To begin, pipette 2.5 milliliters of the filtered digested food samples into 25-milliliter glass volumetric flasks. Make up the volume of the flask with ultrapure water. Transfer the diluted samples into 15-milliliter plastic tubes and place them in appropriate positions in the autosampler.
Next, switch on the ventilation and the chiller of the ICP-MS instrument. Program the software to allow for continuous flow of the rinsing solution from the autosampler to the instrument without pulsating. Open the argon and helium gas cylinders to supply the instrument.
Then, start up the instrument and calibrate it with the tuning solution. After determining the approximate element concentrations with a semi-quantitative analysis, create a method in the software for a quantitative elemental analysis. Choose the elements to be analyzed and decide on the number and concentrations of the solutions of standard needed to construct a calibration curve.
To prepare the solutions of standard with automatic pipettes, add the required volumes of multi-element standard solution into a 25-milliliter glass volumetric flask. Top off each flask with 1%nitric acid. Prepare a calibration blank with only 1%nitric acid solution.
Perform the quantitative analysis of the selected elements in samples based on the calibration curve methodology. Once the measurements are complete, switch off the plasma. Close the argon and helium gas supplies.
Then, switch off the ICP-MS chiller and the ventilation system. The linear concentration ranges for all measured elements were in the range from one to 50 micrograms per liter. The recovery percentage for all analytes measured in all four food samples was in the range of 80%to 120%indicative of the accuracy of the analytical method.
