Combined AC‐electrokinetic effects: Theoretical considerations on a three‐axial ellipsoidal model

AC fields induce charges at the structural interfaces of particles or biological cells. The interaction of these charges with the field generates frequency‐dependent forces that are the basis for AC‐electrokinetic effects such as dielectrophoresis (DEP), electrorotation (ROT), electro‐orientation, and electro‐deformation. The effects can be used for the manipulation or dielectric single‐particle spectroscopy. The observation of a particular effect depends on the spatial and temporal field distributions, as well as on the shape and the dielectric and viscoelastic properties of the object. Because the effects are not mutually independent, combined frequency spectra are obtained, for example, discontinuous DEP and ROT spectra with ranges separated by the reorientation of nonspherical objects in the linearly and circularly polarized DEP and ROT fields, respectively. As an example, the AC electrokinetic behavior of a three‐axial ellipsoidal single‐shell model with the geometry of chicken‐red blood cells is considered. The geometric and electric problems were separated using the influential‐radius approach. The obtained finite‐element model can be electrically interpreted by an RC model leading to an expression for the Clausius–Mossotti factor, which permits the derivation of force, torque, and orientation spectra, as well as of equations for the critical frequencies and force plateaus in DEP and of the characteristic frequencies and peak heights in ROT. Expressions for the orientation in linearly and circularly polarized fields, as well as for the reorientation frequencies were also derived. The considerations suggested that the simultaneous registration of various AC‐electrokinetic spectra is a step towards the dielectric fingerprinting of single objects.     

On‐chip technology for single‐cell arraying,electrorotation‐based analysis and selective release

This paper reports a method for label‐free single‐cell biophysical analysis of multiple cells trapped in suspension by electrokinetic forces. Tri‐dimensional pillar electrodes arranged along the width of a microfluidic chamber define actuators for single cell trapping and selective release by electrokinetic force. Moreover, a rotation can be induced on the cell in combination with a negative DEP force to retain the cell against the flow. The measurement of the rotation speed of the cell as a function of the electric field frequency define an electrorotation spectrum that allows to study the dielectric properties of the cell. The system presented here shows for the first time the simultaneous electrorotation analysis of multiple single cells in separate micro cages that can be selectively addressed to trap and/or release the cells. Chips with 39 micro‐actuators of different interelectrode distance were fabricated to study cells with different sizes. The extracted dielectric properties of Henrietta Lacks, human embryonic kidney 293, and human immortalized T lymphocytes cells were found in agreements with previous findings. Moreover, the membrane capacitance of M17 neuroblastoma cells was investigated and found to fall in in the range of 7.49 ± 0.39 mF/m².     

1H and 13C NMR analysis of 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamido‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamide derivatives

The complete assignment of the ¹H and ¹³C NMR spectra of various 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamide‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamides with p‐methoxy, o‐chloro and m‐chloro substituents is reported. Copyright © 2013 John Wiley & Sons, Ltd.     

Development of an improved online comprehensive hydrophilic interaction chromatography × reversed‐phase ultra‐high‐pressure liquid chromatography platform for complex multiclass polyphenolic sample analysis

In this study, an improved online comprehensive two‐dimensional liquid chromatography platform coupled to tandem mass spectrometry was developed for the analysis of complex polyphenolic samples. A narrowbore hydrophilic interaction chromatography column (150 × 2.0 mm, 3.0 μm, cross‐linked diol) was employed in the first dimension, while a reversed‐phase column based on monodisperse sub‐2 μm fully porous particles (50 × 3.0 mm, 1.9 μm d.p.) with high surface area (410 m²/g) was employed in the second dimension. The combination of a trapping column modulation interface with the high retentive fully porous monodisperse reversed‐phase column in the second dimension resulted in higher peak capacity values (1146 versus 867), increased sensitivity, sharper and more symmetrical peaks in comparison with a conventional loop‐based method, with the same analysis time (70 min). The system was challenged against a complex polyphenolic extract of a typical Italian apple cultivar, enabling the simultaneous separation of multiple polyphenolic classes, including oligomeric procyanidins, up to degree of polymerization of 10. Hyphenation with an ion trap time‐of‐flight mass spectrometer led to the tentative identification of 121 analytes, showing how this platform could be a powerful analytical tool for the accurate profiling of complex polyphenolic samples.     

