Pulsed laser ablation (LA) devices in laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) imaging have become very advanced, delivering laser pulses with high temporal accuracy and stable energy density. However, unintentional imaging artifacts may be generated in 2D element maps when the LA repetition rate and the data acquisition parameters of ICPMS instruments with a sequential mass spectrometer (i.e., quadrupole filter or sector-field mass spectrometer) are desynchronized. This may potentially lead to interference patterns, visible as ripples in elemental images, and thus, compromised image quality. This paper describes the background of aliasing in continuous scanning mode through simulation experiments and ways to modulate the effect. The existence of this image degradation source is demonstrated experimentally via real-life imaging of a homogeneous glass standard.
COBISS.SI-ID: 6321178
This work describes the aliasing effects induced by undersampling the high-frequency signal patterns generated by a laser ablation-inductively coupled plasma-mass spectrometer equipped with a low-dispersion ablation cell and sequential mass analyzer. By characterizing the width of the signal peak generated froma single shot on the sample, critical experimental parameters, such as the laser repetition rate and detector cycle timings for the in- dividual nuclides can bematched so as to avoid these imaging artifacts (spectral skew) induced by an insufficient sampling rate. By increasing the laser repetition rate by a factor 2–3, masses at the end of themass scan can be sampled at higher sensitivity. Furthermore, the dwell times can be redistributed over the nuclides of interest based on the signal-to-noise ratio to increase the image contrast.
COBISS.SI-ID: 6295066
Highly homogeneous multi-element gelatin calibration standards were fabricated for quantitative LA-ICP-MS bioimaging. Heterogeneity issues caused by the so-called “coffee-stain” and/or “Marangoni” effects were found to be element-dependent but could be circumvented by careful selection of drying/setting con- ditions. A micro-homogeneity test was developed for certification of the standards.
COBISS.SI-ID: 6223130