Determination of Xipamide metabolite in human urine by high‐performance liquid chromatography/diode‐array detection,high‐performance liquid chromatography/electrospray ionization mass spectrometry and gas chromatography/mass spectrometry

The original article to which this Erratum refers was published in Rapid Commun. Mass Spectrom. 2004; 18 : 2505–2512     

Quality evaluation of Hpericum japomicum by using high‐performance liquid chromatography coupled with photodiode array detector and electrospray ionization tandem mass spectrometry

A high‐performance liquid chromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry (HPLC‐PAD‐ESI‐MSⁿ) method was developed to evaluate the quality of Hpericum japomicum through establishing chromatographic fingerprint and simultaneous determination of seven phenolic compounds. The analysis was achieved on an Ultimate XB‐C₁₈ analytical column (250 mm × 4.6 mm i.d., 5 µm) using an aqueous solution of acetic acid (pH 3.8) and methanol as the mobile phase. Ten samples of H. japomicum from various habitats were investigated and the correlation coefficients of similarity were determined from the HPLC fingerprints. By using an online ESI‐MSⁿ, 20 common peaks in chromatographic fingerprints were identified as phenols, including flavones and their glycosides, flavonones and their glucosides, flavanols, xanthones, phloroglucinols, phenyl propanoids and chromones. Based on the above study, seven phenols which are considered to be major constituents in H. japomicum, including 3,4‐dihydroxybenzoic acid (1), taxfolin‐7‐O‐α‐l ‐rhamnoside (7), 7‐dihydroxy‐2‐(1‐methylpropyl)chromone‐8‐β‐d ‐glucoside (8), isoquercitrin (14), quercitrin (16), quercetin‐7‐O‐α‐l‐ rhamnoside (18) and quercetin (19) were quantified by the validated HPLC‐PAD method. This developed method by combination of chromatographic fingerprint and quantification analysis could be applied to control the quality of H. japomicum. Copyright © 2009 John Wiley & Sons, Ltd.     

Quality assessment of Cortex Phellodendri by high‐performance liquid chromatography coupled with electrospray ionization mass spectrometry

A simple method based on liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (LC‐DAD‐ESI‐MS) was developed for the quality assessment of Cortex Phellodendri (CP), which was mainly derived from two species of Phellodendron chinense Schneid and Phellodendron amurense Rupr. Total 41 compounds, including 14 phenols, 24 alkaloids and three liminoidal triterpenes were identified or tentatively characterized from the 75% methanol extract of CP samples by online ESI‐MSⁿ fragmentation and UV spectra analysis. Among them, two phenols and six alkaloids were simultaneously quantified using HPLC‐DAD method. The validated HPLC‐DAD method showed a good linearity, precision, repeatability and accuracy for the quantification of eight marker compounds. Furthermore, the plausible fragmentation pathway of the representative compounds were proposed in the present study. The differences of the chemical constituents content and the comprehensive HPLC profiles between the two CP species using LC‐DAD‐ESI‐MS method are reported for the first time, indicating that the CP drugs from different resources should be used separately in the clinic. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of Amaryllidaceae alkaloids from Crinum by high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

A high‐performance liquid chromatography/electrospray ionization multi‐stage tandem mass spectrometry (HPLC/ESI‐MSⁿ) method was developed to analyze two structurally related groups of Amaryllidaceae alkaloids (AmAs), crinane‐ and tazettine‐type alkaloids, in the species Crinum latifolium and C. asiaticum, as well as different organs of C. latifolium. In ESI‐MSⁿ spectra of the two types of alkaloids, characteristic fragmentation reactions were observed that allowed us to determine and differentiate them. Based on the fragmentation rules of reference standards, crinane‐type alkaloids displayed concurrent neutral loss of C₂H₅N (43 u) and C₂H₆N (44 u) as well as characteristic ions of m/z 213 and 211, whereas tazettine‐type alkaloids exhibited neutral loss of C₃H₇N (57 u) [or C₂H₅N (43 u), C₃H₇NO (73 u)] from the [M+H]⁺ and [M+H–H₂O]⁺ ions. These were supported by quadrupole time‐of‐flight (Q‐Tof)‐MS/MS analysis. The chemical complexity of the mixture was resolved by profiling. The compositions of the main crinane‐ and tazettine‐type alkaloids in the above‐mentioned species and organs were also compared. Overall, 28 AmAs comprising 14 crinane‐type and 14 tazettine‐type alkaloids were identified and studied by MS. Among them, 14 AmAs were tentatively characterized from the two species for the first time. This method allowed a rapid analysis of alkaloid distribution and composition of Crinum species, and may also be used for quality control and screening of extracts designated for pharmaceutical application. Copyright © 2009 John Wiley & Sons, Ltd.     