Intracellular potassium under osmotic stress determines the dielectrophoresis cross‐over frequency of murine myeloma cells in the MHz range

Dielectrophoresis (DEP) has been widely studied for its potential as a biomarker‐free method of sorting and characterizing cells based upon their dielectric properties. Most studies have employed voltage signals from ∼1 kHz to no higher than ∼30 MHz. Within this range a transition from negative to positive DEP can be observed at the cross‐over frequency f_x01. The value of f_x01 is determined by the conductivity of the suspending medium, as well as the size and shape of the cell and the dielectric properties (capacitance, conductivity) of its plasma membrane. In this work DEP measurements were performed up to 400 MHz, where the transition from positive to negative DEP can be observed at a higher cross‐over frequency f_x02. SP2/O murine myeloma cells were suspended in buffer media of different osmolarities and measurements taken of cell volume, f_x01 and f_x02. Potassium‐binding benzofuran isophthalate (PBFI), a potassium‐sensitive fluorophore, and flow cytometry was employed to monitor relative changes in intracellular potassium concentration. In agreement with theory, it was found that f_x02 is independent of the cell parameters that control f_x01 and is predominantly determined by intracellular conductivity. In particular, the value of f_x02 is highly correlated to that of the intracellular potassium concentration.     

Dithienylmethanone‐Based Cross‐Conjugated Polymer Semiconductors: Synthesis,Characterization, and Application in Field‐Effect Transistors

Herein, we report the synthesis, characterization, and field‐effect properties of two cross‐conjugated dithienylmethanone (DMO)‐based alternating polymers, namely, PDMO‐S and PDMO‐Se . Both polymers possess high thermal stability, good solubility, and broad absorption spectra. Their electrochemical properties were investigated using cyclic voltammetry, indicating that PDMO‐Se has higher HOMO/LUMO energy levels of −5.49/−3.49 eV than −5.57/−3.58 eV of PDMO‐S . The two polymers exhibited promising charge transport properties with the highest hole mobility of 0.12 cm² V⁻¹ s⁻¹ for PDMO‐S and 0.025 cm² V⁻¹ s⁻¹ for PDMO‐Se . AFM and 2D‐GIXRD analyses demonstrated that the PDMO‐S formed lamellar, edge‐on packing thin film with close π‐π stacking. These findings suggest that cross‐conjugated polymers might be potential semiconducting materials for low‐cost and flexible organic electronics. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1012–1019     

Ionic metallo‐Schiff base polymers of VO2+, Zn2+ and Cu2+: Synthesis,characterization and solid‐state conductivity

The viologen‐type dialdehyde of [N,N′‐bis(methylsalicylaldehyde)‐4,4′‐bipyridinium] dichloride (DA) was synthesized by reacting 5‐chloromethylsalicylaldehyde and 4,4′‐bipyridine. Then a new polymeric Schiff base ligand (PSBL) was synthesized by the condensation reaction of ethylenediamine and DA in methanol under reflux conditions. Afterwards, new ionic metallo‐Schiff base polymers (IMSPs) were synthesized by reacting PSBL with VO(acac)₂, ZnCl₂ and CuCl₂ via coordination chelation. DA, PSBL and IMSPs were characterized using various analytical methods and spectral techniques. The solid‐state electrical conductivities of PSBL and IMSPs were studied. The electrical conductivity of these polymers at 300 K ranged from 1.30 × 10^?5 to 4.52 × 10^?10 Ω^?1 m^?1, which means they are potential organic and metallo‐organic semiconductors.     

New less toxic zeolite‐encapsulated Cu(II) complex nanomaterial for dual applications in biomedical field and wastewater remediation

A new dual‐functional Cu(II) complex and its nanohybrid form encapsulated into NaY zeolite cavities were synthesized. The synthesized compounds were characterized using elemental analyses, X‐ray fluorescence, infrared, ¹H NMR, electronic, electron spin resonance and mass spectra, powder X‐ray diffraction, surface area and transmission electron microscopy in addition to conductivity and magnetic susceptibility measurements. The encapsulated Cu(II) complex was catalytically tested for degradation of industrial wastewater. The decolorization and mineralization results indicate that the Cu(II) complex encapsulated into zeolite host is an effective heterogeneous catalyst for real industrial wastewater remediation. In addition, both free and encapsulated Cu(II) complexes were tested as anti‐microbial and anti‐tumour agents. The results show that the Cu(II) complex encapsulated into zeolite has a high activity (IC₅₀ = 14.4 μg ml^?1). The results of in vivo toxicity experiments indicate that the Cu(II) complex encapsulated into zeolite is a less toxic biocompatible material (LD₅₀ = 1245 mg kg^?1). The catalytic properties, cytotoxicity and toxicity of the new nanohybrid Cu(II) complex encapsulated into zeolite make it a promising eco‐friendly and biocompatible material for water remediation and biomedical applications.     

