Extraction High-performance Liquid Chromatography Research Articles

Determination of quinolone antibiotics in surface water by MnFe2O4@TiO2 magnetic solid phase extraction-high performance liquid chromatography

The magnetic solid phase extraction material (MnFe2O4@TiO2) was prepared by coating TiO2 on MnFe2O4 through an in-situ formation method. The structure and properties of MnFe2O4@TiO2 were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), nitrogen adsorption–desorption experiment, and vibrating sample magnetometer (VSM). The conditions for magnetic solid phase extraction (MSPE) of quinolone antibiotics were optimized, and an MSPE-HPLC method was established to determine quinolone antibiotics in water samples. The optimal conditions for MSPE are MnFe2O4@TiO2 amount of 15 mg, extraction time of 15 min, 5 mL of methanol solution with 20 % ammonia as eluent, and elution time of 1 min. Under the optimal conditions, 50 mL 0.1 mg/L mixed standard solutions of fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin have achieved enrichment multiples of 67.8, 72.1, 59.6, 55.8, and 60.7, respectively. The linear range of five antibiotics determined by MSPE-HPLC is 0.004–1 mg/L with the relative standard deviations (RSDs) of 2.1 %–4.9 % and the limits of detection (LODs) of 0.0006–0.0020 mg/L. The method is applied to the determination of the five antibiotics in rice paddy water and fish pond water; the recoveries range from 78.9 to 105.8 %, and the RSDs (n = 5) are 3.6 %–8.7 %.

Content of secondary metabolites and antioxidant activities of Lonicera japonica flowers at different developmental stages from Shandong province

This study established an ultrasound-assisted extraction-high performance liquid chromatography method for simulta-neously determinining the content of 11 bioactive compounds including iridoids, phenolic acids, and flavonoids in Lonicera japonica flowers. The flowers at six stages from the rice bud stage(ML) to the golden flower stage(JH) of L. japonica varieties 'Sijuhua' and 'Beihua No.1' in two planting bases in Shandong province were collected. The established method was employed to determine the content of 11 target compounds, on the basis of which the dynamics of active components in L. japonica sampels during different development stages was investigated. The correlation analysis was carried out to reveal the correlations of the content of iridoids, phenolic acids, and flavonoids. Furthermore, the antioxidant activities of samples at different developmental stages were determined, and the relationship between antioxidant activity and chemical components was analyzed by the correlation analysis. The results showed that the total content of the 11 components in 'Sijihua' changed in a "W" pattern from the ML to JH, being the highest at the ML and the second at the slight white stage(EB). The total content of 11 compounds in 'Beihua No.1' was the highest at the ML and decreased gra-dually from the ML to JH. The samples of 'Sijihua' had higher content of iridoids and lower content of phenolic acids than those of 'Beihua No.1'. The content of flavonoids and phenolic acids showed a positive correlation(R~2=0.90, P<0.05) in 'Sijihua' but no obvious correlation in 'Beihua No.1'. The antioxidant activity and phenolic acid content showed positive correlations, with the determination coefficients(R~2) of 0.84(P<0.05) in 'Beihua No.1' and 0.73(P<0.05) in 'Sijihua'. The antioxidant activity of both varieties was the strongest at the ML and the second at the EB. This study revealed that the content dynamics of iridoids, phenolic acids, and flavonoids in 'Sijihua' and 'Beihua No.1' cultivated in Shandong province during different developmental stages. The results indicated that the antioxidant activity of L. japonica flowers was significantly correlated with the content of phenolic acids at different deve-lopmental stages, which provided a basis for determining the optimum harvest time of L. japonica flowers.

Covalent organic framework/layered double hydroxide composite-coated poly(ether ether ketone) jacket for stir bar sorptive extraction of Sudan dyes.

A novel coating for stir bar sorptive extraction was developed by growing a covalent organic framework, TpPa-1 (derived from phenylenediamine and 1,3,5-trimethylphloroglucinol), onto the surface of Ni-Al layered double hydroxide. Using a poly(ether ether ketone) tube as the supporting substrate, a TpPa-1/layered double hydroxide-coated stir bar was fabricated and demonstrated excellent extraction performance for Sudan dyes. Notably, its extraction efficiency significantly exceeded that of stir bars modified with only TpPa-1 or Ni-Al layered double hydroxide. Based on this innovative coating, a stir bar sorptive extraction-high performance liquid chromatography method was established. This method exhibited low limits of detection (0.04-0.08ng/mL) for the analysis of Sudan dyes. It also featured a wide linear range (0.25-100 or 200ng/mL) and demonstrated good repeatability with relative standard deviations ≤6.22%. The recoveries obtained for spiked lake water and chili powder samples were 93.5%-105.2% and 87.8%-100.6%, respectively, demonstrating the practical potential of the developed method for detecting trace Sudan dyes in real samples.

