Wang Bing, Shen Hao, Fang Aiqin, Huang De-Shuang, Jiang Changjun, Zhang Jun, Chen Peng
College of Electronics and Information Engineering, Tongji University, Shanghai 201804, China; The Advanced Research Institute of Intelligent Sensing Network, Tongji University, Shanghai 201804, China; The Key Laboratory of Embedded System and Service Computing, Tongji University, Shanghai 201804, China.
College of Electronics and Information Engineering, Tongji University, Shanghai 201804, China.
J Chromatogr A. 2016 Jun 17;1451:127-134. doi: 10.1016/j.chroma.2016.04.068. Epub 2016 Apr 26.
Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC/TOF-MS) system has become a key analytical technology in high-throughput analysis. Retention index has been approved to be helpful for compound identification in one-dimensional gas chromatography, which is also true for two-dimensional gas chromatography. In this work, a novel regression model was proposed for calculating the second dimension retention index of target components where n-alkanes were used as reference compounds. This model was developed to depict the relationship among adjusted second dimension retention time, temperature of the second dimension column and carbon number of n-alkanes by an exponential nonlinear function with only five parameters. Three different criteria were introduced to find the optimal values of parameters. The performance of this model was evaluated using experimental data of n-alkanes (C7-C31) at 24 temperatures which can cover all 0-6s adjusted retention time area. The experimental results show that the mean relative error between predicted adjusted retention time and experimental data of n-alkanes was only 2%. Furthermore, our proposed model demonstrates a good extrapolation capability for predicting adjusted retention time of target compounds which located out of the range of the reference compounds in the second dimension adjusted retention time space. Our work shows the deviation was less than 9 retention index units (iu) while the number of alkanes were added up to 5. The performance of our proposed model has also been demonstrated by analyzing a mixture of compounds in temperature programmed experiments.
全二维气相色谱-飞行时间质谱（GC×GC/TOF-MS）系统已成为高通量分析中的关键分析技术。保留指数已被证明有助于一维气相色谱中的化合物鉴定，在二维气相色谱中也是如此。在这项工作中，提出了一种新的回归模型，用于计算以正构烷烃为参考化合物的目标组分的第二维保留指数。该模型通过一个仅含五个参数的指数非线性函数来描述调整后的第二维保留时间、第二维柱温与正构烷烃碳数之间的关系。引入了三种不同的标准来寻找参数的最优值。使用正构烷烃（C7-C31）在24个温度下的实验数据对该模型的性能进行了评估，这些温度可以覆盖所有0-6s的调整保留时间区域。实验结果表明，预测的正构烷烃调整保留时间与实验数据之间的平均相对误差仅为2%。此外，我们提出的模型在预测第二维调整保留时间空间中位于参考化合物范围之外的目标化合物的调整保留时间方面具有良好的外推能力。我们的工作表明，当添加的烷烃数量达到5种时，偏差小于9个保留指数单位（iu）。通过在程序升温实验中分析化合物混合物，也证明了我们提出的模型的性能。