35Cl NQR studies of 1‐chloro‐2,4‐dinitrobenzene and 1,2‐dichloro‐3‐nitrobenzene as a function of pressure and temperature

The temperature and pressure dependences of ³⁵Cl nuclear quadrupole resonance (NQR) frequency and spin–lattice relaxation time (T₁) were investigated for 1‐chloro‐2,4‐dinitrobenzene and 1,2‐dichloro‐3‐nitrobenzene. T₁ was measured in the temperature range 77–300 K. Furthermore, the NQR frequency (ν) and T₁ for these compounds were measured as a function of pressure up to 5.1 kbar at 300 K. Relaxation was found to be due to the torsional motion of the molecule and the reorientation motion of the nitro group. By analysing the temperature dependence of T₁, the activation energy for the reorientation motion of the nitro group was obtained. The temperature dependence of the average torsional lifetimes of the molecules and the transition probabilities W₁ and W₂ for the Δm = ±1 and Δm = ±2 transitions, were also obtained. Both compounds showed a non‐linear variation of NQR frequency with pressure. The pressure coefficients were observed to be positive. A thermodynamic analysis of the data was carried out to determine the constant‐volume temperature coefficients of the NQR frequency. The spin–lattice relaxation time T₁ for both the compounds was found to be weakly dependent on pressure, showing that the relaxation is mainly due to the torsional motions. Copyright © 2002 John Wiley & Sons, Ltd.     

Preparation of dummy‐imprinted polymers by Pickering emulsion polymerization for the selective determination of seven bisphenols from sediment samples

The dummy molecularly imprinted polymers were prepared by Pickering emulsion polymerization. 4,4′‐(1‐Phenylethylidene) bisphenol was selected as the dummy template to avoid the leakage of the target bisphenols. The microsphere particles were characterized by scanning electron microscopy and nitrogen adsorption–desorption measurements, demonstrating that the regular‐shaped and medium‐sized particles (40–70 μm) were obtained with a specific surface area of 355.759 m²/g and a total pore volume of 0.561 cm³/g. The molecular imprinting properties of the particles were evaluated by static adsorption and chromatographic evaluation experiments. The association constant and maximum adsorption amount of bisphenol A were 0.115 mmol/L and 3.327 μmol/g using Scatchard analysis. The microsphere particles were then used as a solid‐phase extraction sorbent for selective extraction of seven bisphenols. The method of dummy molecularly imprinted solid‐phase extraction coupled with high‐performance liquid chromatography and diode array detection was successfully established for the extraction and determination of seven bisphenols from environmental sediment samples with method detection limits of 0.6–1.1 ng/g. Good recoveries (75.5–105.2%) for sediment samples at two spiking levels (500 and 250 ng/g) and reproducibility (RSDs < 7.7%, n = 3) were obtained.     

Field‐amplified sample injection combined with CE for the enantiodetermination of cathinones in urine samples

This work presents a capillary electrophoresis methodology for the enantiodetermination of cathinones in urine employing a liquid–liquid extraction sample pretreatment. The cathinones were enantioseparated by adding a mixture of 8 mM 2‐hydroxypropyl β‐cyclodextrin and 5 mM β‐cyclodextrin to the background electrolyte, which consists of 70 mM of monosodium phosphate aqueous solution at pH 2.5. Field‐amplified sample injection was used as preconcentration strategy to improve the sensitivity. We studied various parameters that affect this stacking strategy, in particular, the sample solvent and its pH, the presence or absence of a low conductivity solvent plug introduced before the sample injection, the nature and volume of this plug, and the voltage and time of the electrokinetic injection of the sample. The optimum conditions were achieved by injecting a plug of isopropanol:H₂O 50/50 at 50 mbar for 5 s prior to the electrokinetic injection of the sample prepared in an aqueous solution of HCl 10^?6 M. The sensitivity enhancement factors were from 562 to 601 in terms of peak area and from 444 to 472 in terms of peak height. The method was validated by analyzing spiked urine samples, obtaining a linear range of 25 to 1000 ng/mL and limits of detection ranging from 15 to 45 ng/mL.     