Color components determination and full-length comparative transcriptomic analyses reveal the potential mechanism of carotenoid synthesis during Paphiopedilum armeniacum flowering.

Paphiopedilum armeniacum (P. armeniacum), an ornamental plant native to China, is known for its distinctive yellow blossoms. However, the mechanisms underlying P. armeniacum flower coloration remain unclear. We selected P. armeniacum samples from different flowering stages and conducted rigorous physicochemical analyses. The specimens were differentiated based on their chemical properties, specifically their solubilities in polar solvents. This key step enabled us to identify the main metabolite of flower color development of P. armeniacum, and to complete the identification by High-performance liquid chromatography (HPLC) based on the results. Additionally, we employed a combined approach, integrating both third-generation full-length transcriptome sequencing and second-generation high-throughput transcriptome sequencing, to comprehensively explore the molecular components involved. We combined physical and chemical analysis with transcriptome sequencing to reveal that carotenoid is the main pigment of P. armeniacum flower color. Extraction colorimetric method and HPLC were used to explore the characteristics of carotenoid accumulation during flowering. We identified 28 differentially expressed carotenoid biosynthesis genes throughout the flowering process, validated their expression through fluorescence quantification, and discovered 19 potential positive regulators involved in carotenoid synthesis. Among these candidates, three RCP2 genes showed a strong potential for governing the PDS and ZDS gene families. In summary, our study elucidates the fundamental mechanisms governing carotenoid synthesis during P. armeniacum flowering, enhancing our understanding of this process and providing a foundation for future research on the molecular mechanisms driving P. armeniacum flowering.

Rapid and green quantification of phloridzin and trilobatin in Lithocarpus litseifolius (Hance) Chun (sweet tea) using an online pressurized liquid extraction high-performance liquid chromatography at equal absorption wavelength method.

Sweet tea is a functional herbal tea with anti-inflammatory, anti-diabetic, and other effects, in which phloridzin and trilobatin are two functional compounds. However, the current methods for their quantification are time-consuming, costly, and environmentally unfriendly. In this paper, we propose a rapid method that integrates online pressurized liquid extraction and high-performance liquid chromatography featuring a superficially porous column for fast separation. Moreover, we employ an equal absorption wavelength method to eliminate using multiple standard solutions and relative calibration factors. Our verification process corroborated the technique's selectivity, accuracy, precision, linearity, and detection limitations. Separately, our methodology demonstrated excellent analytical efficiency, cost-effectiveness, and environmental friendliness. Practical application using six distinct batches of sweet tea samples yielded results in congruence with the external standard method. The analytical rate of this technique is up to over 18 times faster than traditional methods, and organic solvent consumption has been reduced to less than 1.5 mL. Therefore, this method provides a valuable way to achieve quality control and green analysis of sweet tea and other herbal teas.

Online solid phase extraction high-performance liquid chromatography – Isotope dilution – Tandem mass spectrometry quantification of organophosphate pesticides, synthetic pyrethroids, and selected herbicide metabolites in human urine

Analytical methods to quantify pesticide biomarkers in human population studies are critical for exposure assessment given the widespread use of pesticides for pest and weed control and their potential for affecting human health. We developed a method to quantify, in 0.2 mL of urine, concentrations of 10 pesticide biomarkers: four organophosphate insecticide metabolites (3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-6-methyl-4-pyrimidinol, para-nitrophenol, malathion dicarboxylic acid); five synthetic pyrethroid insecticide metabolites (4-fluoro-3-phenoxybenzoic acid, 3-phenoxybenzoic acid, cis and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid); and the herbicide 2,4-dichlorophenoxyacetic acid.he method is based on enzymatic hydrolysis of conjugated urinary metabolites, extraction and pre-concentration of the deconjugated metabolites using automated online solid-phase extraction, and separation and quantification using liquid chromatography-isotope dilution tandem mass spectrometry.Depending on the analyte, method detection limits were 0.1–0.6 ng/mL; mean accuracy, calculated as spike recoveries, was 91–102%, and total precision, given as percent variation coefficient, was 5.9–11.5%. Percent differences associated with three freeze-thaw cycles, 24-h benchtop storage, and short-term processed sample stability were <14%.Method suitability was assessed by recurring successful participation in external quality assessment schemes and by analyzing samples from subjects with suspected exposure to pesticides (n = 40) or who self-reported consuming an organic diet (n = 50). Interquartile ranges were considerably lower for people consuming an organic diet than for those potentially exposed for cis-DCCA (0.37 ng/mL vs 0.75 ng/mL), trans-DCCA (0.88 ng/mL vs 1.78 ng/mL) and TCPy (1.81 ng/mL vs 2.48 ng/mL). This method requires one-fifth of the sample used in our previous method and is suitable for assessing background exposures to select pesticides in large human populations and for studies with limited sample volumes.

