Xiangsheng Zhao

Gas chromatography with flame photometric detection of 31 organophosphorus pesticide residues in Alpinia oxyphylla dried fruits.

A simple, rapid and effective gas chromatography-flame photometric detection method was established for simultaneous multi-component determination of 31 organophosphorus pesticides (OPPs) residues in Alpinia oxyphylla, which is widely consumed as a traditional medicine and food in China. Sample preparation was completed in a single step without any clean-up procedure. All pesticides expressed good linear relationships between 0.004 and 1.0 μg/mL with correlation coefficients higher than 0.9973. The method gave satisfactory recoveries for most pesticides. The limits of detection varied from 1 to 10 ng/mL, and the limits of quantification (LOQs) were between 4 and 30 ng/mL. The proposed method was successfully applied to 55 commercial samples purchased from five different areas. Five pesticide residues were detected in four (7.27%) samples. The positive samples were confirmed by gas chromatography with tandem mass spectrometry (GC-MS/MS).

GC-FID coupled with chemometrics for quantitative and chemical fingerprinting analysis of Alpinia oxyphylla oil

Analytical methods for quantitative analysis and chemical fingerprinting of volatile oils from Alpinia oxyphylla were established. The volatile oils were prepared by hydrodistillation, and the yields were between 0.82% and 1.33%. The developed gas chromatography-flame ionization detection (GC-FID) method showed good specificity, linearity, reproducibility, stability and recovery, and could be used satisfactorily for quantitative analysis. The results showed that the volatile oils contained 2.31-77.30 μL/mL p-cymene and 12.38-99.34 mg/mL nootkatone. A GC-FID fingerprinting method was established, and the profiles were analyzed using chemometrics. GC-MS was used to identify the principal compounds in the GC-FID profiles. The profiles of almost all the samples were consistent and stable. The harvesting time and source were major factors that affected the profile, while the volatile oil yield and the nootkatone content had minor secondary effects.

A multiresidue method for simultaneous determination of 44 organophosphorous pesticides in Pogostemon cablin and related products using modified QuEChERS sample preparation procedure and GC–FPD

In this study, a modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method coupled with gas chromatography with flame photometric detection (GC-FPD) was developed for the determination of 44 organophosphorous pesticide (OPP) residues in 44 batches of Pogostemon cablin and its related products for the first time. The QuEChERS extraction conditions were optimized, and the matrix effect that may influence recoveries was evaluated and minimized by matrix-matched calibration curves. Under the optimized conditions, the calibration curves for all OPPs showed good linearities in the concentration range of 0.04-1.5 μg mL(-1) with correlation coefficients better than 0.9909. The limits of detection were in the range of 0.004-0.02 μg mL(-1) and quantification were 0.01-0.04 μg mL(-1), below the regulatory maximum residue limits suggested. Mean recoveries ranged between 76.62 and 113.7% (99.34% on average), and relative standard deviation was 3.71% on average. The validated method was applied on 44 real samples including P. cablin, and P. cablin oil and powder. Two (4.5%) samples were found to be contaminated by chlorpyrifos with levels below the legal limits, which were successfully confirmed by gas chromatography-mass spectrometry (GC-MS). Based on the results, the developed method was proved to be simple, fast, accurate, low cost and environmentally friendly and can be successfully applied in the determination of targeted OPP residues in P. cablin and its related products. Moreover, it also attaches great importance to pesticide monitoring programs in food, soil and air in the future.

Multi-elements determination in medical and edible Alpinia oxyphylla and Morinda officinalis and their decoctions by ICP-MS