Pharmacokinetic and metabolism studies of bavachinin through ultra‐high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

Bavachinin (BVC), one of the main bioactive prenylated flavonoids derived from Psoralea corylifolia Linn, has a wide variety of pharmacological effects, such as antiangiogenic, antitumor, antiallergic, anti‐inflammatory and antibacterial activities, especially as a pan‐peroxisome proliferator‐activated receptors agonist. A rapid and sensitive method for quantifying BVC in rat plasma was developed and validated through ultra‐high‐performance liquid chromatography coupled with electrospray‐ionization tandem mass spectrometry. Furthermore, a complete metabolic investigation of BVC was performed through ultra‐high‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry. In the pharmacokinetic analysis, BVC exhibited rapid oral absorption (T_max = 0.68 ± 0.21 h), good elimination (T_1/2 = 2.27 ± 1.63 h) following oral administration and poor absolute bioavailability (5.27%). Moreover, 11 metabolites of BVC in plasma, urine, bile and feces were characterized. The main metabolic pathways of BVC involved isomeriszation, glucuronidation, sulfonation, hydroxylation, methoxylation and reduction. In conclusion, the present study provides a sensitive quantitative method with a lower limit of quantification of 1 ng/mL and an improved comprehension of the physiological disposition of BVC.     

Identification and analysis of alkaloids in cortex Phellodendron amurense by high‐performance liquid chromatography with electrospray ionization mass spectrometry coupled with photodiode array detection

Alkaloids from Cortex Phellodendron amurense Rupr. were identified to determine the material basis for the bioactivity of this herb. HPLC–ESI‐MS with photodiode array detection coupled to XCharge C₁₈ column was applied to analyze the alkaloids qualitatively and quantitatively. A total of 37 alkaloids were identified and tentatively characterized from the ethanol extract by online ESI‐MSⁿ fragmentation and UV spectral analysis. A total of ten alkaloids, including four novel natural products, were tentatively identified for the first time in P. amurense. The fragmentation pathways for certain compounds were analyzed. The contents of a pair of isomers (columbamine and jatrorrhizine) and four main alkaloids (phellodendrine, magnoflorine, berberine, and palmatine) were simultaneously quantified using the aforementioned method. Results showed that the newly discovered and known components of P. amurense were helpful in determining the material basis for the bioactivity of the herb. The application of the XCharge C₁₈ column is a suitable and practical method for the isolation of alkaloids in plants.     

Rapid analysis of long‐chain glycolipids in heterocystous cyanobacteria using high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry

Under nitrogen‐depleted conditions, N₂‐fixing cyanobacteria of the order Nostocales and Stigonematales differentiate vegetative cells into heterocysts. The cell envelope of these specialized cells contains unique glycolipids, consisting of a sugar moiety glycosidically bound to long‐chain diols, triols and hydroxyketones. Only few reports have been published on these glycolipids in cultured cyanobacteria and none has reported them in natural environments. Here we show that heterocyst glycolipids can be rapidly and sensitively analyzed using high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC/ESI‐MS²). Positive ion mass spectra of the glycolipids consisted of protonated molecules and diagnostic product ions, indicating losses of sugar groups as well as hydroxyl and carbonyl functionalities from an alkyl chain. Using this method, heterocyst glycolipids were for the first time identified in a natural ecosystem, i.e., a microbial mat from the North Sea barrier island Schiermonnikoog, The Netherlands. This technique will facilitate the quick screening of cyanobacterial cultures and natural environments for the presence of heterocyst glycolipids, which may aid in assessing the role of heterocystous cyanobacteria in the global nitrogen cycle. Copyright © 2009 John Wiley & Sons, Ltd.     