Nanoconfinement of functionalized ionic liquid for enhanced adsorption and rapid sensitive detection of phenylurea herbicides in food and environmental samples

The novel ILs@CNTs was synthesized by encapsulating task-specific ionic liquids (ILs) within carbon nanotubes (CNTs) derived from ZIF-67. These hybrid materials served as multifunctional adsorbents enabling simultaneous sorptive removal, sensitive detection, molecular sieve selection, and magnetic separation. In contrast to pristine CNTs, ILs@CNTs demonstrate significantly enhanced adsorption of phenylurea herbicides (PUHs). The complex interactions between ILs@CNTs and PUHs were comprehensively analyzed using a combination of experimental results and theoretical calculations. Furthermore, a magnetic solid phase extraction-high performance liquid chromatography (MSPE-HPLC) method was developed for the determination of multiple trace PUHs in real samples. The method exhibited lower detection limits (0.02–0.03 μg L−1) and higher enrichment factors (131 < EFs < 185). Interestingly, a portable lab-in-a-syringe device was developed to facilitate rapid on-site extraction and enrichment of PUHs. Additionally, the developed methods successfully applied in river water, tea drinks, and cucumber samples, highlighting its substantial potential for rapid PUH detection.

Simultaneous determination of five lignans from Schisandra chinensis by matrix solid-phase dispersion extraction-high performance liquid chromatography

The kidney-shaped, red-colord fruit from the plant, Schisandra chinensis (Turcz.) Baill, which belongs to the Schisandraceae family, is among the most popular remedies used in traditional Chinese medicine. The English name of the plant is "Chinese magnolia vine". It has been used in Asia since ancient times to treat a variety of ailments, including chronic cough and dyspnea, frequent urination, diarrhea, and diabetes. This is because of the wide range of bioactive constituents, such as lignans, essential oils, triterpenoids, organic acids, polysaccharides, and sterols. In some cases, these constituents affects the pharmacological efficacy of the plant. Lignans with a dibenzocyclooctadiene-type skeleton are considered to be the major constituents and main bioactive ingredients of Schisandra chinensis. However, because of the complex composition of Schisandra chinensis, the extraction yields of lignans are low. Thus, it is particularly important to study pretreatment methods used during sample preparation for the quality control of traditional Chinese medicine. Matrix solid-phase dispersion extraction (MSPD) is a comprehensive process involving destruction, extraction, fractionation, and purification. The MSPD method is simple, it requires only a small number of samples and solvents, it does not require any special experimental equipments or instruments, and it can be used to prepare liquid, viscous, semi-solid, solid samples. In this study, a method combining matrix solid-phase dispersion extraction with high performance liquid chromatography (MSPD-HPLC) was established for the simultaneous determination of five lignans (schisandrol A, schisandrol B, deoxyschizandrin, schizandrin B, and schizandrin C) in Schisandra chinensis. The target compounds were separated on a C18 column with a gradient elution of 0.1% (v/v) formic acid aqueous solution and acetonitrile as the mobile phases, and detection was performed at a wavelength of 250 nm. First, the effects of 12 adsorbents, including silica gel, acidic alumina, neutral alumina, alkaline alumina, Florisil, Diol, XAmide, Xion, and the inverse adsorbents, C18, C18-ME, C18-G1, and C18-HC, on the extraction yields of lignans were investigated. Second, effects of the mass of the adsorbent, the type of eluent, and volume of eluent on the extraction yields of lignans were investigated. Xion was chosen as an adsorbent for MSPD-HPLC analysis of lignans from Schisandra chinensis. Optimization of the extraction parameters showed that the MSPD method had a high lignan extraction yield with Schisandra chinensis powder (0.25 g) as a fixed value, Xion as the adsorbent (0.75 g), and methanol as the elution solvent (15 mL). Analytical methods were developed for five lignans from Schisandra chinensis and these methods showed good linearity (correlation coefficients (R2)≥ 0.9999) for each target analyte. The limits of detection and quantification ranged from 0.0089 to 0.0294 μg/mL and 0.0267 to 0.0882 μg/mL, respectively. Lignans were tested at low, medium, and high levels. The average recovery rates were 92.2% to 111.2%, and the relative standard deviations were 0.23% to 3.54%. Both intra-day and inter-day precisions were less than 3.6%. Compared with hot reflux extraction and ultrasonic extraction methods, MSPD has the advantages of combined extraction and purification, being less time-consuming, and requiring lower solvent volumes. Finally, the optimized method was successfully applied to analyze five lignans from Schisandra chinensis samples from 17 cultivation areas.

