The large surface area, good thermal and solvent stabilities, diverse structures and properties make covalent-organic frameworks (COFs) promising porous materials for gas storage, catalysis, adsorption and separation. Recently, COFs have received considerable attention in the fields of chromatography and sample pretreatment. This review summarizes recent advances in the application of COFs in chromatography and sample pretreatment. The prospects of COFs in chromatography and sample pretreatment are also presented.
Nicotine is an important indicator in the quality evaluation of tobacco and its related products. Moreover, it is essential to monitor nicotine presence in the environment, food, and human organs. Therefore, the development of a suitable and efficient determination method is crucial to precisely detect nicotine in various samples and complicated matrices. This article reviews the methods of sample preparation (molecular imprinting technology and solid phase/liquid phase microextraction) and methods for nicotine analysis, such as spectrophotometry, liquid chromatography, gas chromatography, capillary electrophoresis, and electrochemical methods, reported in recent years. The advancement in the applications and scopes of these methods are discussed. Furthermore, the sensitivity, accuracy, and detection efficiency of these methods are elaborated on the basis of the reported nicotine determination methods.
The aim of this study was to investigate the stereoselective effects of a popular pharmaceutical and personal care product component ibuprofen (IBU) on adult zebrafish using sphingolipidomics. Sphingolipidomics is an effective method developed to determine sphingolipids present in biological samples using ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry. Using this method, 46 sphingolipids in adult zebrafish brain samples were quantified after rac-/R-(-)-/S-(+)-IBU exposure, and the biomarkers were selected using chemometric approaches, including principal component analysis and orthogonal partial least squares discrimination analysis. Besides, combined with the results of the Duncan post hoc test and Dunnett post hoc comparison, sphingolipidomic perturbations were found to be induced after exposure to ibuprofen at environmental concentrations, and enantiomers of ibuprofen had stereoselective effects on zebrafish. This study may provide a new insight on the influence of ibuprofen on aquatic organisms.
A rapid, simple and sensitive ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the determination of ambroxol hydrochloride in human plasma, and bioequivalence of its preparation was evaluated. The 50 μL-plasma sample was treated with methanol for protein precipitation, while ambroxol-d5 was used as an internal standard (IS). The separation was carried out on a Waters XBridge BEH C18 column (50 mm×2.1 mm, 2.5 μm) by gradient elution at a flow rate of 0.4 mL/min, with 0.1% (v/v) formic acid aqueous solution and methanol containing 0.1% (v/v) formic acid as the mobile phases. The analyte was detected using an electrospray ionization source in positive ion multiple reaction monitoring (MRM) mode. The calibration curves were linear in the range of 2-400 ng/mL (r=0.998). The intra- and inter-run accuracies were 97.1%-108.7%, the intra- and inter-run precisions were 1.0%-5.6%. The method was applied to the determination of the plasma concentration of the six healthy subjects after the oral administration of 30 mg of test and reference preparations. The bioavailability was (102.3±14.8)%. The 90% confidence intervals of the test preparation's pharmacokinetic parameters were 80.0%-125.0% of the reference preparation's corresponding parameters. Thus, it is proved that the test preparation and reference preparation are bioequivalent.
A polymeric monolithic solid phase extraction sorbent was fabricated from sole ethylene glycol dimethacrylate in a syringe and applied as a sorbent for the determination of carbamazepine (CBZ) and 10-hydroxy-carbamazepine (MHD) in human serum using high performance liquid chromatography. The effects of reaction temperature and reaction time on the extraction performance of the target compounds were investigated. The parameters, such as washing solvent, and elution solution and its volume, were optimized. Under the optimized condition, the purification and enrichment of CBZ and MHD in human serum were successfully achieved on the proposed poly ethylene glycol dimethacrylate (EDMA) monolithic column. The linear ranges were 0.02-40 μg/mL for CBZ and 0.05-100 μg/mL for MHD. The results indicated that the method exhibited good linearity in the corresponding ranges with the correlation coefficients (r) of 0.999. The limits of detection (S/N=3) of CBZ and MHD were 0.004 μg/mL and 0.01 μg/mL, respectively. The average recoveries at three spiked levels of CBZ and MHD were 92.7% and 94.2%, respectively, with relative standard deviations (RSDs) ≤ 6.1%. Furthermore, the intra column to column (n=3) and inter batch to batch (n=5) RSDs were no more than 5.3%. The RSDs of eight repeated extraction cycles were no more than 5.8%. The developed method is effective and simple, and is suitable for the determination of CBZ and MHD in human serum.
