High Performance Liquid Chromatography-triple Quadrupole Research Articles

Simultaneous Quantification of Four Compounds in Rat Plasma by HPLC-MS/MS and Its Application to Pharmacokinetic Study after Oral Administration of Pomegranate Flowers.

Pomegranate flowers (PFs) were reported to possess various biological activities such as antidiabetic, anti-inflammatory and hepatoprotective activities, and using to treat diabetes. Although chemical constituents and pharmacological activities of PFs have been studied, unfortunately, there was no report on the pharmacokinetic profile of PFs in vivo. In this study, a selective high-performance liquid chromatography triple quadrupole tandem mass spectrometry (HPLC-QQQ-MS/MS) method was developed and validated for simultaneous quantification of four compounds (corilagin, ellagic acid, gallic acid and brevifolincarboxylic acid) in rat plasma after oral administration of PFs. The good linearity concentration ranges for the four analytes were from 2.5 to 3000ng/mL with coefficient value R2 > 0.99 in calibration curves. The intra- and inter-day accuracy of the four analytes was in the range of 85.33-102.50%, with relative standard deviation (RSD) of <14.81%. The stability results showed that accuracy of the four analytes was in the range of 81.88-104.74%, with RSD of <14.86%. The validation method was successfully applied to pharmacokinetic profiles of the four analytes in rats after oral administration of PFs extract. This pharmacokinetic study can provide better understanding to clarify in vivo mechanisms of PFs and may facilitate its further development as therapeutic agent.

Variations in phenolic acids and antioxidant activity of navel orange at different growth stages

Ripe navel orange has abundant amounts of phenolic compounds. Few studies monitored changes in these compounds during ripening. In this study, the effects of navel orange maturation on dynamic changes in antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC) and phenolic acids were investigated. Five growth stages of navel orange were studied, and nine phenolic acids were detected via high performance liquid chromatography–triple quadrupole mass spectrometry (HPLC–QQQ–MS). Results showed that antioxidant activity, TFC and TPC decreased gradually with fruit ripening. The concentrations of most phenolic acids also declined during fruit maturation, except for free fractions of sinapic acid and bound fractions of ferulic and caffeic acids. Ferulic acid was the most dominant of all phenolic acids at all growth stages. Partial least-squares showed significant differences among fruits of different maturities. A significant correlation between antioxidant capacity, TPC, TFC and some phenolic acids was found.

Determination of caffeine content in Ginkgo Folium by ultra high performance liquid chromatography-triple quadrupole mass spectrometry

In this experiment, an ultra-high performance liquid chromatographytandem triple quadrupole mass spectrometry was established for the determination of caffeine in commercially available Ginkgo Folium. The samples were extracted by ultrasonic method with methanol, and separated on Waters CORTECS T3 column(2.1 mm×100 mm, 2.7 μm), with mobile phase of 0.1% formic acid solution-0.1% formic acid acetonitrile solution for gradient elution, at flow rate of 0.3 mL·min~(-1); column temperature of 30 ℃, and injection volume of 2 μL. Mass spectrometry was conducted at ESI~+ multiple reaction monitoring(MRM) mode; quantitative analysis was conducted with external standard method. The results showed that in the range of 0.099 6-9.96 ng·mL~(-1), there was a good linear relationship between the mass concentration of caffeine and the peak area, R~2=0.999; the average recovery was 84.51%, with RSD of 6.2%. The results of precision, repeatability and stability showed that the RSD was 5.1%, 5.9%, 7.2%, respectively. The content range of caffeine in 10 batches of Ginkgo Folium was 1.52-60.86 μg·kg~(-1). In conclusion, this method is accurate, reliable and reproducible, which provides a reference for the safety study of Ginkgo Folium.

Determination of Polyphenols in Ilex kudingcha and Insect Tea (Leaves Altered by Animals) by Ultra-high-performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry (UHPLC-QqQ-MS) and Comparison of Their Anti-Aging Effects.