Determination of 15 carbonyl compounds in soil using improved solid phase extraction-high performance liquid chromatography

An improved solid phase extraction (SPE)-high performance liquid chromatography method was established to determine 15 carbonyl compounds, namely, formaldehyde (FOR), acetaldehyde (ACETA), acrolein (ACR), acetone (ACETO), propionaldehyde (PRO), crotonaldehyde (CRO), butyraldehyde (BUT), benzaldehyde (BEN), isovaleraldehyde (ISO), n-valeraldehyde (VAL), o-methylbenzaldehyde (o-TOL), m-methylbenzaldehyde (m-TOL), p-methylbenzaldehyde (p-TOL), n-hexanal (HEX), and 2,5-dimethylbenzaldehyde (DIM), in soil. The soil was ultrasonically extracted with acetonitrile, and the extracted samples were derivatized with 2,4-dinitrophenylhydrazine (2,4-DNPH) to generate stable hydrazone compounds. The derivatized solutions were cleaned using an SPE cartridge (Welchrom® BRP) packed with N-vinylpyrrolidone/divinylbenzene copolymer. Separation was performed on an Ultimate® XB-C18 column (250 mm×4.6 mm, 5 μm), isocratic elution was performed with acetonitrile-water (65∶35, v/v) as the mobile phase, and detection was performed at a wavelength of 360 nm. The 15 carbonyl compounds in the soil were then quantified using an external standard method. The proposed method improves the sample processing method described in the environmental standard HJ 997-2018: Soil and sediment-Determination of carbonyl compounds-High performance liquid chromatography. A series of experiments revealed the following optimal conditions for soil extraction: acetonitrile as the extraction solvent, extraction temperature of 30 ℃, and extraction time of 10 min. The results showed that the purification effect of the BRP cartridge was significantly better than that of the conventional silica-based C18 cartridge. The 15 carbonyl compounds showed good linearities, and all correlation coefficients were above 0.996. The recoveries ranged from 84.6% to 115.9%, the relative standard deviations (RSDs) ranged from 0.2% to 5.1%, and the detection limits were 0.02-0.06 mg/L. The method is simple, sensitive, and suitable for the accurate quantitative analysis of the 15 carbonyl compounds in soil specified in HJ 997-2018. Thus, the improved method provides reliable technical support for studying the residual status and environmental behavior of carbonyl compounds in soil.

Genome mining and chemical characterization of a new cyclic lipopeptide associated with MDN-0066 from Pseudomonas moraviensis HN2 cultured in a valine-rich medium.

A new cyclic lipopeptide (CLP) MDN-0066-β (1) and MDN-0066 (2) were isolated and characterized from the bacterial cultures of P. moraviensis HN2 in this study. The CLPs were purified by solid-phase extraction (SPE) and reversed-phase high performance liquid chromatography (RP-HPLC). Moreover, chemical structures of two CLPs were characterized by genome mining and analysis, nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HR-MS), Marfey's method and (C-H)α NMR fingerprint matching approach. MDN-0066 (2) has an amino acid sequence of L-Leu1, D-Glu2, D-allo-Thr3, D-Leu4, D-Leu5, D-Ser6, L-Leu7, L-Ile8 linked to a saturated C10 β-hydroxyl fatty acid moiety (R-configuration for 3-OH). The new CLP MDN-0066-β (1) differs MDN-0066 (2) in the 8th position of L-valine in its peptide moiety, this variation in structure could be attributed to the supplement of L-valine in the cultural medium during liquid fermentation. Further antimicrobial tests showed that the two CLPs display moderate antagonistic activity against Staphylococcus aureus and Escherichia coli.