To develop a rapid, effective, and accurate method for the simultaneous determination of chloramphenicol, thiamphenicol, and florfenicol in human blood by pass-through cleanup solid-phase extraction combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), novel nano-titania-coated modified magnetic graphene oxide (TiO2-Mag-GO) is used as the PRiME pass-through cleanup solid-phase extraction sorbent for the cleanup of blood phospholipids. The chromatographic separation was performed on an Eclipse Plus C18 column (100 mm×2.1 mm, 1.8 μm) using 0.08% (v/v) aqueous ammonia solution and acetonitrile having aqueous ammonia (0.08%, v/v) as mobile phases. The tandem mass spectrometer was operated using electrospray ion source (ESI) in the multiple reaction monitoring (MRM) mode. The results showed that the linearities were in the range of 0.1-10.0 μg/L with the determination coefficients (r2) greater than 0.9990 for chloramphenicol, thiamphenicol, and florfenicol. The limits of quantification (LOQs) (S/N>10) in the blood samples were between 0.056 and 0.082 μg/L and the recoveries ranged from 90.0% to 105% at three spiked levels. Precision values expressed as relative standard deviations (RSDs) were in the range of 1.2%-6.6%. The developed method can be used for routine analyses to determine chloramphenicol, thiamphenicol, and florfenicol in clinical studies.
To establish a method for the determination of veterinary drug residues in eggs by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), samples were extracted and purified using frozen lipid filtration combined with the QuEChERS method taking advantage of dispersive solid-phase extraction (DSPE). A total of 125 veterinary drug residues in eggs were analyzed, encompassing 11 classes of drugs (nitroimidazoles, benzimidazoles, sulfonamides, quinolones, macrolides, tetracyclines, androgens, progestational hormones, glucocorticoids, estrogens, and chloramphenicols). The drugs were extracted in acetonitrile/water (70:30, v/v) containing 0.1 mol/L EDTA. The precipitation of lipids and proteins was promoted by performing the extractions at very low temperature (-20℃) for 2 h. Further purification was carried out using dispersive solid-phase extraction (DSPE) followed by dilution of the supernatant. Detection and analysis of veterinary drug residues by UHPLC-MS/MS was conducted and quantified by the external standard method. Our results showed that this method gave good linearity within a certain concentration range (relative coefficient, R2 ≥ 0.99), and the acceptable limits of quantification were determined to be 2.0-60 μg/kg for the 125 veterinary drugs. Good recovery values (60.4%-119.3%) were achieved for all the 125 veterinary drugs with RSD values ranging from 0.3% to 16.1%. This method proved suitable for the rapid determination of veterinary drug residues in eggs with a simple, accurate, and low-cost procedure.
Ultrasound-assisted extraction coupled with liquid chromatography-tandem mass spectrometry (UAE-LC-MS/MS) was used to develop a trace multi-residue detection method for six novel acetolactate synthase (ALS) inhibitor herbicide residues (mesosulfuron-methyl, halosulfuron-methyl, bispyribac-sodium, pyriminobac-methyl, orthosulfamuron, and ethoxysulfuron) in oil crops. In this study, the recoveries of the six herbicides based on ultrasound-assisted and QuEChERS extraction methods were compared, and five adsorbent materials (C18, PSA, GCB, Florisil, and EMR) were optimized based on their purification and adsorption capacities. The results showed that the ultrasound-assisted extractions gave recoveries greater than 90% for the six compounds. Furthermore, EMR showed little adsorption for the six compounds and a reduced matrix effect by effective removal of the oil lipids. The six herbicide residues had good linearities in the concentrations ranging from 0.05 to 500.0 μg/L, and the correlation coefficients were greater than 0.9984. The limits of detection and limits of quantification for this method were 0.08-0.8 μg/kg and 0.25-2.5 μg/kg, respectively. The recoveries of the six pesticides at three spiked levels in four matrices (rapeseed, soybean, peanut, and sunflower seed) ranged from 70.7% to 103.8%, with relative standard deviations of 0.8%-9.2%. This method was successfully applied to the simultaneous determination of six ALS inhibitor herbicide residues in oil crops.
