Iminodiacetic acid type pretreatment column IC-M column

Iminodiacetic acid type pretreatment column IC-M column

Iminodiacetic acid type pretreatment column IC-M column

The filler for IC-M columns (1.0 cc, 2.5 cc) is NH4+type iminodiacetic acid chelating resin.

The main function of IC-M column products is to adsorb, concentrate or remove heavy metal ions in complex sample matrices at pH greater than 4. In this case, the treatment column allows alkali metal and alkaline earth metal ions to pass through. Generally speaking, transition metal ions can be leached through with 0.5 mol/L HNO3.

The "GB 5009.12-2023 Food Safety Standard for the Determination of Lead in Food" released in September 2023, "Graphite Furnace Atomic Absorption Spectroscopy", compared with GB5009.12-2017, has added a pre-treatment method for desalinated samples that uses a column of iminodiacetate chelating resin (1mL, 500mg), which can enrich heavy metal ions such as lead and cadmium, remove interfering metal ions (sodium and potassium ions), and meet the needs of lead content determination in high salt samples.

1. Microwave digestion

Weigh 0.2 g~2 g (accurate to 0.001 g) of solid sample or accurately transfer 0.50 mL~3.00 mL of liquid sample into a microwave digestion tank. The sample containing ethanol or carbon dioxide is first heated at low temperature on an electric heating plate to remove ethanol or carbon dioxide, and then 5 mL~10 mL of nitric acid is added (the amount of nitric acid used can be adjusted according to the sample weighing and properties). The sample is digested according to the microwave digestion heating program in Table 1 (which can be adjusted reasonably according to the instrument model). After cooling, the digestion tank is taken out and the sample is acidified to near dryness on an electric heating plate at 140 ° C~160 ° C. After cooling the digestion tank, wash it 2-3 times with sodium acetate solution (2 mol/L), combine the washing solutions in a 25 mL volumetric flask, and dilute to the mark with sodium acetate solution (2 mol/L). Mix well and set aside (pH 4.5-6.5 of the solution after dilution). Simultaneously conduct a reagent blank test.

(1) Column pretreatment: Remove the solid-phase extraction column, open the lower end plug, and drain the storage solution (20% ethanol) inside the column;

(2) Activation: Draw 10 mL of nitric acid solution (1+99) through the column at a flow rate of 5 mL/min, and then pass 5 mL of water and 5 mL of ammonium acetate solution (1 mol/L) through the column at a flow rate of 5 mL/min, respectively;

(3) Sample loading: Take 25 mL of reagent blank solution and 1 prepared sample solution separately, and pass them through the column at a flow rate of 5 mL/min;

(4) Rinsing: Wash the column with 5 mL of ammonium acetate solution (1 mol/L), and then wash the ammonium acetate solution (1 mol/L) twice with 10 mL of water;

(5) Elution: Wash with 10 mL nitric acid solution (1+99), collect the eluent, and prepare for testing.