Advantages and disadvantages of chloroform-methanol extraction method

Advantages of chloroform-methanol extraction method: good selectivity and low energy consumption.

Disadvantages:

The biggest disadvantage of (1) extraction method in determining fat is that it takes too long. If the sample can be refluxed 1~2 times, then soaked in the solvent overnight and extracted again the next day, the extraction time can be obviously shortened.

(2) If there are many experimental samples, YG-Ⅱ grease analyzer with large capacity can be used to determine the fat content, and the temperature can be controlled at about 70℃, and the extraction can be completed in 8 hours.

Selection of extractant

The extractant should be selected according to the nature of the extract. The solubility of the tested components should be the maximum, and the solubility of impurities should be the minimum, and the extraction effect should follow the principle of similar solubility. Generally, the less polar components (such as organochlorine pesticides) are extracted with less polar solvents (such as n-hexane and petroleum ether), and the more polar components (such as aflatoxin B 1) are extracted with more polar solvents (such as mixed solution of methanol and water). The boiling point of the selected solvent should be appropriate, too low is volatile, too high is difficult to concentrate.