Dispersive liquid‐liquid microextraction coupled with pressure‐assisted electrokinetic injection for simultaneous enrichment of seven phenolic compounds in water samples followed by determination using capillary electrophoresis

Offline dispersive liquid‐liquid microextraction combined with online pressure‐assisted electrokinetic injection was developed to simultaneously enrich seven phenolic compounds in water samples, followed by determination using capillary electrophoresis, namely phenol, 4‐chlorophenol, pentachlorophenol, 2,4,6‐trichlorophenol, 2,4‐dichlorophenol, 2‐chlorophenol, and 2,6‐dichlorophenol. Several parameters affecting separation performance of capillary electrophoresis and the enrichment efficiency of pressure‐assisted electrokinetic injection and dispersive liquid‐liquid microextraction were systematically investigated. Under the optimal conditions, seven phenolic compounds were completely separated within 14 min and good enrichment factors were obtained of 61, 236, 3705, 3288, 920, 86, and 1807 for phenol, 4‐chlorophenol, pentachlorophenol, 2,4,6‐trichlorophenol, 2,4‐dichlorophenol, 2‐chlorophenol, and 2,6‐dichlorophenol, respectively. Good linearity was attained in the range of 0.1–200 μg/L for 2,4‐dichlorophenol, 0.5–200 μg/L for 4‐chlorophenol, pentachlorophenol, 2,4,6‐trichlorophenol, 2‐chlorophenol, and 2,6‐dichlorophenol, as well as 1–200 μg/L for phenol, with correlation coefficients (r) over 0.9905. The limits of detection and quantification ranging from 0.03–0.28 and 0.07–0.94 μg/L were attained. This two step enrichment method was potentially applicable for the rapid and simultaneous determination of phenolic compounds in water samples.     

Donor–acceptor‐based poly(toluidine‐co‐chloroaniline)s: Synthesis and characterization

A series of poly(o‐/m‐toluidine‐co‐o‐/m‐chloroaniline) copolymers of different compositions were synthesized by an emulsion method with ammonium persulfate as the oxidant. The conductivity of the copolymers was two to five orders of magnitude higher than that of the homopolymers poly(o‐toluidine) and poly(m‐chloroaniline). Among the copolymers, the copolymer of o‐toluidine and m‐chloroaniline exhibited a maximum conductivity of 0.14 S cm^?1. The conductivity of these copolymers was also higher than that of poly(aniline‐co‐chloroaniline). The properties of the copolymers were greatly influenced by the positions of the substituents and the concentrations of the individual monomers in the feed. All the copolymers were completely soluble in polar solvents such as dimethyl sulfoxide and showed higher heat stability as the chloroaniline concentration increased. These effects could be interpreted in terms of extensive hydrogen bonding and interchain linking and, therefore, higher electron delocalization in these copolymers due to the presence of electron‐rich toluidine rings adjacent to electron‐deficient chloroaniline. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1579–1587, 2005     

ToF‐SIMS and computation analysis: Fragmentation mechanisms of polystyrene,polystyrene‐d5, and polypentafluorostyrene

We studied the time‐of‐flight secondary ion mass spectrometry fragmentation mechanisms of polystyrenes—phenyl‐fluorinated polystyrene (5FPS), phenyl‐deuterated polystyrene (5DPS), and hydrogenated polystyrene (PS). From the positive ion spectra of 5FPS, we identified some characteristic molecular ion structures with isomeric geometries such as benzylic, benzocyclobutene, benzocyclopentene, cyclopentane, and tropylium systems. These structures were evaluated by the B3LYP‐D/jun‐cc‐pVDZ computation method. The intensities of the C₇H₂F₅⁺ (m/z = 181), CyPent‐C₉H₃F₄⁺ (m/z = 187), CyPent‐C₉H₄F₅⁺ (m/z = 207), and CyPent‐C₉H₂F₅⁺ (m/z = 205) ions were enhanced by resonance stabilization. The positive fluorinated ions from 5FPS tended to rearrange and produce fewer fluorine‐containing molecular ions through the loss of F (m/z = 19), CF (m/z = 31), and CF₂ (m/z = 50) ion fragments. Consequently, the fluorine‐containing polycyclic aromatic ions had much lower intensities than their hydrocarbon counterparts. We propose the fragmentation mechanisms for the formation of C₅H₅⁺, C₆H₅⁺, and C₇H₇⁺ ion fragments, substantiated with detailed analyses of the negative ion spectra. These ions were created through elimination of a pentafluoro‐phenyl anion (C₆F₅⁻) and H⁺, followed by a 1‐electron‐transfer process and then cyclization of the newly generated polyene with carbon‐carbon bond formation. The pendant groups with elements of different electronegativities exerted strong influences on the intensities and fragmentation processes of their corresponding ions.     

