Distribution mapping of metal-based nanoparticles by Laser-Induced Breakdown Spectroscopy
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| Year of publication | 2015 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | Distribution mapping of nanoparticles (NPs) and quantum dots (QDs) using LIBS was optimized in order to achieve best spatial resolution and lowest detection limits. The dependence of the LIBS signal intensity on the volume and concentration of the injected NPs onto different substrates was investigated in detail. Modified ablation system New Wave UP-266 MACRO with Nd:YAG laser operating at 4th harmonic wavelength of 266 nm was equipped with chromatographic paper or polystyrene microplates holder. Software-controlled movement in x,y direction enabled scanning of the sample surface. In double pulse orthogonal configuration the second re-heating laser pulse with fundamental wavelength of 1064 nm (Quantel, Brilliant) was delivered to the primary plasma plume using two mirrors in the periscope arrangement allowing precise laser beam positioning. Samples were measured in the air at atmospheric pressure. Single pulse LIBS in 2D mapping mode was investigated for detection of silver (10 nm diameter) and gold (5 nm diameter) NPs. Detection limits (LOD) after injection solution onto polystyrene plate for Ag and Au NPs were found 0.01 and 0.3 ng per µl resp. LIBS in double pulse configuration was developed for the distribution mapping of Cd after injection of CdS QDs onto the carrier material. The best signal to noise (S/N) ratio and spatial resolution were achieved using the chromatographic paper as a carrier material and emission line Cd (I) 508.58 nm. LOD of Cd at pmol levels were obtained. The observed absolute LOD for Cd in CdTe QDs conjugates with metallothionein (MT) in one spot was 3 ng. The immunoanalysis in combination with LIBS was also investigated and Cd spatial distribution in sandwich immunoassay was detected. Due to the immediate signal response, relatively simply instrumentation and automation LIBS offers promising and fast alternative to other techniques in NPs detection and also in immunoassay (especially with high repetition rate laser and detector). |
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