A method for the simultaneous determination of four tocopherols, four tocotrienols, four phytosterols, β-carotene and squalene by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed. After saponification, the samples were extracted with petroleum ether, and the extract solution was concentrated by rotary evaporation. The residue was dried under a N2 atmosphere and dissolved with methanol. The 14 nutrients were separated on a Poroshell 120 PFP column (150 mm×3.0 mm, 2.7 μm) by gradient elution with 0.1% (v/v) formic acid aqueous solution and methanol containing 0.1%(v/v) formic acid as the mobile phases at a flow rate of 0.3 mL/min. The detection was performed using an atmospheric pressure chemical ionization (APCI)-mass spectrometer with selective reaction monitoring (SRM) in positive mode. The results were linear in the range of 0.05-10.0 mg/L for the 14 nutrients, and the correlation coefficients (r) were no less than 0.9971. The average recoveries of the 14 nutrients in the vegetable oil samples ranged from 80.7% to 100.5% at three spiked levels, and the relative standard deviations (RSDs) were less than 6.0%. The limits of detection (LODs) ranged from 0.01 to 0.30 μg/g. The limits of quantification (LOQs) were in the range of 0.04-1.00 μg/g. The proposed method is sensitive, accurate, fast and stable, and is suitable for the simultaneous determination of the 14 nutrients in vegetable oil samples.
An effective method based on ultra-high performance liquid chromatography-triple quadrupole/electrostatic field orbitrap mass spectrometry (UHPLC-Q-Orbitrap MS) was developed for high-throughput screening and quantitative analysis of 112 pharmaceutical and personal care products (PPCPs) in water. The water samples were separately extracted under alkaline and acidic conditions and cleaned on an SPE column (Cleanert PEP-2). The sample was separated and detected by UHPLC-Q-Orbitrap MS, and the data were collected in full MS scan/date dependent MS2 mode. All the 112 PPCPs in water were qualitatively screened and quantified on the basis of the peak area of the precursor ion. The PPCPs showed a good linear response in the mass concentration range of three orders of magnitude (r2 ≥ 0.9901), and the limits of quantification were between 0.002 μg/L and 0.8 μg/L. The recoveries of 60.1%-129.5% were achieved at different spiked levels of 0.2, 0.4, and 0.8 μg/L, and the RSDs were 1.1%-17.8% (n=6). Moreover, the method was used to screen the PPCPs in water samples acquired from seven regions of Dalian city (China), and 16 PPCPs were identified and quantified. Therefore, this simple method with high sensitivity and wide screening range can be applied to water quality management and environmental risk monitoring.
A comprehensive analytical method was developed for simultaneous determination of 28 corticosteroids in surface water based on ultra-high performance liquid chromatography- electrospray tandem mass spectrometry (UHPLC-ESI-MS/MS). The solid-phase extraction was performed using hydrophilic-lipophilic balance (HLB) cartridges, and the chromatographic separation was achieved on a reversed-phase C8 column. Qualitative and quantitative analyses were performed in the dynamic multiple reaction monitoring (DMRM) mode using positive and negative electrospray ionization (ESI±). The 28 target compounds were quantified by the internal standard method. Good linear relationships were obtained (R2>0.99) for the 28 analytes in the concentration range of 1.0-100 μg/L. The method limits of detection and quantification were in the range of 0.21-0.48 ng/L and 0.32-0.72 ng/L, respectively. When the matrix spiking levels were at 5.0, 10, and 50 ng/L, the average recoveries for the target compounds ranged from 68.6% to 108.7%, and the relative standard deviations (RSDs) were between 0.1% and 8.1%. Because of its high sensitivity, good precision, and reliability, this method can be widely applied to trace monitoring of glucocorticoids and mineral ocorticoids for investigating their behaviors and risks of corticosteroids in the environment.
