Design of Double Sampling Loops System of Inductively Coupled Plasma Mass Spectrometry

Inductively coupled plasma mass spectrometry (ICP-MS) is usually coupled with solution pneumatic nebulizer sampling system, whose detection efficiency is low when measured in series mode. Based on the double-layer six-way multi-way valve, a double sample ring sampling system was designed, which could improve the detection efficiency by changing the connection mode of the sampling system. This system connected with pneumatic nebulizer, one loop was loading sample, the other loop was detecting. The detection time was saved by two-way parallel mode. Determination of different numbers of elements needed different length loop. The correlation coefficients of calibration curves of Sc, Ti, V, Cr, Mn, As, Co, Ni, Cu, Pb, Zn, Cd, Li, Sr, Ba, Co, U, and Th are greater than 0.999, and the precisions (n=5) are less than 5%. 1, 6, 12, 18, and 32 elements were determinted, their detection time was saved 45%, 35%, 27%, 21%, 16%, respectively. The number of elements is fewer, the improvement of the efficiency is higher. Compared with standard method, the limits of detection and sensitivity of this system have no significant difference. The double sampling loops system has no significant memory effect. The two-layer six-way multi-way valve switched manually and owned automation prospect. This system is high efficient, fast and simple, easy to realize automation, and more possibilities to use with other instruments.