(2) synthetic flavors and fragrances analysis and formulation development: vanillin coumarin violet ketone citronella oil, cranberry seed oil, camphor oil, safrole oil, cypress oil, turpentine, castor oil, heterohydric alcohols oils, aromatic hydrocarbons and phenols, etc.
Commonly used Separation and enrichment methods in chemical analysis include:
1. precipitation separation;
2. solvent extraction separation;
3. ion-exchange separation;
4. chromatography separation;
5. volatilization and distillation separation;
Commonly used methods of chemical analysis are:
1. gas chromatography :
Due to the different stationary phases used, they can be divided into two types, those using solid adsorbents as stationary phases are called gas-solid chromatography, and those using monomers coated with a fixative as stationary phases are called gas-liquid chromatography.
According to the separation principle of chromatography, gas chromatography can also be divided into adsorption chromatography and distribution chromatography, in gas-solid chromatography, the stationary phase for the adsorbent, gas-solid chromatography is adsorption chromatography, gas-liquid chromatography belongs to the distribution chromatography.
Gas chromatography has many advantages, but it is mainly used for the determination of volatile substances.
2. Liquid chromatography: liquid as the mobile phase of the chromatographic method.
Liquid chromatography can not be directly from the chromatogram to give the results of the characterization of the unknown, but must be a known standard for the control of qualitative.
Liquid chromatography when there is no pure substance control, qualitative identification is very difficult, then you need to use mass spectrometry, infrared and chemical methods. In addition, most of the metal salts and poor thermal stability of the material can not be analyzed. This shortcoming can be overcome by high performance liquid chromatography.
3. Infrared spectroscopy: based on the relative vibration of atoms within the molecule and molecular rotation and other information to determine the molecular structure of the material and identify compounds analytical methods.
Infrared spectroscopy on the applicability of the sample is quite broad, solid, liquid or gaseous samples can be applied, inorganic, organic, polymer compounds can be detected. In addition, infrared spectroscopy is also characterized by rapid testing, easy operation, good repeatability, high sensitivity, low sample dosage, and simple instrument structure.
4. Electron microscope scanning analysis: applied to metal materials (iron and steel, metallurgy, non-ferrous, machining) and non-metallic materials (chemistry, chemical industry, petroleum, geology and mineralogy, rubber, textile, cement, fiberglass) and other inspection and research. In the field of materials science research, metal materials, ceramic materials, semiconductor materials, chemical materials and other areas of the material's microscopic morphology, organization, composition analysis, all kinds of material morphology and organization observation, material fracture analysis and failure analysis, real-time micro-area composition analysis of the material, elemental quantitative and qualitative compositional analysis, rapid multi-element surface scanning and line scanning distribution measurements, the phase identification of crystals and grains, grain size, shape analysis, crystal, grain orientation measurement.
5. Mass Spectrometry (MS): A method of detecting moving ions (charged atoms, molecules or molecular fragments, molecular ions, isotope ions, fragment ions, rearrangement ions, multi-charge ions, substable ions, negative ions, and ions generated by ion-molecule interactions) by separating them according to their mass-to-charge ratios using electric and magnetic fields.