Ilex kudingcha C.J. Tseng tea and insect tea, as traditional Chinese teas, are favored for their original craftsmanship, unique flavor, and biological functionality. In this study, ultra high-performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-QqQ-MS) was used to analyze the bioactive components of the extracts of Ilex kudingcha and insect tea, and D-galactose-induced aging mice were used to compare the in vivo anti-aging effects of Ilex kudingcha and insect tea extracts. The results were remarkable, UHPLC-QqQ-MS analysis showed that ITP contains 29 ingredients, while IKDCP contains 26 ingredients. However, due to the large differences in the content of the main chemical components in IKDCP and ITP, the effects are equally different. At the same time, the in vivo research results suggesting that the anti-aging effects of IKDCP and ITP (500 mg/kg) include the regulation of viscera indices of major organs; improvement in liver, skin, and spleen tissue morphology; decreased production of inflammatory cytokines; up regulation of SOD, CAT, GSH, GSH-PX, and T-AOC and down regulation of NO and MDA levels in serum and liver tissue; reductions in the concentration of pro-inflammatory factors, and increases in the concentration of anti-inflammatory factor. RT-qPCR and western blot assay also showed that IKDCP and ITP affect anti-aging by regulating the gene and protein expression of GSH-PX, GSH1, SOD1, SOD2, and CAT. The overall results indicate that ITP is more effective in treating oxidative damage in aging mice induced by D-galactose. Thus, ITP appears to be an effective functional drink owing to its rich nutritional components and anti-aging activities.

A QuEChERS-HPLC-MS/MS Method with Matrix Matching Calibration Strategy for Determination of Imidacloprid and Its Metabolites in Procambarus clarkii (Crayfish) Tissues.

We developed a method for determination of imidacloprid and its metabolites 5-hydroxy imidacloprid, olefin imidacloprid, imidacloprid urea and 6-chloronicotinic acid in Procambarus clarkii (crayfish) tissues using quick, easy, cheap, effective, rugged, and safe (QuEChERS) and high-performance liquid chromatography-triple quadrupole mass spectrometry. Samples (plasma, cephalothorax, hepatopancrea, gill, intestine, and muscle) were extracted with acetonitrile containing 0.1% acetic acid and cleaned up using a neutral alumina column containing a primary secondary amine. The prepared samples were separated using reverse phase chromatography and scanned in the positive and negative ion multiple reaction-monitoring modes. Under the optimum experimental conditions, spiked recoveries for these compounds in P. clarkii samples ranged from 80.6 to 112.7% with relative standard deviations of 4.2 to 12.6%. The limits of detection were 0.02–0.5 μg·L−1, the limits of quantification were 0.05–2.0 μg·L−1 and the method of quantification was 0.05–2.0 μg·kg−1. The method is rapid, simple, sensitive and suitable for rapid determination and analysis of imidacloprid and its metabolites in P. clarkii tissues.

Terahertz Spectroscopy for Accurate Identification of Panax quinquefolium Basing on Nonconjugated 24(R)-Pseudoginsenoside F11.

Panax quinquefolium is a perennial herbaceous plant that contains many beneficial ginsenosides with diverse pharmacological effects. 24(R)-pseudoginsenoside F11 is specific to P. quinquefolium, a useful biomarker for distinguishing this species from other related plants. However, because of its nonconjugated property and the complexity of existing detection methods, this biomarker cannot be used as the identification standard. We herein present a stable 24(R)-pseudoginsenoside F11 fingerprint spectrum in the terahertz band, thereby proving that F11 can be detected and quantitatively analyzed via terahertz spectroscopy. We also analyzed the sample by high-performance liquid chromatography-triple quadrupole mass spectrometry. The difference between the normalized data for the two analytical methods was less than 5%. Furthermore, P. quinquefolium from different areas and other substances can be clearly distinguished based on these terahertz spectra with a standard principal component analysis. Our method is a fast, simple, and cost-effective approach for identifying and quantitatively analyzing P. quinquefolium.

Determination of carbendazim residues in Procambarus clarkii by high performance liquid chromatography-triple quadrupole mass spectrometry

A novel method based on high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-MS/MS) was established for the determination of carbendazim in Procambarus clarkii. The sample was extracted by ethyl acetate under alkaline conditions and centrifuged. The supernatant was concentrated by rotary evaporation, redissolved, and then enriched and purified on a mixed-mode cation exchange solid phase extraction column (MCX). A C18 column was used with acetonitrile and water as mobile phases in a gradient elution. Ionization was performed using an electrospray positive ion source (ESI+), and detection was achieved by MS/MS in multiple reaction monitoring (MRM) mode. The linearity for carbendazim was good in the range of 0.5-50.0 μg/L; the linear equation was y=0.19988x+0.01842; and the correlation coefficient (r2) was 0.9985. The limit of detection (LOD) and limit of quantification (LOQ) were 0.25 μg/kg and 0.50 μg/kg, respectively. At spiked levels of 0.5, 1.0, 5.0, and 50.0 μg/kg, the recoveries ranged from 83.9% to 105.5%, and the relative standard deviation ranged from 1.1% to 3.2%. This method is simple and effective for the determination of carbendazim residues in P. clarkii.

