Preparative isolation of arylbutanoid‐type phenol [(‐)‐rhododendrin] with peak tailing on conventional C18 column using middle chromatogram isolated gel column coupled with reversed‐phase liquid chromatography

Reversed‐phase liquid chromatography coupled with middle chromatogram isolated gel column was employed for the efficient preparative separation of the arylbutanoid‐type phenol [(‐)‐rhododendrin] from Saxifraga tangutica. Universal C18 (XTerra C18) and XCharge C18 columns were compared for (‐)‐rhododendrin fraction analysis and preparation. Although tailing and overloading occurred on the XTerra C18 column, the positively charged reversed‐phase C18 column (XCharge C18) overcame these drawbacks, allowing for favorable separation resolution, even when loading at a on a preparative scale (3.69 mg per injection). The general separation process was as follows. First, 365.0 mg of crude (‐)‐rhododendrin was enriched from 165 g Saxifraga tangutica extract via a middle chromatogram isolated gel column. Second, separation was performed on an XTerra C18 preparative column, from which 73.8 mg of the target fraction was easily obtained. Finally, the 24.0 mg tailing peak of (‐)‐rhododendrin on XTerra C18 column was selectively purified on the XCharge C18 analytical column. These results demonstrate that the tailing nonalkaloid peaks can be effectively used for preparative isolation on XCharge C18 columns.     

Three‐Dimensional Cuprous Lead Bromide Framework with Highly Efficient and Stable Blue Photoluminescence Emission

Considering the instability and low photoluminescence quantum yield (PLQY) of blue‐emitting perovskites, it is still challenging and attractive to construct single crystalline hybrid lead halides with highly stable and efficient blue light emission. Herein, by rationally introducing d¹⁰ transition metal into single lead halide as new structural building unit and optical emitting center, we prepared a bimetallic halide of [(NH₄)₂]CuPbBr₅ with new type of three‐dimensional (3D) anionic framework. [(NH₄)₂]CuPbBr₅ exhibits strong band‐edge blue emission (441 nm) with a high PLQY of 32 % upon excitation with UV light. Detailed photophysical studies indicate [(NH₄)₂]CuPbBr₅ also displays broadband red light emissions derived from self‐trapped states. Furthermore, the 3D framework features high structural and optical stabilities at extreme environments during at least three years. To our best knowledge, this work represents the first 3D non‐perovskite bimetallic halide with highly efficient and stable blue light emission.     

Determination of carbapenems in water samples by UHPLC–MS/MS

A rapid and reliable method for the detection of five carbapenems (biapenem, imipenem, doripenem, meropenem, and faropenem) in water was developed and validated. After acidification of water samples with acetic acid, carbapenems were isolated using a Bond Elut PPL cartridge. The target compounds were separated using ultra high performance liquid chromatography with a chromatographic run time of 5 min and detected on a triple quadrupole mass spectrometer operated in positive electrospray ionization and multiple reaction monitoring mode. Mean recoveries were in the range of 76.6–106.5%, with satisfactory intraday and interday relative standard deviations lower than 10.0 and 10.8%, respectively. The limits of detection and quantification were in the ranges of 0.05–0.2 µg/L and 0.1–0.5 µg/L, respectively, depending on the analyte. The proposed method was applied to the analysis of river samples and wastewater samples from swine farms, and no carbapenems were detected in the collected samples.     

Mycotoxins in spices and culinary herbs from Italy and Tunisia

Abstract

Spices and aromatic herbs can be contaminated with mycotoxins, since of their preharvest, postharvest, and storage conditions. In this study, 112 samples of different spices and aromatic herbs were evaluated for their mycotoxins content by HPLC-MS/MS in order to highlight their possible risk linked with human use. The results showed that mycotoxins were occasionally detected only in samples of coriander, laurel, mint, rosemary, and verbena. In both geographical origins a different contamination was detected. Among the investigated mycotoxins, AFB2, AFG1, AFG2, T2 and HT2 were detected, whereas none of the samples contained AFB1 and FB1. The co-occurrence of two toxins were observed for some samples of rosemary and verbena. This study indicates that it is essential minimize the toxins in agriculture, industry, and food-product manufacturing for the consumer health protection.     

Metabolomics of lung cancer: Analytical platforms and their applications

Lung cancer is the leading type of cancer worldwide in terms of the number of new cases and is responsible for the largest number of deaths due to poor prognosis and difficult early detection. Due to its ability to detect numerous small molecular metabolites simultaneously, metabolomics has been widely used for the assessment of global metabolic changes in a living organism to discover candidate biomarkers for cancer diagnosis, investigate the development of cancer, and provide insights into the underlying pathophysiology. This review will mainly describe recent developments in lung cancer metabolomics in terms of early‐stage detection, biomarker discovery and mechanism exploration by using nuclear magnetic resonance, liquid chromatography–mass spectrometry, gas chromatography–mass spectrometry, and capillary electrophoresis–mass spectrometry in the last 10 years. The sample collection and metabolite extraction methods are also summarized.     

