关键词: 气相色谱-质谱法, 分散剂, 喹啉, 不确定度

Abstract: As an important chemical substance, quinoline is widely used in the synthesis of various chemical products. The key raw materials for synthesizing dispersing agents contain quinoline. Due to the advantage of improving brightness and uniformity of dyestuff, dispersing agents are heavily used as additives in the process of the commercialization of disperse dye in textile dyeing and finishing industry. In addition, they also serve as an auxiliary tanning agent and a stabilizing agent in leather industry and rubber industry. At present, residual quinoline in dispersing agents cannot be effectively removed, and it will consist in down-stream products along with the application of dispersing agents. Taking the usage of disperse dye as an example, quinoline can remain on fabrics and in wastewater during dyeing and finishing processes. According to research report, it can not only cause headache, dizziness, nausea and other adverse reactions, but also has comparatively high biotoxicity to human body by the way of steam inhalation and skin contact. Meanwhile, quinoline is difficultly biodegradable and has long-time stability in environment. Therefore, it is necessary to be controlled and supervised as a poisonous chemical substance by the means of determination of quinoline in dispersing agents. The latest state standard of determination of quinoline is GB/T 37505－2019 Surface Active Agents—Determination of Quinoline Content in Dispersing Agents. Evaluation uncertainty of the determination of quinoline content is beneficial to improving the reliability of the measuring result, and can provide proof for the avoidance and traceability of experimental errors. In this paper, the uncertainty that may occur in the measurement of quinoline content is evaluated. In terms of JJF 1059.1－2012 Evaluation and Expression of Uncertainty in Measurement and CNAS-GL006－2019 Guidance on Quantifying Uncertainty in Chemical Analysis, the mathematical model of uncertainty evaluation is established, the resources of the uncertainty are discerned, and the evaluation methods of each uncertainty component are proposed. Through the analysis and evaluation of each uncertainty component, all the uncertainty components are synthesized, and the synthetic relative standard uncertainty and extended uncertainty are given. It is concluded that uncertainty components associated with the purity and mass weighing of standard materials and the random factors of the repeated determination of parallel sample process have certain contribution to the gross uncertainty, and the preparation of standard working solutions, the linear fitting of standard curves, and the standard addition recovery have the great influence on the uncertainty. The analysis results from the measurement of gas chromatography-mass spectrometry show that when the confidence interval is 95%, the concentration of quinoline in the dispersing agent is 95.36 mg/kg and the expanded uncertainty is 6.94 mg/kg (k=2). In the process of experiment, the standard material which is given with less uncertainly of relative extension should be selected, and the analytical balance needs to be calibrated periodically. The number of unnecessary dilution step of preparing standard working solutions should be reduced. Furthermore, appropriate standard curve range, normative operation of experimenter and stable experimental environment can improve the accuracy of the measurement results. The uncertainty evaluation study can provide reference for the uncertainty evaluation of gas chromatography-mass spectrometry in the determination of quinoline content in dispersing agents.

Key words:

gas chromatography-mass spectrometer, dispersing agent, quinoline, uncertainty