Integrating UPLC-QTOF-MS/MS and UPLC-DAD to evaluate the influence of sulfur-fumigated Paeoniae Radix Alba on the overall quality of three Si-Wu-Tang formulations.

INTRODUCTION: Sulfur-fumigation of Paeoniae Radix Alba (PRA) could induce the chemical transformation of its bioactive component paeoniflorin into a sulfur-containing derivative paeoniflorin sulfite, and thus alter the quality, bioactivities, pharmacokinetics, and toxicities of PRA. However, how sulfur-fumigated PRA (S-PRA) affects the quality of PRA-containing complex preparations has not been intensively evaluated. OBJECTIVES: We intend to evaluate the influence of S-PRA on the overall quality of three kinds of Si-Wu-Tang (SWT) formulations, i.e., decoction (SWT-D), granule (SWT-G), and mixture (SWT-M). MATERIAL AND METHODS: An UPLC-DAD multi-components quantification method was used to compare the transfer rates of paeoniflorin sulfite and other 10 bioactive components between S-PRA-containing and NS-PRA-containing SWT formulations. An UPLC-QTOF-MS/MS-based target metabolomics approach was applied to explore the differential sulfur-containing derivatives in S-PRA-containing SWT formulations. RESULTS: The transfer rates of paeoniflorin sulfite in three S-PRA-containing SWT formulations were all higher than 100%. Moreover, S-PRA also increased the transfer rate of 5-hydroxymethylfurfural, 1,2,3,4,6-O-pentagalloylglucose, whereas decreased that of paeoniflorin, albiflorin, and ferulic acid in three SWT formulations. Six pinane monoterpene glucoside sulfites originally identified in S-PRA, were also detectable in three S-PRA-containing SWT formulations. In addition, seven phenolic acid sulfites including (3Z)-6-sulfite-ligustilide, (3E)-6-sulfite-ligustilide, 6,8-disulfite-ligustilide, ferulic acid sulfite, neochlorogenic acid sulfite, chlorogenic acid sulfite, and angelicide sulfite (or isomer) were newly identified in these three S-PRA-containing formulations. CONCLUSION: S-PRA could differentially affect the transfer rate of paeoniflorin sulfite and other bioactive components during the preparation of three SWT formulations and subsequently the overall quality thereof.

Preparation of surface molecular imprinting fluorescent sensor based on magnetic porous silica for sensitive and selective determination of catechol.

A magnetic fluorescent molecularly imprinted sensor was successfully prepared and implemented to determine catechol (CT). Fe3O4 nanoparticles were synthesized by the solvothermal technique and mesoporous Fe3O4@SiO2@mSiO2 imprinted carriers were prepared by coating nonporous and mesoporous SiO2 shells on the surface of the Fe3O4 subsequently. The magnetic surface molecularly imprinted fluorescent sensor was created after the magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane to introduce double bonds on the surface of the carries and the polymerization was carried out in the presence of CT and fluorescent monomers. The magnetic mesoporous carriers were modified with γ-methacryloxyl propyl trimethoxy silane and double bonds were introduced on the surface of the carriers. After CT binding with the molecularly imprinted polymers (MIPs), the fluorescent intensity of the molecularly imprinted polymers (Ex = 400 nm, Em = 523 nm) increased significantly. The fluorescent intensity ratio (F/F0) of the sensor demonstrated a favorable linear correlation with the concentration of CT between 5 and 50 µM with a detection limit of 0.025 µM. Furthermore, the sensor was successfully applied to determine CT in actual samples with recoveries of 96.4-105% and relative standard deviations were lower than 3.5%. The results indicated that the research of our present work provided an efficient approach for swiftly and accurately determining organic pollutant in water.

Preparation of molecularly imprinted ratiometric fluorescence sensor for visual detection of tetrabromobisphenol A in water samples.

