Simultaneous determination of 12 elements in biological samples using microwave digestion and inductively coupled plasma-optical emission spectrometry

Given the particularity of biological samples, this study employed microwave digestion and inductively coupled plasma-optical emission spectrometry (ICP-OES) for the simultaneous determination of 12 elements in biological samples, including aluminum (Al), ferrum (Fe), magnesium (Mg), calcium (Ca), sodium (Na), potassium (K), manganese (Mn), phosphorus (P), titanium (Ti), barium (Ba), strontium (Sr), and zinc (Zn). By optimizing the pretreatment conditions of microwave digestion samples, this study selected the mixed reagent of reverse aqua regia (10 mL) and hydrogen peroxide (1 mL) as the digestion reagent, and an appropriate experimental procedure for the microwave digestion system to ensure complete decomposition of samples. Moreover, this study selected the optimal plasma excitation conditions, analytical spectral lines of elements, and background subtraction position to ensure high determination sensitivity of elements and interference-free spectral lines. This study plotted the calibration curve with the national primary reference materials for biological components as the calibration series, making the calibration series consistent with the sample matrix as much as possible. The simultaneous determination method had a total dilution multiple of 100, eliminating the interference of the matrix effect. The results show that this method had a detection limit of (0.04~4.93)×10^-6 and a relative standard deviation (RSD) of 1.41%~5.13%, showing high precision. As verified by the national primary reference materials, this method had a relative error (RE) within ±10% and determined values consistent with standard values. Therefore, this method is accurate and reliable, meeting the analysis requirements of biological samples.