Microwave‐Assisted Synthesis and Antituberculosis Screening of Some 4‐((3‐(Trifluoromethyl)‐5,6‐dihydro‐[1,2,4]triazolo[4,3‐a]pyrazin‐7(8H)‐l)methyl)benzenamine Hybrids

In the present investigation, a series of 4‐((3‐(trifluoromethyl)‐5,6‐dihydro‐[1,2,4]triazolo[4,3‐a]pyrazin‐7(8H)‐yl)methyl)benzenamine analogs 6a–o were synthesized and characterized by IR, NMR (¹H and ¹³C), and mass spectra. All newly synthesized compounds 6a–o were prepared under conventional and microwave irradiation methods. These compounds obtained in higher yields and in shorter reaction times in the microwave irradiation method when compared with the conventional method. Synthesized compounds 6a–o were inspected for their in vitro antitubercular activity against Mycobacterium tuberculosis H₃₇Ra using an established XTT reduction menadione assay. Among the screened compounds, 6i (IC₅₀: 1.82 μg/mL), 6j (IC₅₀: 1.02 μg/mL), and 6k (IC₅₀: 1.59 μg/mL) showed excellent activity. Furthermore, compound 6i showed MIC₉₀ value of 16.02 μg/mL. In summary, the results indicate the identification of some novel, selective, and specific inhibitors against M. tuberculosis that can be explored further for the potential antitubercular drug.     

Solid‐phase microextraction based on an agarose‐chitosan‐multiwalled carbon nanotube composite film combined with HPLC–UV for the determination of nonsteroidal anti‐inflammatory drugs in aqueous samples

We describe the preparation, characterization, and application of a composite film adsorbent based on blended agarose‐chitosan‐multiwalled carbon nanotubes for the preconcentration of selected nonsteroidal anti‐inflammatory drugs in aqueous samples before determination by high performance liquid chromatography with ultraviolet detection. The composite film showed a high surface area (4.0258 m²/g) and strong hydrogen bonding between the multiwalled carbon nanotubes and agarose/chitosan matrix, which prevent adsorbent deactivation and ensure long‐term stability. Several parameters, such as sample pH, addition of salt, extraction time, desorption solvent, and concentration of multiwalled carbon nanotubes in the composite film were optimized using a one‐factor‐at‐time approach. The optimum extraction conditions obtained were as follows: isopropanol as conditioning solvent, 10 mL of sample solution at pH 2, extraction time of 30 min, stirring speed of 600 rpm, 100 μL of isopropanol as desorption solvent, desorption time of 5 min under ultrasonication, and 0.4% w/v of composite film. Under the optimized conditions, the calibration curve showed good linearity in the range of 1–500 ng/mL (r² = 0.997–0.999), and good limits of detection (0.89–8.05 ng/mL) were obtained with good relative standard deviations of < 4.59% (n = 3) for the determination of naproxen, diclofenac sodium salt, and mefenamic acid drugs.     

Magnetic micro‐solid‐phase extraction based on magnetite‐MCM‐41 with gas chromatography–mass spectrometry for the determination of antidepressant drugs in biological fluids

A new facile magnetic micro‐solid‐phase extraction coupled to gas chromatography and mass spectrometry detection was developed for the extraction and determination of selected antidepressant drugs in biological fluids using magnetite‐MCM‐41 as adsorbent. The synthesized sorbent was characterized by several spectroscopic techniques. The maximum extraction efficiency for extraction of 500 μg/L antidepressant drugs from aqueous solution was obtained with 15 mg of magnetite‐MCM‐41 at pH 12. The analyte was desorbed using 100 μL of acetonitrile prior to gas chromatography determination. This method was rapid in which the adsorption procedure was completed in 60 s. Under the optimized conditions using 15 mL of antidepressant drugs sample, the calibration curve showed good linearity in the range of 0.05–500 μg/L (r ² = 0.996–0.999). Good limits of detection (0.008–0.010 μg/L) were obtained for the analytes with good relative standard deviations of <8.0% (n  = 5) for the determination of 0.1, 5.0, and 500.0 μg/L of antidepressant drugs. This method was successfully applied to the determination of amitriptyline and chlorpromazine in plasma and urine samples. The recoveries of spiked plasma and urine samples were in the range of 86.1–115.4%. Results indicate that magnetite micro‐solid‐phase extraction with gas chromatography and mass spectrometry is a convenient, fast, and economical method for the extraction and determination of amitriptyline and chlorpromazine in biological samples.     