Determination of ibotenic acid and muscimol in plasma by liquid chromatography-triple quadrupole mass spectrometry with bimolecular dansylation

Ibotenic acid (IBA) is an amino acid and muscimol (MUS) is the decarboxyl derivative of IBA. They are mushroom neurotoxins with high polarity and low molecular weight. Only one transition (159–>113 for IBA and 115->98 for MUS) can be found when directly measured by high performance liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Therefore, the identification and quantification of trace amount of the toxins in biomaterial are difficult. A highly sensitive and accurate analytical method for IBA and MUS in plasma was developed by LC-MS/MS with the application of bimolecular dansylation and internal standard calibration. Acetonitrile was used for protein precipitation and for toxin extraction from plasma. The toxins and internal standards (L-tyrosine-13C9,15N for IBA and tyramine-d4 for MUS) were derivatized with dansyl chloride (DNSCl). The reaction conditions of the bimolecular dansylation were optimized and the fragmentation pathways of the derivatives in MS/MS were studied. Method validation was carried out according to the Bioanalytical Method Validation Guidance for Industry (FDA, USA, 2018). The limits of detection for IBA and MUS in plasma were 0.3 ng mL−1 and 0.1 ng mL−1, respectively. The linear ranges in plasma were 1–500 ng mL−1 and 1–200 ng mL−1 with the correlation coefficients of 0.998 and 0.999 for IBA and MUS, respectively. The recoveries at three spiked levels were 90.7–111.4% with relative standard deviations (RSDs) of 6.4–10.3% for IBA and the results were 85.1–94.2% with RSDs of 5.0–8.9% for MUS. The toxin levels in patients’ plasma samples under different poisoning degree were presented.

Peptide analysis of mammalian decomposition fluid in relation to the post-mortem interval

We report the results of a semi-quantitative peptide analysis of decomposition fluid under field-based conditions in the absence of a soil matrix. Sixteen domestic pig (Sus scrofa domesticus) cadavers were used to model human decomposition in trials conducted in the summer and winter months in Western Australia. Physical characteristics were recorded and targeted peptide components of decomposition fluid were analysed using high performance liquid chromatography-triple quadrupole mass spectrometry. Principal component analysis identified 29 peptides, originating from haemoglobin subunits alpha and beta, creatine kinase, beta-enolase and lactate dehydrogenase, that contributed to differences in the mean peak areas of samples collected during the early period of decomposition (days 6–12 and day 2 in winter and summer, respectively) and during the later period (days 24–34 and days 8–10 in winter and summer, respectively). Fold changes for 8 peptides between these periods were significantly different. Three peptides derived from haemoglobin subunit beta, one from beta-enolase and two from lactate dehydrogenase displayed consistent trends, in that a notable increase in mean peak area was followed by a marked decrease in both the summer and winter samples. When temperature was accounted for, these trends occurred at different time points in summer and winter, indicating that factors other than temperature had impacted the rate of degradation of the proteins involved. The single peptides derived from haemoglobin subunit alpha and creatine kinase displayed consistent increases in mean peak area for the summer samples, suggesting that temperature played the most significant role in their degradation. Further analyses revealed that 7 peptides (one originating from haemoglobin subunit alpha, three from haemoglobin subunit beta and three from lactate dehydrogenase) displayed consistent trends that could be correlated with total body score and with the early stages of decomposition. The consistent trends (mean peak area versus time) for peptides derived from several proteins during decomposition trials conducted under different temperature regimes further emphasised the potential of peptide analysis in time since death estimation.

Effects of gut microbiota on five absorbed components of Berberis kansuensis in rat serum by HPLC-QqQ-MS

To elucidate the absorption and metabolism of alkaloids in Berberis kansuensis in vivo, a high performance liquid chromatography-triple quadrupole mass spectrometry(HPLC-QqQ-MS) method was developed to qualitatively and quantitatively analyze the absorption components in rat serum in multiple-reaction monitoring mode. The mobile phase consisted of 0.1% formic acid and acetonitrile with a gradient elution mode. In addition, to investigate the effects of gut microbiota on five absorbed components of B. kansuensis in rat serum, diabetic rat and pseudo germ-free diabetic rat models were established, and partial least squares discriminant analysis and One-way ANOVA were used to study the content differences of five components among different groups. In this study, a HPLC-QqQ-MS method for quantitative analysis of five components in rat serum after oral administration of B. kansuensis was established for the first time. It was found that there were differences in the five constituents in rat serum between different groups. By comparing the normal group with the diabetic model group, we found that the absorption and metabolism capacities of berberine and magnoflorine were different under the health and pathological conditions. It was also found that the serum levels of berberine, magnoflorine and jatrorrhizine in pseudo germ-free diabetic rats were significantly lower than those in diabetic rats, indicating that gut microbiota plays an important role in the metabolism of alkaloids of B. kansuensis in vivo. These results provide a good reference for clarifying the active ingredients of B. kansuensis in the treatment of diabetes.

