Matrix effects in laser ablation molecular isotopic spectrometry

Reduction of spectral interferences and noise effects in laser ablation molecular isotopic spectrometry with partial least square regression – a computer simulation study

“…For the purpose of the present study, the corrected Kurucz database [28] was adequate for spectra simulation. is an appropriate choice for isotopic analysis of 13 C because the line positions from the 13 C 12 C isotopologue is red shifted from the more abundant 12 C 12 C. As the bandheads of the C 2 d 3 Π ga 3 Π u system degrade to blue, the red-shifted 13 C 12 C (1-0) bandhead appears in front of and not buried inside the decaying part of the dominant 12 C 2 bandhead. However, other rovibronic structures from the Swan band, in particular those from 0-0, 1-1 and 9-8 [21], of the dominant 11 12 C 2 isotopologue emit in close wavelength proximity to the bandhead of 13…”

“…The PLS algorithm used in this study was a PLS1 type and is similar to the one previously described [2,10,11]. A library of standard spectra from eleven (unless otherwise specified) standards with 13 C abundances evenly distributed between 0% and 2% was complied. For each standard, there were ten simulated spectra, and each spectrum comprised accumulated signals from 100 laser shots (unless otherwise specified).…”

“…The boron figures quoted above were all from boron samples with natural isotopic 5 abundance [2,3,[7][8][9][10] (the minor isotope, 10 B is ~ 19.9% [12]) whereas the atom percentages of 2 H in the OH/OD LAMIS study [11] ranged from 6% to 97%. There are many isotopes with natural abundances around or less than 1% (e.g., 13 C ~1.1%, 15 N ~0.4%, 18 O ~0.2%, 235 U ~0.7% [12]). One objective of the present study is to understand the fundamental limits of analytical accuracy and precision attainable by LAMIS when the minor isotopes are at abundances ~1%.…”

“…As many samples contain other co-existing elements besides the element(s) of interest, spectral interferences could potentially limit the accuracy and precision of LAMIS. Brown et al [13] recently showed that, for isotopic analysis of B using the BO molecular emission in a LaBO 3 sample, La atomic lines strongly overlapped the BO molecular band and thus compromised the analysis. Even for a highly purified sample that contains only the analyte, because atomic emission sometimes overlaps with molecular emission in both the temporal and wavelength domains, the ionic or neutral atomic emission from the analyte itself is a potential source of spectral interference in LAMIS.…”

“…In addition to understanding how different factors affect the analytical performance of LAMIS, new ways to minimize their impacts were also formulated and demonstrated. The C 2 Swan band (d 3 Π ga 3 Π u ) with  = +1 was selected as the representative system, as the natural abundance of 13 C is about 1.1%. Further, the C 2 Swan band is one of the strongest molecular bands present when an organic material is ablated [17,18], and therefore, has been utilized for isotopic analysis of carbon [19][20][21].…”