Contents of twenty elements (Mg, K, Ca, Na, Fe, Al, Zn, Ba, Mn, Cu, Mo, Cr, Ni, As, Se, Cd, Hg, Tl, Pb and V) in two medical and edible plant species, Alpinia oxyphylla and Morinda officinalis were simultaneously determined by inductively coupled plasma-mass spectrometry (ICP-MS) method after microwave digestion with HNO3-H2O2 (6:1, v/v) as the digestion solvent. Certified standard reference material Poplar leaf was used to assess the accuracy of the method. The greatest contents of Mg, K, Ca, Al, Fe and Na were found in dried Alpinia oxyphylla and Morinda officinalis samples. The contents of five heavy metals including Pb, Cd, As, Hg and Cu in Alpinia oxyphylla did not exceed the limits. The contents of Pb in 76.67% samples and Cd in two batches of Morinda officinalis samples exceeded the limits set by Chinese Pharmacopeia. The contents of the selected elements in different parts (leaves, stems, roots and fruits) of Alpinia oxyphylla varied considerably. The highest concentrations of Mg, Ca, Mn and Se were found in the leaves of Alpinia oxyphylla, at the same time, while, the contents of 9 elements including Cd, Cr, Cu, As, Pb in the roots were the highest. The transfer ratios of selected elements from both species of herbs into their decoctions were reduced. Especially for the heavy metals, the transfer ratios were below 30% except As (79.73%) in Morinda officinalis. The results showed that decoction of the samples may reduce the intake of heavy metals.

Analysis of six bioactive components in Semen Ziziphi Spinosae by UPLC-ELSD and UPLC-Q/TOF-MS

A simple and sensitive method was first developed for the simultaneous determination of six bioactive compounds in Semen Ziziphi Spinosae, which is commonly used in traditional Chinese medicines, by ultra-performance liquid chromatography coupled with an evaporative light scattering detector (UPLC-ELSD). Furthermore, the main compounds were identified using UPLC coupled with electrospray ionization and time-of-flight mass spectrometry (ESI-Q/TOF-MS). The separation of the compounds of interest was performed on a BEH C18 column with acetonitrile and water (0.1% aqueous formic acid) as the mobile phase. Six analytes (spinosin, jujuboside A, jujuboside D, jujuboside B, jujuboside B1, betulinic acid) demonstrated good linearity (r2 > 0.9984) over a relatively wide concentration range. The method revealed high average recovery (range, 94.36–99.49%) and good precision with inter- and intra-day variations with RSD less than 4.72%. The limits of detection (LOD) ranged from 10.4–31.2 ng, while the limits of quantification (LOQ) were defined in the range of 21.9–84.0 ng. The validated method was successfully applied to quantitatively analyze 28 samples of different places from China. The results show there are great variations among the contents of the six ingredients. These results demonstrate that this approach has the potential for the quality control of Semen Ziziphi Spinosae.

Enhancement effect of essential oils from the fruits and leaves of Alpinia oxyphylla on skin permeation and deposition of indomethacin

Essential oils from plants are gaining increasing attention as potential chemical penetration enhancers. This study aimed to investigate the enhancement effect of essential oils from the fruits and leaves of Alpinia oxyphylla on skin permeation and deposition of indomethacin. In vitro permeation experiments were performed in Franz-type cells through rat skin, and the amount of drug passing through into the receptor phase was analyzed by ultra performance liquid chromatography-photodiode array (UPLC-PDA). Ultra fast liquid chromatography coupled with tandem mass spectrometry (UFLC-MS/MS) was used to analyze the plasma drug concentration of indomethacin to examine the enhancement effect of essential oils in an in vivo rat model of drug delivery. Both oils demonstrated a significant enhancement effect on drug delivery and skin deposition (p < 0.05). Particularly, at 3% concentration, enhancement ratios of fruit oil and leaf oil were 10.16 and 4.61, respectively, which were both significantly higher than that of the commonly used enhancer, Azone (2.04). Major constituents of both oils were identified by gas chromatography-mass spectrometry (GC-MS). It may be deduced that higher content hydrocarbon terpenes in the fruit oil contribute to the increased enhancement effect relative to leaf oil. The skin irritation test indicated that both oils at certain concentrations (1%, 3%, and 5%) did not cause obvious erythema or edema in rabbits. Considering their enhanced drug permeation and low skin irritation, essential oils from Alpinia oxyphylla could be novel penetration enhancers and have promising applications in transdermal drug delivery and cosmetics.

Simultaneous analysis of multiple mycotoxins in Alpinia oxyphylla by UPLC-MS/MS

In this study, a reliable and fast method for the simultaneous quantitation of 11 mycotoxins in Alpinia oxyphylla was developed using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLCMS/ MS). Three different extraction procedures (solid-liquid extraction, solid-phase extraction and modified QuEChERS) were evaluated. Solid-liquid extraction was fast and easy, and also provided the best recovery rate for all mycotoxins, compared to the other extraction procedures. Some crucial factors, including extraction solvent, time and temperature, were carefully optimised. Significant matrix effects were offset using matrix-matched calibration. Under these optimised conditions, our detection approach showed a good, linear dynamic range with correlation coefficients (R2) above 0.9958. The limit of quantification ranged from 0.1 to 20 μg/kg. Accuracy was determined in a selected matrix using blank samples spiked with the target mycotoxins at three different concentration levels. The rec...