Determination of pendimethalin in water, sediment, and Procambarus clarkii by high performance liquid chromatography-triple quadrupole mass spectrometry.

We established a high-performance liquid chromatography-triple quadrupole mass spectrometry method for the analysis of pendimethalin residues in water, sediments, and Procambarus clarkii (Louisiana crayfish) tissues. Water samples were concentrated on a HLB solid-phase extraction column and eluted with dichloromethane and acetone (1:1). After drying under a stream of nitrogen gas, the sample volume was adjusted to 1 mL with the mobile phase solvent methanol/water/acetic acid (8:20:0.1). Pendimethalin was extracted with ethyl acetate containing 0.1% acetic acid, after rotary evaporation to dryness at 35 °C, the residue was dissolved in mobile phase solvent, purified by a neutral alumina column and graphitized carbon black powder (0.1 g). The mass characterization was conducted in positive ion mode, and the corresponding ions were detected in multi-reaction monitoring mode. The linear equations were y = 1 × 106x + 14275, at pendimethalin levels of 0.05-20 μg L-1 and y = 691029 × - 414368 for 20-200 μg L-1. The detection limits of pendimethalin in water, sediments, and P. clarkii tissues were 1.0 × 10-4μg L-1, 5.0 × 10-3μg kg -1and 5.0 × 10-3 μg kg -1, respectively. The spiked recoveries ranged from 81.6 to 106.3%, and the relative standard deviations ranged from 4.58 to 13.6% (n = 6). The method provided an efficient and low-cost extraction and purification procedure that enabled a sensitive determination of pendimethalin in water as well as complex matrices.

Stable isotope dilution assay for the accurate determination of tricaine in fish samples by HPLC-MS-MS.

Tricaine methanesulfonate is one of most commonly used anesthetics in fish during blood sampling, artificial propagation and long-distance transportation. In this study, an accurate method for the quantitative determination of tricaine in fish samples by a stable isotope dilution assay coupled with high-performance liquid chromatography-triple quadrupole mass spectrometry was developed. Tricaine-D5 was synthesized and used as an isotopically labeled internal standard for the determination of tricaine. The analytical performance of the method was validated for tricaine determination in marine fish and freshwater fish. The determination of tricaine was linear in the range of 2.0-200.0 μg L-1 . The limit of detection and limit of quantitation for fish muscle tissues were 1.0 and 4.0 μg kg-1 , respectively. Good recoveries were obtained in the range of 92.08-97.50%. The inter- and intra-assay relative standard deviations (RSD values) were investigated, and the values were 0.39-3.01 and 0.85-2.77%, respectively. The values of CCα and CCβ were 10.21-10.43 and 10.42-10.87 μg kg-1 , respectively. The clearance of MS-222 from grass carp was further studied using our method. The results demonstrate that MS-222 could be well absorbed and rapidly eliminated after bath administration.

Detection of New Quorum Sensing N-Acyl Homoserine Lactones From Aeromonas veronii.

Sturgeon is an important fresh water-culture fish in China. A problem with sturgeon is its high susceptibility to spoilage. Food spoilage is reported to be regulated by quorum sensing (QS). To identify the QS signals acetylated homoserine lactones (AHLs) in sturgeon and test whether QS plays a role in the spoilage of sturgeon, we investigated the specific spoilage organisms (SSOs) in vacuum packaged sturgeon stored at 4°C and the production of AHLs by sturgeon SSOs. 16S rDNA sequencing and spoilage capabilities analysis revealed that Aeromonas veronii LP-11, Citrobacter freundii LPJ-2, and Raoultella ornithinolytica LPC-3 were the SSOs in sturgeon. Among the three SSOs, only A. veronii LP-11 induced the QS biosensors Agrobacterium tumefaciens KYC55 and Chromobacterium violaceum CV026, suggesting that it produced AHLs. Analysis by thin layer chromatography, high-performance liquid chromatography-triple quadrupole tandem mass spectrometry, and high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC/qTOF-MS) identified that the AHLs produced by A. veronii were C6-SHL, C8-HSL, 3-oxo-C8-HSL, and 3-OH-C8-HSL. Our study revealed that QS system was probably involved in the regulation of sturgeon spoilage and for the first time reported the production of C8-HSL and 3-OH-C8-HSL by genus Aeromonas. As only HPLC/qTOF-MS effectively and accurately identified all the four AHLs produced by A. veronii LP-11, this study also showed that HPLC/qTOF-MS was the most efficient method for rapid analysis of AHLs in complex microbial sample. The study provides new insight into the microbiology of sturgeon spoilage which may be helpful for better sturgeon preservation.