A simple and rapid method was developed for the analysis of ofloxacin enantiomers by chiral ligand exchange-high performance liquid chromatography (CLE-HPLC). In addition, the influences of common cations (Ca2+, Mg2+, Fe3+, Zn2+) and the content of humic acid (HA) on the separation were investigated. The separation was carried out on a C18 column (25 cm×0.46 cm, 5 μm). The mobile phase was 20% (v/v) methanol aqueous solution containing 4 mmol/L L-isoleucine (as ligand) and 3 mmol/L CuSO4. The pH of the mobile phase was 4.5, and the flow rate was 1.0 mL/min. The column temperature was 40℃, and the detection wavelength was 293 nm. The ofloxacin enantiomers (ofloxacin and levofloxacin) were separated within 18 min and the resolution (R) was 2.70. The results showed that metal cations and HA had no significant influence on the resolution of ofloxacin enantiomers. However, the measured peak area of ofloxacin enantiomers decreased particularly in presence of Fe3+ and on increasing HA content. The proposed method can rapidly and efficiently determine ofloxacin and its chiral isomers in surface water, the influences of Fe3+ and HA content should be considered for verifying the applicability of the method.
In this study, the extraction and purification improvements of the QuEChERS method were coupled with gas chromatography-mass spectrometry (GC-MS) to determine 20 pesticides in panax ginseng. Dry ginseng powder was mixed with water, and the solution was then extracted with acetonitrile and purified with N-propylethylenediamine (PSA) and MgSO4 to remove co-extractives that might interfere with the results. The target compounds were detected after electron-impact ionization in selected ion monitoring (SIM) mode. Under optimum conditions, the method gave a good linear relationship for the determination of the pesticides within a certain concentration range, with correlation coefficients greater than 0.990. Moreover, the limits of detection (S/N=3) were 0.002-0.007 mg/kg, the limits of quantification (S/N=10) were 0.002-0.024 mg/kg, and the average recoveries for pesticides in panax ginseng were 70.41%-114.06%, with relative standard deviations of 0.76%-15.47%. In comparison with previous methods, the new procedure has the advantages of simple sample preparation and higher sensitivity.
Based on migration procedures using simulated gastric juice specified in the EU toy Safety Standard EN 71-3:2013/A2:2017, a method was developed for the determination of monomethyltin (MMT) migration from toys by gas chromatography-mass spectrometry (GC-MS). Further, a reliable confirmation method for judgement of a false positive for MMT obtained by GC-MS, was established. After optimizing the migration conditions, derivatization steps and chromatographic parameters, the method yielded a linear range from 0.02 to 1.0 mg/L with a correlation coefficient (R2) of 0.9992. The limits of detection and quantification of the method were 0.11 and 0.32 mg/kg, respectively. The recoveries were 86.2%-104.2% under different spiked levels (0.5, 1.0 and 1.5 μg), and the relative standard deviations were 3.1%-8.2% (n=6). MMT migration ranging from 0.44 to 0.67 mg/kg was detected in the surface coating of tin-plating (Sn-Fe alloy) toy materials, which was subsequently confirmed to be false positive. Therefore, a novel confirmative approach using methanol or acetone as the migration solvent was proposed, aiming at verifying the false positive of MMT. The results showed that the previously positive MMT detected by GC-MS could no longer be detected when treated by these migration solvents.Hence, this approach can be used to confirm false positive detected for MMT after GC-MS detection.
A chromatographic method was developed for the determination of choline, putrescine and cadaverine in boletus by cation exchange chromatography with suppressed conductivity detection. Samples were extracted with 7 mmol/L methanesulfonic acid solution, then filtered through a membrane, and purified by a reversed phase solid phase extraction column. Choline, putrescine, cadaverine and coexisting ions in the samples were separated well on the IonPac CS17 cation exchange column (250 mm×4 mm). The mobile phase was 7 mmol/L methanesulfonic acid solution. All analytes could be eluted from the column in 25 min. The limits of detection (S/N=3) of choline, putrescine and cadaverine were 0.002, 0.002 and 0.003 mg/L, respectively. Moreover, they all had wide linearity ranges (0.01-10 mg/L) and satisfactory recoveries (91.6%-100.2%). This method is suitable for the determination of choline, putrescine and cadaverine in boletus, and has good separation performance, high selectivity and sensitivity.
byDalian Institute of Chemical
Physics,CASNational Chromatographic R. and A.
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