The Laboratorio Subterráneo de Canfranc (LSC) is the Spanish national hub for low radioactivity techniques and the associated scientific and technological applications. The concentration of the airborne radon is a major component of the radioactive budget in the neighborhood of the detectors. The LSC hosts a Radon Abatement System, which delivers a radon suppressed air with 1.1±0.2 mBq/m3 of 222Rn. The radon content in the air is continuously monitored with an Electrostatic Radon Monitor. Measurements with the double beta decay demonstrators NEXT-NEW and CROSS and the gamma HPGe detectors show the important reduction of the radioactive background due to the purified air in the vicinity of the detectors. We also discuss the use of this facility in the LSC current program which includes NEXT-100, low background biology experiments and radiopure copper electroformation equipment placed in the radon-free clean room.
Inductively
coupled plasma–mass spectrometry (ICP–MS)
has been widely used in Life Sciences for the absolute quantification
of biomolecules without specific standards, assuming the same response
for generic compounds including complex biomolecules. However, contradictory
results have been published on this regard. We present the first critical
statistical comparison of the ICP–MS response factors obtained
for 14 different relevant S-containing biomolecules (three peptides,
four proteins, one amino acid, two cofactors, three polyethylene glycol
(PEG) derivatives, and sulfate standard), covering a wide range of
hydrophobicities and molecular sizes. Two regular flow nebulizers
and a total consumption nebulizer (TCN) were tested. ICP–MS
response factors were determined though calibration curves, and isotope
dilution analysis was used to normalize the results. No statistical
differences have been found for low-molecular-weight biocompounds,
PEGs, and nonhydrophobic peptides using any of the nebulizers tested.
Interestingly, while statistical differences were still found negligible
(96–104%) for the proteins and hydrophobic peptide using the
TCN, significantly lower response factors (87–40%) were obtained
using regular flow nebulizers. Such differential behavior seems to
be related mostly to hydrophobicity and partially to the molecular
weight. Findings were validated using IDA in intact and digested bovine
serum albumin solutions using the TCN (98 and 100%, respectively)
and the concentric nebulizer (73 and 97%, respectively). Additionally,
in the case of a phosphoprotein, results were corroborated using the
P trace in parallel to the S trace used along the manuscript. This
work seems to suggest that ICP–MS operated with regular nebulizers
can offer absolute quantification using generic standards for most
biomolecules except proteins and hydrophobic peptides.
The synthesis of new multifunctional engineered nanoparticles (ENPs) constitutes nowadays a research topic of increasing importance in nano(bio)technology. Such ENPs can be synthesized out of a large variety of different...
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