Determination of pendimethalin residues in Procambarus clarkii by high performance liquid chromatography-triple quadrupole mass spectrometry

A novel method was developed for the determination of pendimethalin in Procambarus clarkii by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Samples were extracted with ethyl acetate containing 0.1%(v/v) acetic acid, and the extracts were dried at 35℃. The final extracts were redissolved with methanol-water (8:2, v/v) containing 0.1%(v/v) acetic acid and cleaned up by acidic alumina column and graphitized carbon black (GCB). The prepared samples were separated on a Symmetry C18 column (100 mm×2.1 mm, 3.5 μm) and characterized using a heated electrospray ionization (HESI) source in the positive ion multiple reaction monitoring mode. Under optimum experimental conditions, the standard curve was linear in the range of 1.0-20.0 μg/L with the correlation coefficient of 0.9960. The limit of detection was 0.5 μg/kg. The spiked recoveries of the pendimethalin in the Procambarus clarkii samples ranged from 63.3% to 104.7% with RSDs of 6.9%-14.5% (n=7). The proposed method is quick, simple and sensitive, and suitable for the rapid determination and analysis of pendimethalin in Procambarus clarkii samples.

An Optimized and Sensitive Pharmacokinetic Quantitative Method of Investigating Gastrodin, Parishin, and Parishin B, C and E in Beagle Dog Plasma using LC-MS/MS after Intragastric Administration of Tall Gastrodia Capsules.

Gastrodia elata Blume, called Tianma in China, has been widely used to treat headaches, convulsions and epilepsy for thousands of years. In the present study, a series of optimizations were employed to develop a rapid, sensitive, and reliable high-performance liquid chromatography-triple quadrupole mass spectrometry method, which was then used for the simultaneous determination of gastrodin, parishin, parishin B, parishin C and parishin E in beagle dog plasma after intragastric administration of tall Gastrodia capsules (Tianma brand). The chromatographic separation was achieved on a C18 column with gradient elution by using a mixture of 0.4% formic acid aqueous solution and acetonitrile as the mobile phase at a flow rate of 0.15 mL/min. A tandem mass spectrometric detection was conducted using multiple-reaction monitoring (MRM) via electrospray ionization (ESI) source in negative ionization mode. Samples were pre-treated by a single-step protein precipitation with methanol, and bergenin was used as internal standard (IS). Under the optimized conditions, the lower limit of quantification (LLOQ) was 0.10 ng/mL for gastrodin, 0.40 ng/mL for parishin B, 0.02 ng/mL for parishin E and 0.20 ng/mL for parishin and parishin C, all of which previously were the highest levels of sensitivity. The methods were optimized for selectivity, calibration curves, accuracy and precision. Extraction recoveries, matrix effects and stability were within acceptable ranges. Pharmacokinetic parameters of the tested substances were also quantitatively determined. Finally, a possible metabolic pathway was induced based on correlations obtained from quantitative and qualitative data analysis in vivo.

Determination of seven fluorescent whitening agents in flour by high performance liquid chromatography-triple quadrupole mass spectrometry

Determination of seven fluorescent whitening agents in flour by high performance liquid chromatography-triple quadrupole mass spectrometry

Determination of 34 illegally adulterated weight loss compounds in foods by ultra high performance liquid chromatography- triple quadrupole mass spectrometry