Accurate varietal classification and quantification of key quality compounds of grape extracts using the absorbance-transmittance fluorescence excitation emission matrix (A-TEEM) method and machine learning

Rapid and accurate quantification of grape berry phenolics, anthocyanins and tannins and identification of grape varieties are both important for effective quality control of harvesting and initial processing for winemaking. Current reference technologies, including High-Performance Liquid Chromatography (HPLC), can be rate-limiting and too complex and expensive for effective field operations. In this paper, we analyse robotically prepared grape extracts from several key varieties (n = Calibration/n = Prediction samples), including Cabernet-Sauvignon (64/10), Grenache (16/4), Malbec (14/4), Merlot (56/10), Petite Sirah (52/10), Pinot noir (54/8), Syrah (20/2), Teroldego (14/2) and Zinfandel (62/12). Key phenolic and anthocyanin parameters measured by HPLC included Catechin, Epicatechin, Quercetin Glycosides, Malvidin 3-glucoside, Total Anthocyanins and Polymeric Tannins. Split samples diluted 50-fold in 50 % EtOH pH 2 were analysed in parallel using the A-TEEM method following Multi-block Data Fusion of the absorbance and unfolded EEM data. A-TEEM chemical data were calibrated (n = 390) using Extreme Gradient Boosting (XGB) Regression and evaluated based on the Root Mean Square Error of the Prediction (RMSEP), the Relative Error of Prediction (REP) and Coefficient of Variation (R2P) of the Prediction data (n = 62). The regression results yielded an average Relative Error of Prediction (REP) of 5.89 ± 2.47 % and an R2P of 0.941 ± 0.025. While we consider the REP values to be in the acceptable range at significantly &lt; 10 %, we acknowledge that both the grape extraction method repeatability and HPLC reference method sample repeatability (5-8 % RSD) likely constituted the major sources of variation compared to the A-TEEM instrumental sample repeatability (&lt; 2 % RSD). The varietal classification was analysed using Agglomerative Hierarchical Cluster Analysis (HCA) and XGB discrimination analysis of the multi-block data. The classification results yielded 100 % True Positive and True Negative responses for the Calibration and Prediction Data for all tested varieties. We conclude that the A-TEEM method requires a minimum of sample preparation and rapid acquisition times (&lt; 1 min) and can serve as an accurate secondary method for both grape varietal identification and phenolic quantification. Importantly, the software application of the regression and classification models can be effectively automated for operators.

Preparation of magnetic molybdenum disulfide for the extraction of neonicotinoid insecticides from environmental water samples

In this study, magnetic molybdenum disulfide hybrid composites (Fe3O4/MoS2) were successfully synthesized by in situ fabrication method and firstly applied as magnetic adsorbent for extracting neonicotinoid insecticides from environmental water samples. The Fe3O4/MoS2 composites were characterized in detail by scanning electron microscope, fourier transform infrared, X-ray diffraction and vibrating sample magnetometer, and possessed the faster adsorption capacity towards neonicotinoid insecticides (only 10 min). The parameters (solution pH, amounts of adsorbents, adsorption time, elution conditions and sample volume) effecting the performance of magnetic solid-phase extraction were carefully investigated. Under the optimal conditions, the magnetic solid-phase extraction-high performance liquid chromatography method based on Fe3O4/MoS2 composites for enriching and detecting neonicotinoid insecticides in environmental water samples was established. The good linearity (0.01–10 μg/mL) with correlation coefficients between 0.9949 and 0.9999 was obtained. The limits of detection and the limits of quantifications were 0.48–0.67 ng/mL and 1.44–2.02 ng/mL, respectively. With spiked at three different concentration levels (50, 100,500 ng/mL), the recovery was 66.0–91.3 % with relative standard deviations from 1.4 % to 8.3 %. These data demonstrated that the developed method was highly sensitive, repeatable and easily operated. Also, this study provided new adsorbents for other trace pollutants in the environment.