Dual‐mode hydrophilic interaction normal phase and reversed phase liquid chromatography of polar compounds on a single column

Adopting a stationary phase convention circumvents problematic definition of the boundary between the stationary and the mobile phase in the liquid chromatography, resulting in thermodynamically consistent and reproducible chromatographic data. Three stationary phase definition conventions provide different retention data, but equal selectivity: (i) the complete solid phase moiety; (ii) the solid porous part carrying the active interaction centers; (iii) the volume of the inner column pores. The selective uptake of water from the bulk aqueous‐organic mobile phase significantly affects the volume and the properties of polar stationary phases. Some polar stationary phases provide dual‐mode retention mechanism in aqueous‐organic mobile phases, reversed‐phase in the water‐rich range, and normal‐phase at high concentrations of the organic solvent in water. The linear solvation energy relationship model characterizes the structural contributions of the non‐selective and selective polar interactions both in the water‐rich and organic solvent‐rich mobile phases. The inner‐pore convention provides a single hold‐up volume value for the retention prediction on the dual‐mode columns over the full mobile phase range. Using the dual‐mode monolithic polymethacrylate zwitterionic micro‐columns alternatively in each mode in the first dimension of two‐dimensional liquid chromatography, in combination with a short reversed‐phase column in the second dimension, provides enhanced sample information.     

Portable capillary liquid chromatography for pharmaceutical and illicit drug analysis

A newly developed portable capillary liquid chromatograph was investigated for the separation of various pharmaceutical and illicit drug compounds. The system consists of two high‐pressure syringe pumps capable of delivering capillary‐scale flow rates at pressures up to 10 000 psi. Capillary liquid chromatography columns packed with sub‐2 μm particles are housed in cartridges that can be inserted into the system and easily connected through high‐pressure fluidic contact points by simply applying a specific, predetermined torque rather than using standard fittings and less precise sealing protocols. Several over‐the‐counter analgesic drug separations are demonstrated, along with a simple online measurement of tablet dissolution. Twenty illicit drug compounds were also separated across six targeted drug panels. The results described in this study demonstrate the capability of this compact liquid chromatography instrument to address several important drug‐related applications while simplifying system operation, and greatly reducing solvent usage and waste generation essential for onsite analysis.     

Simultaneous enantioselective determination of omeprazole,rabeprazole, lansoprazole,and pantoprazole enantiomers in human plasma by chiral liquid chromatography–tandem mass spectrometry

Proton pump inhibitors, including omeprazole, rabeprazole, lansoprazole, and pantoprazole, achieved simultaneous enantioselective determination in the human plasma by chiral liquid chromatography–tandem mass spectrometry. The four corresponding stable isotope‐labeled proton pump inhibitors were adopted as the internal standards. Each enantiomer and the internal standards were extracted with acetonitrile containing 0.1% ammonia, then separated with a Chiralpak IC column (5 µm, 4.6 mm × 150 mm) within 10 min. The mobile phase was composed of acetonitrile–ammonium acetate (10 mM) containing 0.2% acetic acid (50:50, v/v). To quantify all enantiomers, an API 4000 tandem mass spectrometer was used, and multiple reaction monitoring transitions were performed on m/z 360.1→242.1, 384.1→200.1, 370.1→252.1, and 346.1→198.1, respectively. No significant matrix effect was observed for all analytes. The calibration curve for all enantiomers were linear from 1.25 to 2500 ng/mL. The precisions for intra‐ and inter‐run were < 14.2%, and the accuracy fell in the interval of –5.3 to 8.1%. Stability of samples was confirmed under the storage and processing conditions. The developed method was also suitable for separation and determination of ilaprazole enantiomers. The validated method combining the equilibrium dialysis method was applied to the protein binding ratio studies of four pairs proton pump inhibitor enantiomers in human plasma.     

[Hmim]PF6 enhanced the extraction of polycyclic aromatic hydrocarbons from soil with the QuEChERS method

To detect, identify, and quantify the polycyclic aromatic hydrocarbons (PAHs) released into the environment, the PAHs need to be isolated from the soil matrix. In this work, a modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method with ionic liquid was combined with liquid chromatography to identify 16 selected PAHs in soil. Ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim]PF₆) was applied as an extractant component to enhance the process. The [Hmim]PF₆ content in acetonitrile (ACN) was optimized. The [Hmim]PF₆ modified QuEChERS method has the advantages defined by its name and a similar recovery to other extraction methods reported in the literature. Adding [Hmim]PF₆ may eliminate the co-extract proportion and achieve a more effective extraction. Compared with ACN alone, the matrix effect (ME) of ACN containing 5% [Hmim]PF₆ was reduced by approximately 35%. Additionally, the ME of using ACN containing [Hmim]PF₆ without a clean-up procedure was similar to that of using ACN followed by a clean-up procedure. The recoveries of the QuEChERS method implemented with [Hmim]PF₆ ranged from 75.19% to 100.98%. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.86 to 4.51 µg/kg and from 2.87 to 15.13 µg/kg, respectively.