Determination of lead, cadmium, arsenic, mercury and copper residues in traditional Chinese medicine (4)

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Atomic fluorescence spectrometry (AFS) is an important branch of atomic spectroscopy.

This section mainly introduces the determination of total arsenic and total mercury residues in traditional Chinese medicine by atomic fluorescence method

(1) Determination method

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(1) Reference substance stock solution: accurately measure appropriate amounts of single element standard solutions of arsenic and mercury, and dilute them with 2% nitric acid solution to make a solution containing 1 ug per 1 ml

(2) Standard curve

Arsenic: Precisely measure 1ml of arsenic standard stock solution (1ug/ml), put it in a 100ml measuring flask, add 1ml of 25% potassium iodide (prepared before use) solution, shake well, add 1ml of 10% ascorbic acid solution (prepared before use) , Shake well, add 10ml of sulfuric acid solution (20→100), add water to the mark, shake well, heat in a water bath at 80°C for 3 minutes (or leave it for 1 hour), take it out, let it cool, and get it

Mercury: Precisely measure 5ml of mercury standard stock solution (1ug/ml), put it in a 50ml measuring bottle, dilute to the mark with water, shake well, accurately draw 1ml, place it in a 100ml measuring bottle, add 20ml of sulfuric acid solution (20→100), Add water to the mark, shake well, and it's ready

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(1) Determination of arsenic: a mixed solution containing 1% sodium borohydride and 0.

(2) Determination of mercury: a mixed solution containing 0.

(2) Matters needing attention

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