Analysis of parabens in environmental water samples by covalent organic framework-based magnetic solid-phase extraction-high performance liquid chromatography

Parabens are a class of antimicrobial preservatives that are widely used in cosmetics, pharmaceuticals, and food products because of their ease of production, antimicrobial effect, and low price. The widespread use of these parabens, poses potential risks to human health. Therefore, it is necessary to establish a simple and rapid method for the detection of parabens. The large number of substrate interferences in complex samples is an important factor affecting the sensitivity of analytical methods. Magnetic solid-phase extraction (MSPE) has received much attention because of its advantages of easy operation, short extraction time, small sample amount, low cost, and environmental friendliness. Covalent organic frameworks (COFs) with high crystallinity, high specific surface area, adjustable pore size, regular porosity, as well as high chemical and thermal stability are now widely used in separation and analysis. Therefore, a sample pretreatment method combining MSPE and COF for the analysis of parabens in complex matrices is very promising. A magnetic covalent organic framework, Fe3O4@TbBd, was successfully synthesized by the Schiff base reaction of 1,3,5-triformylbenzene (Tb) and benzidine (Bd) at room temperature using Fe3O4 nanoparticles as magnetic cores. Characterization by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) measurements, etc. revealed that the magnetic COF has high magnetic responsiveness, as well as good thermal and chemical stability, which make it an ideal adsorbent for the MSPE of parabens. Some factors related to the extraction efficiency, including the amount of adsorbent, extraction time, pH, desorption solvent, desorption time, and number of desorption were systematically investigated. A method involving MSPE and high performance liquid chromatography-ultraviolet detection (HPLC-UV) based on the Fe3O4@TbBd was developed for the determination of four parabens (ethylparaben, propylparaben, butylparaben, and benzylparaben) in environmental water samples. Under the optimal extraction conditions, the method showed good linearities. The limits of detection and limits of quantification were 0.2-0.4 μg/L and 0.7-1.4 μg/L for the four analytes, respectively. The recoveries at three spiked levels were in the range of 86.1%-110.8% with intra-day and inter-day RSDs of less than 5.5% and 4.9%, respectively. The method was successfully applied to the determination of parabens in East Lake water, Yangtze water, and domestic wastewater. Ethyl paraben and propyl paraben were detected in domestic wastewater at the levels of 1.8 μg/L and 0.4 μg/L, respectively. The recoveries of the parabens at different spiked levels ranged from 80.7% to 117.5%, with RSDs of 0.2%-8.8%. The method has good potential for the determination of parabens in environmental water samples because of its operational simplicity, short extraction time, high sensitivity, and environmental friendliness.

Simultaneous determination of four antibiotics in human urine and hair samples employing a simple and efficient dispersive micro solid-phase extraction-high performance liquid chromatography.

Antibiotics containing azithromycin, amoxicillin, doxycycline, tetracycline, and azithromycin are widely utilized in the treatment of bacterial infections, and their determination in biological samples is critical to evaluate their side effects. A dispersive micro solid-phase extraction (DMSPE) as an efficient sample preparation was developed for the simultaneous extraction of the antibiotics in biological samples. For this purpose, chitosan@Fe3O4 nanoparticles were prepared as a green and magnetic sorbent based on a chemical coating of Fe3O4 nanoparticles with chitosan. The sorbent was compared with several sorbents such as ZnO NPs, CuO NPs, and Fe3O4 NPs to extract the antibiotics. In addition, effective factors for antibiotic extraction were evaluated and optimized using a central composite design and one factor at a time. The method has wide linearity in the concentration ranges of 2.1-800.0, 3.5-1000.0, 2.0-800.0, and 2.7-1000.0μgL-1 with an R-squared higher than 0.9958 for the determination of azithromycin, amoxicillin, doxycycline, and tetracycline, respectively. The limit of detection and limit of quantitation was lower than 1.1 and 3.5μgL-1, respectively. The relative standard deviations (RSDs) were also lower than 4.90% for the determination of the analytes at a concentration of 20.0µgL-1. High recoveries in the percentage range of 94.70-106.75%, with RSDs between 4.64 and 5.83%, were obtained to analyze spiked urine and hair samples. The DMSPE-HPLC-DAD procedure displayed various advantages for determining antibiotics, including simple operation, high recoveries, low sample solution and desorption solvent consumption, high preconcentration factors, proper determination time, and simple and inexpensive method of sorbent preparation.

Simultaneous Determination of Protoberberine Alkaloids Derived from Coptidis Rhizoma and Phellodendri Cortex in Pharmaceuticals by On-line Solid-Phase Extraction (SPE)—High Performance Liquid Chromatography with Ultraviolet Detection (HPLC-UV)

