Cold Plasma: way to improve repeatability of metal analysis in sub-microliter volumes?
|Year of publication||2019|
|MU Faculty or unit|
|Description||Substrate-assisted laser desorption inductively coupled plasma mass spectrometry (SALD ICP MS) allows fast and direct determination of metals in sub-microliter volumes applied onto a polymer substrate in the form of dried droplets. In certain cases, however, RSD values range up to 30 % due to the formation of inhomogeneous dried droplets. The addition of a suitable internal standard and incorporation of Diffuse Coplanar Surface Barrier Discharge (DCSBD) for surface treatment of substrate improves the repeatability of the determination considerably. DCSBD treatment of substrate surface allows increasing its wettability, which results in the formation of homogenous dried droplets. However, a disadvantage of this treatment is the occurrence of the “aging” effect,” i.e., a gradual regression of the modified physical-chemical properties of the substrate surface to an original state. The experiments have shown a significant change in the wettability of the substrates with DCSBD treatment. The repeatability of the determination is considerably better for the samples applied to the substrates in the shorter time interval from DCSBD treatment. But the type of the substrate, its treatment and aging effect as well as sample composition influence significantly repeatability of the determination.|