氮同位素丰度测定的计算机处理

Data Process in Measurement of Isotop Abundance of ^(15)N by Quadrupole Mass Spectrometer

同位素丰度测定在很多领域都有广泛的应用。目前国内外大都采用磁质谱计来测定稳定同位素丰度。磁质谱计的峰形好,测量精度高,一般均能优于1%甚至0.1%以上,但其价格常较贵。我们曾经尝试用四极质谱计来测定同位素丰度,实验证明:采用南京分析仪器厂生产的SZ-001型四极质谱计(杆系尺寸:极杆直径=6.5 mm,长度=100 mm,频率f=4.2 MHz,质量范围0～50 Amu)测定天然氮气同位素的精度可以达到1%。

In the paper it is stated how to use a single board computer in completing data sampling and data processing when the isotope abundance for ^(15)N is measured with the quadrupole mass spectromter, type SZ-001. That the sampling precision is ensured by means of the programble amplifier and the disturbance caused the sputter ion pump is filtered with the help of the software is discueeed mainly. The result shows that the measurement precision of the isotope abundance of ^(13)N can reach about 1%. It provides a useful esperience to use the quodrupole mass spectrometer in measurment of istope abundance.