Highly sensitive and selective analysis of urinary steroids by comprehensive two-dimensional gas chromatography combined with positive chemical ionization quadrupole mass spectrometry.
Highly sensitive and selective analysis of urinary steroids by comprehensive two-dimensional gas chromatography combined with positive chemical ionization quadrupole mass spectrometry.
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通过综合二维气相色谱法结合正化学电离四极杆质谱法对尿类固醇进行高灵敏度和选择性分析。
DOI：
10.1039/c2an35087d
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Brenna,JThomas
中科院分区：
文献类型：
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作者：
Zhang,Ying;Tobias,HerbertJ;Brenna,JThomas
全二维气相色谱（GC × GC）比常规气相色谱提供了更大的分离空间。由于快速峰洗脱，飞行时间质谱仪（TOFMS）是通常选择的结构特异性检测器。采用电子电离（EI）、甲烷或氨正离子化学电离（PCI）技术，研究了新型GC × GC快速四极杆质谱（GC × GC Fast Quadrupole MS）对兴奋剂检测中内源性尿中类固醇的定量分析能力。从重复尿液提取的类固醇定量分析的平均精密度为6%（RSD）的EI和8%的PCI-NH3。通过定量离子计算的12种目标类固醇加标到无类固醇尿基质（SFUM）的平均检测限（LOD）为2.6 ng mL−1（EI）、1.3 ng mL−1（PCI-CH 4）和0.3 ng mL−1（PCI-NH 3），均采用质量扫描模式。全质量扫描GC × GC-qMS测定的定量限（LOQ）与选择离子监测（SIM）模式下一维GC-MS测定的LOQ值相当。PCI-NH3比EI或PCI-CH 4产生更少的碎片和更大的（假）分子离子丰度。这些数据表明，台式GC × GC-qMS系统具有分析正常尿液浓度下的尿类固醇的灵敏度、特异性和分辨率，并且目前大多数GC × GC-TOFMS仪器上不可用的PCI-NH3对于产生结构特异性离子具有特别的价值。
Comprehensive two dimensional gas chromatography (GC × GC) provides greater separation space than conventional GC. Because of fast peak elution, a time of flight mass spectrometer (TOFMS) is the usual structure-specific detector of choice. The quantitative capabilities of a novel GC × GC fast quadrupole MS were investigated with electron ionization (EI), and CH4 or NH3 positive chemical ionization (PCI) for analysis of endogenous urinary steroids targeted in anti-doping tests. Average precisions for steroid quantitative analysis from replicate urine extractions were 6% (RSD) for EI and 8% for PCI-NH3. The average limits of detection (LODs) calculated by quantification ions for 12 target steroids spiked into steroid-free urine matrix (SFUM) were 2.6 ng mL−1 for EI, 1.3 ng mL−1 for PCI-CH4, and 0.3 ng mL−1 for PCI-NH3, all in mass scanning mode. The measured limits of quantification (LOQs) with full mass scan GC × GC-qMS were comparable with the LOQ values measured by one-dimensional GC-MS in selected ion monitoring (SIM) mode. PCI-NH3 yields fewer fragments and greater (pseudo)molecular ion abundances than EI or PCI-CH4. These data show that a benchtop GC × GC-qMS system has the sensitivity, specificity, and resolution to analyze urinary steroids at normal urine concentrations, and that PCI-NH3, not currently available on most GC × GC-TOFMS instruments, is of particular value for generation of structure-specific ions.