Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples.
Liquid and gas chromatography coupled to isotope ratio mass spectrometry for the determination of 13C-valine isotopic ratios in complex biological samples.
复制标题
液相色谱和气相色谱与同位素比质谱联用，用于测定复杂生物样品中的 13C-缬氨酸同位素比。
作者：
J. Godin;D. Breuillé;C. Obled;I. Papet;H. Schierbeek;G. Hopfgartner;L. Fay
在线气相色谱-燃烧-同位素比值质谱法（GC-C-IRMS）通常用于测量自然丰度的同位素比率以及营养和医学研究中的示踪剂研究。然而，高精度（13）C同位素富集也可以通过液相色谱-同位素比值质谱（LC-IRMS）来测量。事实上，LC-IRMS可以用来获得一个基线分离，并测量（13）C同位素富集的未分解氨基酸（Asp, Thr-Ser, Glu, Pro, Gly, Ala， Cys和Val）。以Val为例，在自然丰度下，用该方法报告的SD（δ (13)C）低于1 / 1000。本文报道的新LC-IRMS方法的另一个关键特征是LC-IRMS方法与传统GC-C-IRMS测定方法的比较。为了进行这项比较研究，对未分解的Val及其N(O， S)-乙氧羰基乙基酯衍生物进行了同位素富集测量。在0.0 ~ 1.0摩尔百分数（MPE）范围内（δ (13)C= -12.3 ~ 150.8 /千），GC-C-IRMS和LC-IRMS的SD计算均方根（rms）分别为0.38和0.46 /千，精度计算均方根（rms）分别为0.023和0.005 MPE。两种系统都精确地测量了低同位素富集（0.002原子百分数过剩（APE））， SD （APE）为0.0004。为了将GC-C-IRMS和LC-IRMS测量的Val的相对（δ (13)C）和绝对（原子百分比、APE和MPE）同位素富集进行关联，建立了曲线斜率和截距的数学方程，并用0.0 ~ 2.3 MPE的实验数据进行了验证。最后，在对大鼠进行的示踪研究中，GC-C-IRMS和LC-IRMS仪器也被用于评估胫骨骨骺中蛋白结合（13）C-Val的同位素富集。LC-IRMS和GC-C-IRMS测定的同位素丰度差异无统计学意义（p < 0.05）。本工作的结果表明，LC-IRMS在示踪剂研究中成功地进行了高精度的（13）C同位素测量，得到了与GC-C- irms相似的（13）C同位素富集，但没有GC衍生化步骤。因此，对于需要高精度同位素测量的临床研究，LC-IRMS是测量同位素比的首选方法。
On-line gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is commonly used to measure isotopic ratios at natural abundance as well as for tracer studies in nutritional and medical research. However, high-precision (13)C isotopic enrichment can also be measured by liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). Indeed, LC-IRMS can be used, as shown by the new method reported here, to obtain a baseline separation and to measure (13)C isotopic enrichment of underivatised amino acids (Asp, Thr-Ser, Glu, Pro, Gly, Ala, Cys and Val). In case of Val, at natural abundance, the SD(delta(13)C) reported with this method was found to be below 1 per thousand . Another key feature of the new LC-IRMS method reported in this paper is the comparison of the LC-IRMS approach with the conventional GC-C-IRMS determination. To perform this comparative study, isotopic enrichments were measured from underivatised Val and its N(O, S)-ethoxycarbonyl ethyl ester derivative. Between 0.0 and 1.0 molar percent excess (MPE) (delta(13)C= -12.3 to 150.8 per thousand), the calculated root-mean-square (rms) of SD was 0.38 and 0.46 per thousand and the calculated rms of accuracy was 0.023 and 0.005 MPE, respectively, for GC-C-IRMS and LC-IRMS. Both systems measured accurately low isotopic enrichments (0.002 atom percent excess (APE)) with an SD (APE) of 0.0004. To correlate the relative (delta(13)C) and absolute (atom%, APE and MPE) isotopic enrichment of Val measured by the GC-C-IRMS and LC-IRMS devices, mathematical equations showing the slope and intercept of the curves were established and validated with experimental data between 0.0 to 2.3 MPE. Finally, both GC-C-IRMS and LC-IRMS instruments were also used to assess isotopic enrichment of protein-bound (13)C-Val in tibial epiphysis in a tracer study performed in rats. Isotopic enrichments measured by LC-IRMS and GC-C-IRMS were not statistically different (p>0.05). The results of this work indicate that the LC-IRMS was successful for high-precision (13)C isotopic measurements in tracer studies giving (13)C isotopic enrichment similar to the GC-C-IRMS but without the step of GC derivatisation. Therefore, for clinical studies requiring high-precision isotopic measurement, the LC-IRMS is the method of choice to measure the isotopic ratio.
富集胆固醇的化合物特异性碳同位素比测定。
影响因子：
7.4
作者：
Guo,ZK;Luke,AH;Lee,WP;Schoeller,D
通讯作者：
Schoeller,D
影响因子：
7.4
作者：
GOODMAN, KJ;BRENNA, JT
通讯作者：
BRENNA, JT
测量大鼠模型中皮肤蛋白质的分解。
DOI：
10.1152/ajpendo.2000.279.4.e900
发表时间：
2000
期刊：
American journal of physiology. Endocrinology and metabolism
影响因子：
--
作者：
Volpi,E;Jeschke,MG;Herndon,DN;Wolfe,RR
通讯作者：
Wolfe,RR