Experimental technique to measure mass under high pressure conditions using oscillatory motions of a spring-mass system

Most methods measure changes in the mass of a sample due to adsorption, condensation, or reaction in high-pressure, high-temperature vessels by balancing or directly sensing its weight. This study presents a simple, integrated, mechanical and electromagnetic method to determine mass through the object's inertia. The natural frequency of a sample suspended by a spring was measured using a solenoid and oscilloscope. The effect of the surrounding fluid on the frequency of oscillation was characterized and accounted for in mass determination. The combination of simple mechanical/electromagnetic components and proper calibration provided an average accuracy of 0.25-0.35% for tested masses between 56 g and 106 g. The measuring range in this technique can be changed by fitting the system with springs with different moduli.