高效液相色谱-电喷雾串联质谱法测定饲料中的N-氨基甲酰-L-谷氨酸

建立了高效液相色谱-电喷雾串联质谱(HPLC-ESI-MS/MS)测定饲料中N-氨基甲酰-L-谷氨酸(NCG)含量的方法。饲料样品经甲醇提取、混合型强阴离子交换反相固相萃取(PXA)柱净化、HPLC分离后,采用ESI-MS/MS在正离子多反应监测(MRM)模式下进行检测,以碎片离子m/z 148.0和m/z 84.0进行定性,以碎片离子m/z 130.0进行定量。NCG的检出限(S/N >3)为24 μg/kg,定量限(S/N >10)为80 μg/kg,在20~1000 μg/L的质量浓度范围内峰面积与含量的线性关系良好,相关系数为0.9999。对饲料中NCG在80、200、500 mg/kg等3个添加水平下的回收率进行了测定,分别为104.0%、103.5%、95.3%,相对标准偏差分别为7.5%、6.3%、5.8%。结果表明,该方法操作简单,净化效果好,快速,灵敏度和准确度高,符合对饲料样品中NCG检测分析的要求。     

Screening and analysis of the multiple absorbed bioactive components and metabolites in rat plasma after oral administration of Jitai tablets by high‐performance liquid chromatography/diode‐array detection coupled with electrospray ionization tandem mass spectrometry

Based on the serum pharmacochemistry technique and high‐performance liquid chromatography/diode‐array detection (HPLC/DAD) coupled with electrospray tandem mass spectrometry (HPLC/ESI‐MS/MS), a method for screening and analysis of the multiple absorbed bioactive components and metabolites of Jitai tablets (JTT) in orally dosed rat plasma was developed. Plasma was treated by methanol precipitation prior to liquid chromatography, and the separation was carried out on a Symmetry C₁₈ column, with a linear gradient (0.1% formic acid/water/acetonitrile). Mass spectra were acquired in negative and positive ion modes, respectively. As a result, 26 bioactive components originated from JTT and 5 metabolites were tentatively identified in orally dosed rat plasma by comparing their retention times and MS spectra with those of authentic standards and literature data. It is concluded that an effective and reliable analytical method was set up for screening the bioactive components of Chinese herbal medicine, which provided a meaningful basis for further pharmacology and active mechanism research of JTT. Copyright © 2010 John Wiley & Sons, Ltd.     

Identification of complex,naturally occurring flavonoid glycosides in kale (Brassica oleracea var. sabellica) by high‐performance liquid chromatography diode‐array detection/electrospray ionization multi‐stage mass spectrometry