An analytical method was developed for the determination of 34 illegally adulterated weight loss compounds in foods and dietary supplements by ultra high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS). A Waters CORTECS T3 column (100 mm×2.1 mm, 2.7 μm) was used with 0.1% (v/v) formic acid aqueous solution-acetonitrile containing 0.1% (v/v) formic acid as mobile phases by gradient elution. The compounds were detected by electrospray ion source in positive or negative mode with multiple reaction monitoring (MRM) mode. The calibration curves showed good linearity in the range of 0.5-10 μg/L for 29 compounds such as sibutramine, and in the range of 2.5-50 μg/L for five compounds such as chlorothiazide. The correlation coefficients (r) of the standard calibration curves for the 34 analytes were all greater than 0.99. The recoveries of the 29 compounds at spiked levels of 5, 10 and 20 μg/kg were in the range of 49.2%-136.2%, and the RSDs were 0.7%-15.0% (n=6). The recoveries of the five compounds at spiked levels of 25, 50 and 100 μg/kg were in the range of 51.5%-130.9%, and the RSDs were 0.8%-14.0% (n=6). The limits of detection (LODs) and limits of quantification (LOQs) were 5 μg/kg and 10 μg/kg for the 29 compounds, 25 μg/kg and 50 μg/kg for the five compounds, respectively. The method was successfully applied to the analysis of actual samples, and 12 compounds were checked out, which combated the illegal adulteration behavior effectively.

High-sensitivity detection of biogenic amines with multiple reaction monitoring in fish based on benzoyl chloride derivatization

In this study an efficient and sensitive method for biogenic amines detection was established by combining rapid extraction and derivatization with multiple reaction monitoring (MRM) based on ultra high performance liquid chromatography-triple quadrupole mass spectrometry. Bead-beating disruption and extraction using 5-sulfosalicylic acid not only improved the extraction efficiency but also was environmentally friendly. Benzoyl chloride derivatization could obtain stable biogenic amine derivatives with a shorter reaction time. By combining with MRM detection mode, higher detection sensitivity for biogenic amines could be achieved. The method showed a good linearity with linear range of 3–4 orders of magnitude and regression coefficients ranging from 0.9966 to 0.9999. The limit of detection and limit of quantitation could even reach lower pg/mL level. Satisfactory recovery was obtained from 74.9% to 119.3%. And the derivatives were stable within 48h at 4°C. The method established was used to determine content of biogenic amines in different fishes at different storage conditions. The results indicated that this method was suitable for analysis of biogenic amines.

Qualitative and quantitative analysis of the chemical constituents in Mahuang-Fuzi-Xixin decoction based on high performance liquid chromatography combined with time-of-flight mass spectrometry and triple quadrupole mass spectrometers.

High-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF/MS) and high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-QQQ/MS/MS) were utilized to clarify the chemical constituents of Mahuang-Fuzi-Xixin Decoction. There are 52 compounds, including alkaloids, amino acids and organic acids were identified or tentatively characterized by their characteristic high resolution mass data by HPLC-QQQ/MS/MS. In the subsequent quantitative analysis, 10 constituents, including methyl ephedrine, aconine, songrine, fuziline, neoline, talatisamine, chasmanine, benzoylmesaconine, benzoylaconine and benzoylhypaconine were simultaneously determined by HPLC-QQQ/MS/MS with multiple reaction monitoring mode. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r > 0.9992). The relative standard deviations (RSD) of inter- and intra-day precisions were <3%. This method was also validated by repeatability, stability and recovery with RSD <3% respectively. A highly sensitive and efficient method was established for chemical constituents studying, including identification and quantification of Mahuang-Fuzi-Xixin decoction.

Cleaning Up Vegetable Samples Using a Modified “QuEChERS” Procedure for the Determination of 17 Plant Growth Regulator Residues by Ultra High Performance Liquid Chromatography–Triple Quadrupole Linear Ion Trap Mass Spectrometry

A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample pretreatment method coupled with ultra high performance liquid chromatography–triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) was developed for simultaneous determination of 17 plant growth regulator (PGR) residues in vegetables. Generik ChlorF (GCF) was used as one of the adsorbents in modified QuEChERS procedure, which can selectively remove the chlorophyll of acetonitrile extract without causing the losses of PGRs that have planar structure. To achieve the optimum performance toward the target analytes, extraction solvent, the type of adsorbent, and the amount of the adsorbent were investigated. Under the optimized conditions, good linearities with correlation coefficients (γ) higher than 0.9954 were obtained. The new method provided sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ). The LOD varied between 0.01 and 0.70 μg/kg and the LOQ varied between 0.04 and 2.32 μg/kg. Acceptable recoveries ranging from 78.5 to 116.8 % with the relative standard deviations (RSDs) of 0.9–11.9 % were achieved. The evaluated method provided reliable screening, quantification, and identification of 17 PGRs in vegetables.