A sensitive molecularly imprinted ratiometric fluorescence sensor was constructed for the first time to visually detect tetrabromobisphenol A (TBBPA). The blue fluorescent carbon quantum dots (CQDs) were coated with SiO2 through the reverse microemulsion method to obtain a stable internal reference signal CQDs@SiO2. The ratiometric fluorescence sensor was finally prepared using red fluorescent CdTe QDs as the response signal in the presence of CQDs@SiO2. When the molecularly imprinted polymers were combined with TBBPA, the fluorescence of CdTe QDs (Ex = 365 nm, Em = 665 nm) was rapidly quenched, while that of CQDs (Ex = 365 nm, Em = 441 nm) remained stable, resulting in a noticeable fluorescence color change. Moreover, the fluorescence intensity ratio (I665/I441)0/(I665/I441) of the sensor showed a linear response to TBBPA in the concentration range 0.1 to 10 µM with a low detection limit of 3.8 nM. The prepared sensor was successfully applied to detect TBBPA in water samples. The recoveries were in the range 98.2-103%, with relative standard deviations lower than 2.5%. Furthermore, a fluorescent test strip for visual monitoring of TBBPA was constructed to streamline the procedure. The excellent results demonstrate that the prepared test strip has a broad prospect for the offline detection of pollutants.

Quality consistency evaluation of commercial Prunellae Spica by integrating determination of secondary metabolites and saccharides.

INTRODUCTION: Prunellae Spica (PS) is a commonly used medicinal herb in China. Secondary metabolites and saccharides are major bioactive components of PS. However, holistic quality consistency of commercial PS is ambiguous due to lack of comprehensive evaluation methods and reliable quality control markers. OBJECTIVES: Integrating multiple chromatographic and chemometric methods to comprehensively evaluate the holistic quality of PS. MATERIAL AND METHODS: Ultrahigh-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-TQ-MS/MS) was applied to quantify 12 secondary metabolites of PS. High-performance liquid chromatography coupled with photodiode array/evaporative light scattering detection (HPLC-PDA/ELSD) and high-performance gel permeation chromatography (HPGPC) methods were used to characterise the saccharides. Multivariate statistical analysis was adopted to evaluate the quality consistency of commercial PS and explore the potential quality control markers. RESULTS: The contents of secondary metabolites and saccharides were significantly different among commercial PS. All samples could be classified into three groups with ferulic acid, protocatechualdehyde, gallic acid, ursolic acid/oleanolic acid, sucrose, p-coumaric acid, chlorogenic acid as the major contributing components responsible for the difference. The content of rosmarinic acid was correlated with that of betulinic acid, hyperposide, chlorogenic acid, rutin, caffeic acid, p-coumaric acid and glucose, whereas polysaccharides, ferulic acid, protocatechualdehyde and ursolic acid/oleanolic acid, quercetin, sucrose and majority monosaccharides were not. CONCLUSION: The holistic quality of commercial PS was inconsistent. Together with rosmarinic acid, ferulic acid, protocatechualdehyde, ursolic acid/oleanolic acid, polysaccharides and sucrose might be recommended as potential quality control markers for the holistic quality control of PS.

Effect of air and exhaust gas dilutions on ultra-fine particulate emissions in different combustion modes.

The effect of air and exhaust dilution ratios on the characteristics of ultra-fine particulate matter (PM) and combustion process in different combustion modes at low loads were investigated based on experimental and numerical simulation in this study. The combustion modes included partially premixed compression ignition (PPCI), diffusion combustion (DC), and modulated kinetics combustion (MKC). The air and exhaust gas dilution ratio varied from 0 % to 40 % and 0 % to 55 % respectively. Additionally, the effect of dilutions and combustion modes on PM characteristics is precisely analyzed by computational fluid dynamics. The NOx and Soot emission are reduced in PPCI and DC mode of combustion with the increase of air and exhaust gas dilution rate. However, NOx emission is decreases while Soot is increases in MKC mode. The concentration of particulate number increases in case of both PPCI and DC mode and achieved highest value as 3.3 × 107 and 1.4 × 107 N/cc respectively. Although, concentration of particulate number (PN) in MKC mode first starts climbing and after attaining the highest level of 1.3 × 107 N/cc it falls down. PN concentration in PPCI, MKC, and DC modes decreases as the exhaust gas dilution rate increases. The study of nuclear and accumulate mode of PM was performed separately where the diameter of particles is <1000 nm. Under variable air and exhaust gas dilution ratios, the value of PN is always lies between 40 and 90 % in the nuclear mode PM domain for PPCI and DC modes while for MKC mode, the proportion of PN fall under 13-57 % at exhaust gas ratio above 30 %. The proportion of nuclear mode particulate mass in PPCI mode is >10 % while its values is <1 % for DC and MKC modes.