Negative Ion Tandem Mass Spectrometry for the Detection of Glutathione Conjugates

2005 ◽  
Vol 18 (4) ◽  
pp. 630-638 ◽  
Author(s):  
Christine M. Dieckhaus ◽  
Carmen L. Fernández-Metzler ◽  
Richard King ◽  
Paul H. Krolikowski ◽  
Thomas A. Baillie
Author(s):  
Xiabing Li ◽  
Wuqun Tao ◽  
Hang Xun ◽  
Xi Yao ◽  
Jin Wang ◽  
...  

AbstractAn analytical method for the simultaneous determination of ten major functional flavonoids (isoorientin, orientin, vitexin, isovitexin, apigenin, luteolin, tricin, quercetin, rutin, and kaempferol) in different bamboo species was developed by liquid chromatography-tandem mass spectrometry. Chromatographic separation was carried out on a reversed-phase C-18 column with acetonitrile and water as the mobile phases. Detection was performed in negative ion electrospray ionization mode using multiple reaction monitoring mode. The correlation coefficients for the calibration curves ranged from 0.9955 to 0.9997. The limit of detection ranged from 1 to 45 ng/ml. The applicability of this analytical approach was confirmed by the successful analysis of real leaf samples of four bamboo species, family Poaceae: Pleioblastus amarus (Keng) Keng f., Phyllostachys glauca McClure, Phyllostachys edullis (Carrière) J.Houz, and Indocalamus latifolius (Keng) McClure. The total flavonoid contents were 3321.09, 3095.96, 4037.33, and 2808.42 mg/kg for P. amarus, P. glauca, P. edullis, and I. latifolius, respectively. Graphical abstract


Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 389 ◽  
Author(s):  
Xiangsheng Zhao ◽  
Shihui Zhang ◽  
Dan Liu ◽  
Meihua Yang ◽  
Jianhe Wei

Dalbergia odorifera, a traditional Chinese medicine, has been used to treat cardio- and cerebrovascular diseases in China for thousands of years. Flavonoids are major active compounds in D. odorifera. In this paper, a rapid and sensitive ultra-high performance liquid chromatography-triple quadrupole mass spectrometry method was developed and validated for simultaneous determination of 17 flavonoids in D. odorifera. Quantification was performed by multiple reaction monitoring using electrospray ionization in negative ion mode. Under the optimum conditions, calibration curves for the 17 analytes displayed good linearity (r2 > 0.9980). The intra- and inter-day precisions (relative standard deviations) were lower than 5.0%. The limit of quantitation ranged from 0.256 to 18.840 ng/mL. The mean recovery range at three spiked concentrations was 94.18–101.97%. The validated approach was successfully applied to 18 samples of D. odorifera. Large variation was observed for the contents of the 17 analytes. Sativanone and 3′-O-methylviolanone were the dominant compounds. The fragmentation behaviors of six flavonoids were investigated using UPLC with quadrupole time-of-flight tandem mass spectrometry. In negative ion electrospray ionization mass spectrometry, all the flavonoids yielded prominent [M − H]− ions. Fragments for losses of CH3, CO, and CO2 were observed in the mass spectra. Formononetin, liquiritigenin, isoliquiritigenin, sativanone, and alpinetin underwent retro-Diels–Alder fragmentations. The proposed method will be helpful for quality control of D. odorifera.


2008 ◽  
Vol 3 ◽  
pp. ACI.S1005 ◽  
Author(s):  
Renata Raina ◽  
Patricia Hall

A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) with gas chromatography-tandem mass spectrometry (GC-MS/MS) in selected reaction monitoring (SRM) mode with both electron ionization (EI) and negative-ion chemical ionization (NCI) are presented for over 50 pesticides ranging from organochlorines (OCs), organophosphorus pesticides (OPs) and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin). The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations <100 pg µL-1 (< 100 pg m-3 in air). No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5-10 pg µL-1) along with best confirmation (<25% RSD of ion ratio), while GC-NCI/SRM is recommended for use where added selectivity or confirmation is required (such as parathion-ethyl, tokuthion, carbofenothion). GC-EI/SRM at concentration < 100 pg µL-1 was not suitable for most pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1-10 pg µL-1) for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT).


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