Photochromism and decolorization controlled by auxiliary ligands of complexes derived from 1‐methyl‐4,4′‐bipyridinium cation

Three 1‐methyl‐4,4′‐bipyridinium (MQ⁺)‐based complexes, {[Cd(MQ)(p‐BDC)Br]?H₂O}_n ( 1 ), {[Cd(MQ)(m‐BDC)(H₂O)Br]?3H₂O}_n ( 2 ) and Cu(MQ)Br₂ ( 3 ) (p‐H₂BDC = 1,4‐benzenedicarboxylic acid, m‐H₂BDC = 1,3‐benzenedicarboxylic acid), have been synthesized and structurally characterized. Compounds 1 and 2 are one‐dimensional coordination polymers constituted of one coordinated MQ⁺ cation, one coordinated Br^? ion and chains of Cd²⁺ ions connected by deprotonated BDC^2? units, which both have photochromism but different decolorization behaviors. The structures and photoresponsive behaviors controlled by auxiliary ligands have been explored. Compound 3 is constituted of one Cu⁺ center, one MQ⁺ ligand and two coordinated Br^? ions in a ‘V’ configuration, exhibiting no photochromism.     

Stacking Structure of Confined 1‐Butanol in SBA‐15 Investigated by Solid‐State NMR Spectroscopy

Understanding the complex thermodynamic behavior of confined amphiphilic molecules in biological or mesoporous hosts requires detailed knowledge of the stacking structures. Here, we present detailed solid‐state NMR spectroscopic investigations on 1‐butanol molecules confined in the hydrophilic mesoporous SBA‐15 host. A range of NMR spectroscopic measurements comprising of ¹H spin–lattice (T₁), spin–spin (T₂) relaxation, ¹³C cross‐polarization (CP), and ¹H,¹H two‐dimensional nuclear Overhauser enhancement spectroscopy (¹H,¹H 2D NOESY) with the magic angle spinning (MAS) technique as well as static wide‐line ²H NMR spectra have been used to investigate the dynamics and to observe the stacking structure of confined 1‐butanol in SBA‐15. The results suggest that not only the molecular reorientation but also the exchange motions of confined molecules of 1‐butanol are extremely restricted in the confined space of the SBA‐15 pores. The dynamics of the confined molecules of 1‐butanol imply that the ¹H,¹H 2D NOESY should be an appropriate technique to observe the stacking structure of confined amphiphilc molecules. This study is the first to observe that a significant part of confined 1‐butanol molecules are orientated as tilted bilayered structures on the surface of the host SBA‐15 pores in a time‐average state by solid‐state NMR spectroscopy with the ¹H,¹H 2D NOESY technique.     

Sodiation‐based in‐source collision for profiling of pyranocoumarins in Radix Peucedani (Qianhu): utility of sodium adducts' stability with in‐source collision

Full scan mode of liquid chromatography‐mass spectrometry equipped with an electrospray ionization source offers a chance on global detection of complicated components; however, the scan mode carries significant challenges in rapidly capturing information of analysts. Sodiation‐based in‐source collision was proposed here, as a technique for rapid detecting untargeted analytes in full scan analysis, which was based on the stability of sodium adducts and the nonselectivity of in‐source collision. Then the technique was applied to profile of angular‐type pyranocoumarins (APs) in Radix Peucedani, with full scan analysis performed at two specific in‐source collision energy: a high energy 50 V that is tolerated by the sodium adducts of APs, and a low energy 10 V, at which abundant adducts were offered. The spectra list of two average mass spectra was exported, and stable ions were selected based on the intensity ratio of standards at the two collision energy. Then 27 plausible [M + Na]⁺ m/z values of APs were acquired after filtering the fragment ion and isotope ions and validating with [M + NH₄]⁺. Eighty‐two APs finally were tentatively identified based on their accurate spectral data of MSⁿ, fragmentation rules, and elution order regardless of their absolute configuration, which included 25 reported APs from Peucedanum praeruptorum Dunn. The technique provided a novel application of sodium adduct in qualitative analysis. And it was valuable for rapidly capturing information of analytes in full scan analysis, not only for APs but also for other compounds that could form sodium adducts. Copyright © 2017 John Wiley & Sons, Ltd.