Application of external customized waveforms to a commercial quadrupole ion trap

AbstractThe Finnigan LCQ quadrupole ion trap has recently become part of the repertoire of instruments for many analytical laboratories. The LCQ commercial design, while employing complex waveforms to manipulate ions, does not allow the application of many state-of-the-art user-defined waveforms that enable one to perform other complex ion manipulations. The work presented here describes the simple modifications made to the LCQ electronics to allow the application of external customized waveforms. Results show that externally generated waveforms can be applied to the endcap electrodes while still working within the context of the commercial software and hardware. Double resonance, multiple ion isolation, and multiple ion excitation experiments are demonstrated to reveal the effectiveness of these modifications

Rod-shape theranostic nanoparticles facilitate antiretroviral drug biodistribution and activity in human immunodeficiency virus susceptible cells and tissues

Human immunodeficiency virus theranostics facilitates the development of long acting (LA) antiretroviral drugs (ARVs) by defining drug-particle cell depots. Optimal drug formulations are made possible based on precise particle composition, structure, shape and size. Through the creation of rod-shaped particles of defined sizes reflective of native LA drugs, theranostic probes can be deployed to measure particle-cell and tissue biodistribution, antiretroviral activities and drug retention. Methods: Herein, we created multimodal rilpivirine (RPV) 177lutetium labeled bismuth sulfide nanorods (177LuBSNRs) then evaluated their structure, morphology, configuration, chemical composition, biological responses and adverse reactions. Particle biodistribution was analyzed by single photon emission computed tomography (SPECT/CT) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging. Results: Nanoformulated RPV and BSNRs-RPV particles showed comparable physicochemical and cell biological properties. Drug-particle pharmacokinetics (PK) and biodistribution in lymphoid tissue macrophages proved equivalent, one with the other. Rapid particle uptake and tissue distribution were observed, without adverse reactions, in primary blood-derived and tissue macrophages. The latter was seen within the marginal zones of spleen. Conclusions: These data, taken together, support the use of 177LuBSNRs as theranostic probes as a rapid assessment tool for PK LA ARV measurements

Multiplexed Imaging of Nanoparticles in Tissues

To more fully understand the biodistributions and potential toxicity of nanoparticles (NPs) that are released into the environment, it is essential to monitor the spatial distributions of NPs in vivo. To this end CHM scientists have developed an approach based on laser desorption/ionization mass spectrometry (LDI-MS) to image NPs in tissues. Because MS is used as the readout for this imaging approach, multiple NPs can be imaged simultaneously, which facilitates the side-by-side comparison of different NP types. Results indicate that NPs can remain intact in animals and that biodistribution information can be directly obtained

Quantum Dot Stability in Cells is Size Dependent

Quantum dots (QDs) are highly fluorescent and photostable, making them excellent tools for imaging. When using these QDs in cells and animals, however, intracellular biothiols can degrade the QD monolayer compromising function. CHM scientists have developed a label-free method to quantify the intracellular stability of monolayers on QD surfaces that couples laser desorption/ionization mass spectrometry (LDI-MS) with inductively coupled plasma mass spectrometry (ICP-MS). Using this new approach they have demonstrated that QD monolayer stability is correlated with both QD particle size and monolayer structure, with proper choice of both particle size and ligand structure required for intracellular stability

Nanoparticle-Based Anticounterfeiting

We have developed an anti-counterfeiting strategy based on the ionization of ligands from gold nanoparticles. In practice, the particles were inkjet printed onto surfaces, and the "mass barcodes" arising from different ligands was read off using laser desorption mass spectrometry (LDI-MS). This method provides rapid and efficient authentication of materials, with applications in pharmaceuticals, currency, and other areas where counterfeiting is common

Efecto de la configuración electrónica en la energía de disociación de complejos M(EN-Pyr2)2+

Se realizó un estudio sistemático de la energía de disociación de ciertos complejos metálicos con metales transición usando un espectrómetro de masas, el cual estaba equipado con una fuente de ionización por electrovaporización (ESI). Se sintetizaron complejos metálicos modelo, usando los metales de transición de Mn+2 hasta Zn+2, y el ligando EN-Pyr2 (Dos piridinas unidas a etilenamina). Estos complejos fueron ionizados usando ESI, luego se aisló el pico de interés, yposteriormente se disoció, utilizando disociación inducida por colisión (CID) para generar los iones producto. La energía relativa de disociación fue determinada mediante el método de energía variable CID. Se observaron diferencias en laenergía relativa de disociación dependiendo del ión metálico, de igual manera se observo que la energía de disociación disminuía a medida que el radio iónico se hacia menor (i.e. Mn+2Zn+2). excepto con Cu+2 al parecer, debido a que este último se reduce fácilmente