What instruments will be used for sample pretreatment

In the process of the experiment, sample pretreatment is a very important part for the analysis and detection experimenter, which occupies the majority of the whole analysis process. Similarly, the error of experimental analysis also comes from sample pretreatment, which is not only related to the analysis of technicians, but also to the instrument. Today, I'd like to share with you some commonly used instruments for sample pretreatment.

1. Gas chromatography mass spectrometry

All gas chromatographs use capillary column (packed column is not allowed). The sample entering the gas chromatography must be able to vaporize completely within the operating temperature range of the chromatographic column.

2. UV Vis absorption spectrometer

(1) The concentration of the sample solution must be appropriate, and it must be clear and transparent without bubbles or suspended substances;

(2) 2 g and 2 ml respectively.

3. Gas chromatograph

The sample that can be directly analyzed should be volatile and thermally stable. The boiling point should not exceed 300 ℃ generally. If the sample can not be directly injected, it needs to be pretreated.

4. Liquid chromatograph

If the sample should be dried, it is better to provide the structure of the component to be tested; for the complex sample, as far as possible, provide what other components may be in the sample.

5. Element analyzer

(1) Fill in the registration form of sample submission for element analysis, and provide molecular formula and theoretical content of elements or other relevant information as far as possible;

(2) The sample must be a uniform solid particle or liquid without adsorbed water and purified. For example, impure samples (including adsorbed water, organic solvents, inorganic salts or other impurities) will affect the analysis results and make the test values inconsistent with the calculated values;

(3) The sample should be in sufficient quantity to meet the linearity and sensitivity of the method and instrument.

6. Ion chromatograph

The sample can be dissolved in water, or dilute acid or alkali, and the acid and alkali used cannot contain ions to be measured. For the compounds that contain elements to be determined but exist in non-ionic state in water, acid and alkali solutions, corresponding sample pretreatment is needed.

The liquid sample must be concentrated and dried before sample pretreatment. The sample to be analyzed must be a solid with stable physical and chemical properties under high energy electron bombardment, which is non decomposition, non explosion, non volatilization, non radioactivity and non magnetism. When sending samples, it is better to indicate what elements the sample may contain.