Low-temperature Electronic Paramagnetic Resonance Measurements of TEMPO and 4-Hydroxy-TEMPO Benzoate for Purity Analyses by the Effective Magnetic-moment Method
Low-temperature Electronic Paramagnetic Resonance Measurements of TEMPO and 4-Hydroxy-TEMPO Benzoate for Purity Analyses by the Effective Magnetic-moment Method
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DOI：
10.2116/analsci.33.1059
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发表时间：
2017-09
影响因子：
1.6
通讯作者：
N. Matsumoto;T. Shimosaka
中科院分区：
文献类型：
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作者：
N. Matsumoto;T. Shimosaka
两个高纯度的有机化合物与硝酰基自由基部分的纯度进行了定量的基础上，其自由基含量使用的有效磁矩的方法。利用超导量子干涉仪和X波段电子顺磁共振（EPR）谱仪分别测量了样品的磁矩和近室温至近液氦温度范围内的X波段EPR谱。关于使用EPR光谱仪测量有效g值，考虑扫描方向和扫描速度以获得准确的g值。2，2，6，6-四甲基哌啶1-氧基（克里思）和4-羟基-2，2，6，6-四甲基哌啶1-氧基苯甲酸酯（4-羟基-TEMPO苯甲酸酯）的纯度接近1 kg kg^−1，相对不确定度为1%，与我们以前获得的值相比，这代表了改进的值。这些结果表明，这两种化合物作为参考材料，提供可靠的定量的自由基每单位质量使用这种分析方法的可能性。
The purities of two high-purity organic compounds with a nitroxyl radical moiety were quantified based on their free-radical content using the effective magnetic-moment method. Magnetic moments were measured and X-band electron paramagnetic resonance (EPR) spectra were obtained using a superconducting quantum interference device and X-band EPR spectrometer, respectively, over a wide temperature range of near-room temperature to near-liquid-helium temperature. Concerning measurements of effective g -values using an EPR spectrometer, both the sweep direction and sweep speed were taken into account to obtain accurate g -values. The purities of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl benzoate (4-hydroxy-TEMPO benzoate) were close to 1 kg kg^−1 with relative uncertainties of 1%, which represented improved values compared to those obtained by us previously. These results show a possibility for both compounds to act as reference materials in providing reliable quantification of free radicals per unit mass using this analytical method.