Solid-phase extraction using molecularly imprinted polymer for determination of ochratoxin A in human urine

A rapid, selective and reliable sample preparation technique employing solid-phase extraction (SPE) based on molecularly imprinted polymer (MIP) for the determination of ochratoxin A (OTA) in human urine was described. After sample adjustment to pH 2.5 with 0.1 M HCl, the urine sample was loaded onto the MIP-SPE column, and after a wash step, OTA was eluted for measurement by ultra-high performance liquid chromatography coupled with fluorescence detection. Key parameters which affected the MIP-SPE extraction efficiency were optimized as was the detection method. Under the optimised conditions, the limits of detection and quantification for OTA in urine were 0.2 ng/ml and 0.6 ng/ml, respectively. The recoveries for OTA in urine, spiked at the 0.6, 6.0 and 60 ng/ml levels, ranged from 92.0 to 98.9%. Sixty urine samples were analysed, of which four were found to contain OTA at concentrations ranging from 0.022 to 0.083 ng/ml; the positive results were confirmed by liquid chromatography coupled with tandem ma...

Simultaneous determination of three alkaloids in Huperzia serrata by UPLC-PDA and UPLC-Q/TOF-MS

In the current study, a reliable method has been developed and validated for quantification of three alkaloids (Huperzine A, Huperzine B and Huperzine C) from Huperzia serrata based on ultraperformance liquid chromatography (UPLC) with a photodiode array detector (PDA) and confirmed by tandem quadrupole time-of-flight mass spectrometry (Q/TOF-MS). Separation was performed on a Waters BEH shield RP 18 column with gradient elution. The detection wavelength was set at 310 nm. The evaluation of the method showed good linearity, repeatability, accuracy and precision. The limits of quantification varied from 0.11 to 0.4 μg g−1 depending on the analytes. The proposed method was successfully applied to determine the three alkaloids in the samples of 18 batches of different origins from China. The results indicated that significant variation in the amount of quantitative ingredients was observed in different parts of samples from different sources. The contents of Huperzine A and Huperzine B in Hainan samples were significantly lower than those in samples from other areas. The method developed could be helpful for the quality control of Huperzia serrata. The present study can provide necessary information for the rational utilization of Huperzia serrata resources in Hainan province.

Simultaneous Analysis of Iridoid Glycosides and Anthraquinones in Morinda officinalis Using UPLC-QqQ-MS/MS and UPLC-Q/TOF-MSE

Morinda officinalis is an important herbal medicine and functional food, and its main constituents include anthraquinone and iridoid glycosides. Quantification of the main compounds is a necessary step to understand the quality and therapeutic properties of M. officinalis, but this has not yet been performed based on liquid chromatography/tandem mass spectrometry (LC-MS/MS). Analytes were extracted from M. officinalis by reflux method. Ultrahigh-performance liquid chromatography coupled with a triple quadrupole mass spectrometry (UPLC-QqQ-MS) using multiple reaction monitoring (MRM) mode was applied for quantification. Fragmentation pathways of deacetyl asperulosidic acid and rubiadin were investigated based on UPLC with quadrupole time-of-flight tandem mass spectrometry (Q/TOF-MS) in the MSE centroid mode. The method showed a good linearity over a wide concentration range (R2 ≥ 0.9930). The limits of quantification of six compounds ranged from 2.6 to 27.57 ng/mL. The intra- and inter-day precisions of the investigated components exhibited an RSD within 4.5% with mean recovery rates of 95.32–99.86%. Contents of selected compounds in M. officinalis varied significantly depending on region. The fragmentation pathway of deacetyl asperulosidic and rubiadin was proposed. A selective and sensitive method was developed for determining six target compounds in M. officinalis by UPLC-MS/MS. Furthermore, the proposed method will be helpful for quality control and identification main compounds of M. officinalis.