An automated on-line solid-phase extraction (SPE) high-performance liquid chromatography (HPLC) method was developed for the determination of six protoberberine alkaloids in compound Chinese medicines containing Coptidis Rhizoma and Phellodendri Cortex. The sample solution extracted by acidic-methanol was loaded into the constructed system directly to perform enrichment and the purification of the analytes was performed automatically. A cation-exchanged sorbent based on turbulent chromatography was employed for on-line SPE to remove macro and neutral matrix interferences from samples. The target alkaloids were retained on the SPE column and eluted onto the trapping C18 column by a mobile phase of methanol/500 mM ammonium acetate (85:15) at a flow rate of 0.3 mL/min. Ion pair reverse phase high-performance liquid chromatography was employed to complete the determination of six analytes. The results showed the linear correlation coefficients for all analytes were above 0.999. The peak area of relative standard deviation in reproducibility measurements were from 0.55% to 2.39%. Recovery measurements spiked at two levels were from 92.71% to 104.28%. The reported method was suitable for the determination of six active alkaloids in multicomponent Chinese medicines containing Coptidis rhizoma and Phellodendri cortex.

Simultaneous determination of raloxifene and tamoxifen using dispersive micro solid-phase extraction and HPLC method in real water, human hair and serum samples

ABSTRACT A sensitive determination procedure was presented for two anticancer drugs (tamoxifen and raloxifene) in real water and biological samples based on magnetic dispersive micro solid-phase extraction–high-performance liquid chromatography with an ultraviolet detector. Fe3O4 NPs@SiO2@TiO2 nanocomposite was synthesised as a magnetic sorbent by the sol-gel technique. The effective parameters in the procedure were optimised with an experimental design, including screening and optimisation steps. Under the optimum determination conditions, the procedure displayed wide linear ranges of 5.3–735.0 and 7.0–806.0 ng mL−1 with R-squared of 0.9916 and 0.9908, limit of detections of 1.6 and 2.1 ng mL−1 for the raloxifene and tamoxifen determination, respectively. The intra-day relative standard deviations were 3.76 and 3.59% for three times the raloxifene and tamoxifen measurements, respectively. The preconcentration factors for the raloxifene and tamoxifen determination with a concentration of 20 ng mL−1 were 506.1 and 546.7, respectively. The method was applied to analyse well water, tap water, and hair samples and determine raloxifene and tamoxifen simultaneously with recoveries between 88.5–96.4 and relative standard deviations lower than 8.4%. The method’s advantages for raloxifene and tamoxifen measurement included easy operation, low sorbent and desorption solvent consumption, simple sorbent preparation and separation, and suitable analysis time.

Determination of trans-4-hydroxy-2-alkenals in thermally treated soybean oil by SPE-HPLC

Trans-4-hydroxy-2-hexenal (4-HHE) and trans-4-hydroxy-2-nonenal (4-HNE) are secondary lipid peroxidation products in edible oils, which are cytotoxic and genotoxic. They could covalently bind with protein, phospholipids and DNA, further disrupting the normal function of liver, lung and brain. Derivation process was generally conducted during pretreatment before detection and quantification of 4-HHE and 4-HNE. However, the derivation procedures were time consuming and chemical degradation may occur during the process. Hence, this paper aims to establish a simple solid phase extraction-high performance liquid chromatography (SPE-HPLC) method to determine the 4-HHE and 4-HNE contents in thermally treated soybean oil. C18 solid phase extraction was applied in the pretreatment process. Firstly, the reliability of the method was evaluated. Good linearity was observed in the range of 0.1–0.5 μg/mL and 0.5–10 μg/mL for 4-HHE and 4-HNE. The limit of detection (LOD) of 4-HHE and 4-HNE were 0.0486 and 0.0129 μg/mL, respectively. And the limit of quantitation (LOQ) of 4-HHE and 4-HNE were 0.1458 and 0.0431 μg/mL, respectively. Recovery rate were in the range of 89.11%–91.58% and 71.83%–79.40% for 4-HHE and 4-HNE, respectively. The method achieved the extraction, purification and detection of 4-HHE and 4-HNE simultaneously and had the advantages of simple operation, effectiveness, high precision, good repeatability. Then, the method was applied to monitor the concentrations of 4-HHE and 4-HNE in soybean oil heated at 180 °C for 40 h. The contents of 4-HHE and 4-HNE were 0–0.32 μg/g and 0–6.97 μg/g, respectively, which provided guidance for evaluating health risks of thermally treated soybean oil during heating.

On-Line Solid Phase Extraction High Performance Liquid Chromatography Method Coupled With Tandem Mass Spectrometry for the Therapeutic Monitoring of Cannabidiol and 7-Hydroxy-cannabidiol in Human Serum and Saliva.

