Evaluation of Matrix Effects in a Pulsed Electrolyte Cathode Atmospheric Pressure Discharge Source for Atomic Emission

Abstract

In sample measurements, matrix effects are unavoidable. The matrix effects are one of the main factors affecting the accuracy of the pulsed electrolyte cathode atmospheric pressure discharge detection system. The stability of sodium, potassium, and magnesium, under optimized parameters is measured; the relative standard deviation of spectral intensity is found to be no more than 2%; and the relative standard deviation of background intensity is less than 2%. The matrix effects on the elements potassium, sodium, and magnesium were studied, and the experiments showed that high concentrations of sodium and potassium interfere with each other. A concentration of 200 mg L⁻¹ K⁺ affected the sodium signal with an enhancement of more than 120%; and the K⁺ intensity increased 20% in the presence of a high concentration of 200 mL⁻¹ Na⁺. In high concentrations of sodium or potassium, the elemental signal for magnesium enhancement was approximately 8%. Sodium, potassium, and magnesium were quantitatively determined using a mixed calibration sample. When sodium, potassium, and magnesium are present at low concentrations in solution, there were no obvious matrix effects. The sodium, potassium, and magnesium in the calibration samples are quantitatively determined. The relative error and precision are less than 3%, and the recoveries are less than 105%. The detection limits for sodium, potassium, and magnesium were found to be 2.1, 3.4, and 92.6 µg L⁻¹, respectively.