type and volume of desorption solvent, pH, and extraction time, were optimized, respectively, to achieve the highest extraction efficiency for the target fentanyls. Under optimized conditions, the developed method was found to have detection limits of 3.0-9.4 ng/L, a linear range of 0.05-10 µg/L, good precisions (1.9-9.4% for intrabatch, 2.9-9.9% for interbatch), and satisfactory recoveries (82.0-111.3%). The developed method by using magnetic bamboo biochar as adsorbent exhibited to be an efficient and promising pretreatment procedure and could potentially be applied for drug analysis in biological samples.

Use of corn straw-derived biochar for magnetic solid-phase microextraction of organophosphorus pesticides from environmental samples.

In this study, the potentials of utilizing corn straw-derived biochar in environmental sample pretreatment were examined. An one-step magnetization and carbonization process was developed to prepare magnetic biochar by mixing corn straw powder with Fe2+/Fe3+ and then pyrolyzed at different temperatures (400-800 °C). The obtained magnetic biochars were characterized by using scanning electron microscopy, Brunauer-Emmett-Teller isotherms, X-ray diffraction and Fourier transform infrared spectroscopy. Various extraction affecting parameters, such as Fe2+/Fe3+content, pyrolytic temperature, species of desorption solvent, extraction and desorption time, respectively, were studied and optimized. Results showed that the magnetic biochar pyrolyzed at 700 °C exhibited the best extraction performance, with enrichment factors ranging from 52 to 210, presumably due to H-bonding and π-π interactions between biochar and organophosphorus, as well as to the high surface area and pore volume of biochar. The magnetic biochar-based extraction was further combined with gas chromatography-mass spectrometry (GC/MS) to analyze trace organophosphorus pesticides from environmental samples. The method demonstrated good linearity (0.1-50 µg·L-1), low limits of detection (0.02-0.11 µg·L-1), and high recoveries (72.4-96.8%) from spiked water and soil samples. The results of this study suggested the promising potentials of utilizing corn straw-derived biochar for efficiently enriching trace organophosphorus pesticides from complex environmental samples.

Defective Zr-based metal-organic frameworks as sorbent for the determination of fungicides in environmental water samples by rapid dispersive micro-solid-phase extraction coupled to liquid chromatography/mass spectrometry.

In this work, defective Zr-based metal-organic framework was successfully synthesized and evaluated as a dispersive micro-solid-phase extraction sorbent for efficient preconcentration and determination of fungicides in complex water samples. The defective Zr-based metal-organic framework crystal with increased adsorption capacity was successfully synthesized by employing formic acid as the modulator. The extraction conditions, including the pH, extraction time, desorption solvent and desorption time, were comprehensively investigated. Under optimum conditions, it was found that dispersive micro-solid-phase extraction method, coupled with liquid chromatography/mass spectrometry, exhibited a good linear relationship with correlation coefficients greater than 0.9980. The relative standard deviations of inter-day and intra-day precisions ranged from 2.6 to 9.2% and the limits of detection ranged from 0.004 to 0.036 µg/L. These merits, combined with their satisfactory recoveries (>80%), suggested the great potential of defective Zr-based metal-organic framework as a new adsorbent for efficient extraction of trace fungicides. This method exhibits good application potential for the pretreatment of fungicides from environmental water samples.