The influence of Triton X-100 concentration and time of ultrasonic treatment (frequency 44 kHz, intensity 1.5 W/cm2) on the determination of sodium, potassium, calcium and magnesium in whey processed products by atomic absorption spectroscopy (AAS) was studied. It was shown that the maximum value of the analytical signal is achieved with a mass fraction of Triton X-100 of 5 % and an ultrasonic treatment time of 15 min. The sensitivity of measurements increases from one and a half to two times. Procedures have been developed for determining the content of sodium, potassium, calcium and magnesium in whey and products of its processing by AAS and atomic emission spectroscopy with inductively coupled plasma (AES-ICP). Validation of the results of determination of magnesium and calcium by AAS and AES-ICP was carried out by varying the weight of the sample and standard addition method.