How Does HMI Work?
The HMI hardware consists of a modified torch mounting and the insertion of a make up gas line between the spray chamber and torch. Nebulizer gas flow is reduced to decrease the efficiency of the nebulizer, and the make up, or “dilution” gas, is increased so the total carrier gas flow into the torch is kept constant. The sample solution aspirated can be 1% or higher TDS, but since the quantity of aerosol production is greatly decreased, the plasma is not overloaded by the extra sample matrix. Reduced sample aerosol transport also means that a reduced amount of solvent and water vapor is carried to the plasma. With less water to decompose, the plasma is hotter and therefore more robust. This increased robustness is key to improving the ability of ICP-MS to run very high and variable matrix samples routinely and accurately. Analytical Benefits of HMI Figure 1. Signal suppression in undiluted NASS-5 Figure 1 shows the % recovery of a 10ppb multi-element spike in undiluted NASS-5 seawater