Kale is a member of the Brassicaceae family and has a complex profile of flavonoid glycosides. Therefore, kale is a suitable matrix to discuss in a comprehensive study the different fragmentation patterns of flavonoid glycosides. The wide variety of glycosylation and acylation patterns determines the health‐promoting effects of these glycosides. The aim of this study is to investigate the naturally occurring flavonoids in kale. A total of 71 flavonoid glycosides of quercetin, kaempferol and isorhamnetin were identified using a high‐performance liquid chromatography diode‐array detection/electrospray ionization multi‐stage mass spectrometry (HPLC‐DAD/ESI‐MSⁿ) method. Of these 71 flavonol glycosides, 27 were non‐acylated, 30 were monoacylated and 14 were diacylated. Non‐acylated flavonol glycosides were present as mono‐, di‐, tri‐ and tetraglycosides. This is the first time that the occurrence of four different fragmentation patterns of non‐acylated flavonol triglycosides has been reported in one matrix simultaneously. In addition, 44 flavonol glycosides were acylated with p‐coumaric, caffeic, ferulic, hydroxyferulic or sinapic acid. While monoacylated glycosides existed as di‐, tri‐ and tetraglycosides, diacylated glycosides occurred as tetra‐ and pentaglycosides. To the best of our knowledge, 28 compounds in kale are reported here for the first time. These include three acylated isorhamnetin glycosides (isorhamnetin‐3‐O‐sinapoyl‐sophoroside‐7‐O‐D‐glucoside, isorhamnetin‐3‐O‐feruloyl‐sophoroside‐7‐O‐diglucoside and isorhamnetin‐3‐O‐disinapoyl‐triglucoside‐7‐O‐diglucoside) and seven non‐acylated isorhamnetin glycosides. Copyright © 2010 John Wiley & Sons, Ltd.     

Characterization of anti‐Coxsackie virus B3 constituents of Radix Astragali by high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

To profile the anti‐Coxsackie virus B3 constituents of Radix Astragali, an HPLC‐DAD‐MSⁿ analytical method, combined with an in vivo test, has been developed to identify the constituents of the active part, which has been demonstrated to have potency to inhibit the proliferation of virus in cardiac muscle, alleviate infraction in heart and elevate the survival rate of the animal. By comparing their retention time and MS data with those obtained from the authentic compounds and the published data, a total of 19 compounds, including 11 isoflavonoids and eight saponins, were identified, among which one pterocarpane glucoside was reported for the first time. The present study provides an approach to rapidly screening bioactive constituents in traditional Chinese medicines. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous analysis of ten phytohormones in Sargassum horneri by high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry

Phytohormones have attracted wide attention due to their important biological functions. However, their detection is still a challenge because of their complex composition, low abundance and diverse sources. In this study, a novel method of high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry was developed and validated for the simultaneous determination of ten phytohormones including indole‐3‐acetic acid, isopentenyladenine, isopentenyl adenosine, trans‐zeatin riboside, zeatin, strigolactones, abscisic acid, salicylic acid, gibberellin A3, and jasmonic acid in Sargassum horneri (S. horneri). The phytohormones were extracted from freeze‐dried S. horneri with methanol/water/methanoic acid (15:4:1, v/v/v) analyzed on a Hypersil Gold C₁₈ column and detected by electrospray ionization tandem triple quadrupole mass spectrometry in the multiple reaction monitoring mode. The experimental conditions for the extraction and analysis of phytohormones were optimized and validated in terms of reproducibility, linearity, sensitivity, recovery, accuracy, and stability. Distributions of the phytohormones in the stems, blades, and gas bladder of the S. horneri in drift, fixed, and semi‐fixed growing states were investigated for the first time. The observed contents of the phytohormones in S. horneri range from not detected to 5066.67 ng/g (fresh weight). Most phytohormones are distributed mainly in the stems of S. horneri in drift and semi‐fixed states.     

Microcolumn size-exclusion chromatography coupled with electrospray ionization mass spectrometry

Microcolumn (250 x 0.5 mm I.D.) size-exclusion chromatography was implemented for the separation of polydisperse mixtures prior to electrospray ionization (ESI) mass spectrometric detection. An improved separation, compared to conventional-bore SEC, was demonstrated upon coupling with ESI quadrupole ion-trap mass spectrometry and a Fourier transform ion cyclotron resonance instrument for the separation of individual oligomers present in octylphenoxypoly(ethoxy)ethanol.     

啤酒中单糖的衍生化HPLC-ESI-MS测定方法研究

单糖类样品在溶液中非常稳定,难于离子化,不适合于进行ESI-MS检测。采用1-苯基-3-甲基-5-吡唑啉酮(PMP)将糖类物质衍生化,HPLC-ESI-MS在线联用,选择性离子扫描方式对几种啤酒样品中的5种单糖进行了分离检测。检出限可达到80pg。