How is Mass Spectroscopy different from other Spectroscopic Techniques?

质谱complements the information made available by other spectroscopic techniques. However, it is different in several respects from other光谱法分析方法and such differences will be highlighted in the present article.

光谱技术

Optical Spectroscopic techniques provide qualitative and quantitative information on light absorbing or emitting species present in samples. The basis of such spectroscopic techniques is interaction of electromagnetic radiation with matter. The interactions are specific for each species and vary with the wavelength of the incident electromagnetic radiation. Useful details are, however, provided only at wavelengths characteristic for each molecule or ionic species. Before proceeding to Mass spectroscopic techniques it would not be out of place to make a brief mention of the typical information provided by some popular optical spectroscopic techniques:

UV – VIS Spectroscopy

含有发色群的分子和具有不同程度共轭的分子的定性和定量估计。通过金属配体复合反应定量痕量金属是另一个主要应用。

FT - 红外光谱法

Identification and structural conformation of compounds having different functional groups. By and large it is mainly used for qualitative conformation of components for material characterization.

荧光光谱

Emission intensity measurements are recorded at a wavelength different from the excitation wavelength. Light of higher wavelength is emitted by the sample after absorption after a time gap on exposure to incident light of lower wavelength.

原子吸收光谱

定量测定不同样品矩阵中的痕量金属，通过在光源中存在的相同金属产生的特定波长下，原子在原子火焰或石墨炉中吸收光原子。

ICP - OES

通过在高温等离子体源中引入的样品元素在特定波长处发射光

质谱

Mass Spectroscopy is distinctly different from optical spectroscopy and it provides more details on the sample molecules.

蒸气相中的样品分子通过高能电子的撞击而被电离。通过磁性和/或静电场的带电分子与质量与电荷比（M/z）相关的圆形路径被偏转。单个电子的电离导致分子离子。由于其不稳定性，分子离子可以分解为较小的质量片段。根据离子化物质的M/Z比，偏转的离子束沿不同的圆路径加速。对磁场和或静电场的扫描将导致不同的碎片离子的不同路径，这些离子将在不同点到达检测器并生成检测器信号。

The main differences of mass spectroscopic from optical spectroscopic techniques are:

• Molecular species are characterized by their mass to charge ratios whereas the wavelengths of absorption and emission characterize molecular or ionic species in optical techniques.
• 除了鉴定外，还准确测定了感兴趣的离子分子或离子质量的分子量。
• 化合物的结构阐明和分子式
• 构成分子的不同同位素的同位素丰度

可以看出，质谱提供了大量信息，从任何单个光谱技术中都是不可能的。通过与其他技术（例如GC，LC或FT-IR）的连字符进一步扩展了应用的范围。