Cannabidiol is a novel antiseizure medication approved in Europe and the US for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome and tuberous sclerosis complex. We describe in this article a new and simple liquid chromatography-mass spectrometry method (LC-MS/MS) for the determination of cannabidiol and its active metabolite 7-hydroxy-cannabidiol in microvolumes of serum and saliva (50 μl), to be used as a tool for therapeutic drug monitoring (TDM) and pharmacokinetic studies. After on-line solid phase extraction cannabidiol, 7-hydroxy-cannabidiol and the internal standard cannabidiol-d3 are separated on a monolithic C18 column under gradient conditions. Calibration curves are linear within the validated concentration range (10–1,000 ng/ml for cannabidiol and 5–500 ng/ml for 7-hydroxy-cannabidiol). The method is accurate (intraday and interday accuracy within 94–112% for cannabidiol, 91–109% for 7-hydroxy-cannabidiol), precise (intraday and interday precision <11.6% for cannabidiol and <11.7% for 7- hydroxy-cannabidiol) and sensitive, with a LOQ of 2.5 ng/ml for cannabidiol and 5 ng/ml for 7-hydroxy-cannabidiol. The stability of the analytes was confirmed under different storage conditions. Extraction recoveries were in the range of 81–129% for cannabidiol and 100–113% for 7-hydroxy-cannabidiol. The applicability of the method to TDM was demonstrated by analysis of human serum and saliva samples obtained from patients with epilepsy treated with cannabidiol.

Distribution and Ecological Risk Assessment of Pharmaceuticals and Personal Care Products in Sediments of North Canal, China

The pollution of water bodies by pharmaceuticals and personal care products (PPCPs) has attracted widespread concern due to their widespread use and pseudo-persistence, but their effects on sediments are less known. In this study, solid-phase extraction-high performance liquid chromatography–tandem mass spectrometry (SPE-LC/MSMS) was used to investigate the occurrence and ecological risks of five typical pharmaceuticals and personal care products (PPCPs) in thirteen key reservoirs, sluices, dams, and estuaries in the Haihe River Basin. At the same time, the PPCP exchanges of surface water, groundwater, and sediments in three typical sections were studied. Finally, the PPCP’s environmental risk is evaluated through the environmental risk quotient. The results showed that the five PPCPs were tri-methoprazine (TMP), sinolamine (SMX), ibuprofen (IBU), triclosan (TCS), and caffeine (CAF). The average concentration of these PPCPs ranged from 0 to 481.19 μg/kg, with relatively high concentrations of TCS and CAF. The relationship between PPCPs in the surface sediments was analyzed to reveal correlations between SMX and TMP, CAF and IBU, CAF and TCS. The risk quotients (RQ) method was used to evaluate the ecological risk of the five detected PPCPs. The major contributors of potential environmental risks were IBU, TCS and CAF, among which all the potential environmental risks at the TCS samples were high risk. This study supplemented the research on the ecological risk of PPCPs in sediments of important reaches of the North Canal to reveal the importance of PPCP control in the North Canal and provided a scientific basis for pollution control and risk prevention of PPCPs.

Effective extraction of parabens from toothpaste by vortex-assisted liquid-phase microextraction based on low viscosity deep eutectic solvent

An efficient, green and reliable method, namely deep eutectic solvent-based vortex-assisted liquid-phase microextraction (DES-VALPME) was proposed for the rapid extraction and sensitive high performance liquid chromatography coupled with variable wavelength detector (HPLC-VWD) determination of methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) in toothpaste samples as a proof-of-concept example of trace analysis of personal care and cosmetic products. Compared with traditional DES suffering from higher viscosity, a class of six low viscosity DESs were synthesized by simply dissolving quaternary ammonium salts (hydrogen bond acceptors, HBAs) in methanol or ethanol (hydrogen bond donors, HBDs) at ambient temperature. Initial studies indicated that the DES consisting of tetrabutylammonium chloride (TBAC) and ethanol at a molar ratio of 1:5 achieved the highest extraction efficiency for all target analytes. The influence of type, molar ratio and volume of DES, extraction temperature and vortex time on the extraction efficiency was investigated and optimized systematically. Under the selected conditions, the method displayed satisfactory linearity in the range of 0.05–10 μg/g (R2 ≥ 0.9995), acceptable recoveries for the real samples (varied from 79.4% to 108.6%), good precision (with relative standard deviation ≤ 5.2 %), as well as lower limits of detection (in the range of 0.01–0.02 μg/g). This study demonstrates that the separation and determination of PBs with the developed DES-VALPME-HPLC-VWD technique is simple, efficient, sensitive and inexpensive.