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水野直美律師 guest 水野直美律師 2021/06/17 10:58

研究對象與方法

由於有機化合物常以混合物的形式存在，因此有許多方式可以分離出高純度的物質。傳統的方式包括蒸餾、結晶及溶劑提取，現在的方式則包括色譜法，包括高效液相色譜法或是氣相色譜法。

有機物質的傳統分析方法是是透過許多化學測試來進行，這稱為「濕法」，但已被用光譜學或是電腦分析的方法所取代[16]。

有機化學的研究對象主要就是「如何形成碳碳鍵」。有機化學是碳的化學，簡而言之就是研究如何構建碳原子的結構。因為對人們有用處的有機分子一般是大而複雜的，而人們能隨意支配和輕易獲得的原料往往是小而簡單的。有機化學的研究方法就是根據研究需要，利用結構和機構來設計預測一個變化，通過實驗和分析檢測來驗證結果，並對設計進行反饋修正。

以下是一些常用的分析方式：

核磁共振光譜法是最常用的技術，可以知道完整的分子結構資訊，透過關聯性磁振頻譜甚至還可以知道立體化學的一些資訊。有機化學的主要元素碳和氫都有自然存在，可以用核磁共振檢測的同位素，分別是 H 1 {\displaystyle {\ce {^1H}}} {\displaystyle {\ce {^1H}}}及 C 13 {\displaystyle {\ce {^13C}}} {\displaystyle {\ce {^13C}}}。
元素分析：一可以檢測分子中組成原子的破壞性檢測方式，已被質譜法取代。
質譜法可以檢測化合物的分子量，藉由質譜分析也可以看出其結構。高解析度的質譜法可以看出分子準確的分子量，已可以取代元素分析。早期質譜法只能用在一些有揮發性的天然物質中，但先進的離子化技術已經可以檢測任何有機化合物的質譜。
晶體學也是一種可以得到分子結構的方法，但其前提是可以得到物質的單晶，且此單晶可以反映待測物的結構。

傳統的色譜法方式，像是紅外光譜學、旋光及紫外－可見分光光度法可以提供大略的資訊，在分析一些特定的化合物時仍有使用。



Characterization

Since organic compounds often exist as mixtures, a variety of techniques have also been developed to assess purity; chromatography techniques are especially important for this application, and include HPLC and gas chromatography. Traditional methods of separation include distillation, crystallization, evaporation, magnetic separation and solvent extraction.

Organic compounds were traditionally characterized by a variety of chemical tests, called "wet methods", but such tests have been largely displaced by spectroscopic or other computer-intensive methods of analysis.[17] Listed in approximate order of utility, the chief analytical methods are:

Nuclear magnetic resonance (NMR) spectroscopy is the most commonly used technique, often permitting the complete assignment of atom connectivity and even stereochemistry using correlation spectroscopy. The principal constituent atoms of organic chemistry – hydrogen and carbon – exist naturally with NMR-responsive isotopes, respectively 1H and 13C.
Elemental analysis: A destructive method used to determine the elemental composition of a molecule. See also mass spectrometry, below.
Mass spectrometry indicates the molecular weight of a compound and, from the fragmentation patterns, its structure. High-resolution mass spectrometry can usually identify the exact formula of a compound and is used in place of elemental analysis. In former times, mass spectrometry was restricted to neutral molecules exhibiting some volatility, but advanced ionization techniques allow one to obtain the "mass spec" of virtually any organic compound.
Crystallography can be useful for determining molecular geometry when a single crystal of the material is available. Highly efficient hardware and software allows a structure to be determined within hours of obtaining a suitable crystal.

Traditional spectroscopic methods such as infrared spectroscopy, optical rotation, and UV/VIS spectroscopy provide relatively nonspecific structural information but remain in use for specific applications. Refractive index and density can also be important for substance identification.