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The effect of matrix interferences on in situ boron isotope analysis by laser ablation multi‐collector inductively coupled plasma mass spectrometry
Author(s) -
Standish Christopher D.,
Chalk Thomas B.,
Babila Tali L.,
Milton J. Andy,
Palmer Martin R.,
Foster Gavin L.
Publication year - 2019
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8432
Subject(s) - chemistry , analytical chemistry (journal) , matrix (chemical analysis) , mass spectrometry , laser ablation , reproducibility , inductively coupled plasma mass spectrometry , boron , interference (communication) , isotope , inductively coupled plasma , natural abundance , isotopes of boron , laser , plasma , environmental chemistry , optics , chromatography , telecommunications , channel (broadcasting) , physics , organic chemistry , quantum mechanics , computer science
Rationale Boron isotope analysis of marine carbonates by laser ablation multi‐collector inductively coupled plasma mass spectrometry (LA‐MC‐ICP‐MS) offers the potential for rapid sample throughput, and the means to examine micron‐scale variations in the δ 11 B signatures of fossil skeletons and shells/tests of marine organisms. Existing studies demonstrate an acceptable level of reproducibility is achievable, but also typically show a level of accuracy outside the limits required by most applications. Here we investigate matrix interference effects as a cause of inaccuracy and imprecision. Methods Analyses were performed on a standard format Thermo Scientific Neptune Plus MC‐ICP mass spectrometer coupled to a New Wave Research 193 nm ArF laser ablation system. The effects of matrix interference on δ 11 B analysis were investigated through analyses of a set of reference materials with differing B/Ca ratios. Three approaches to correct for matrix‐induced effects were trialled: (1) use of matrix‐matched standards, (2) utilisation of the relationship between δ 11 B inaccuracy and 11 B/ 43 Ca, 11 B/ 40 ArCa 4+ or 11 B/Ca interference from three reference materials with known δ 11 B values and varying B/Ca ratios, and (3) direct characterisation of the (sloping) interference itself. Results Matrix interference from scattered Ca ions on 10 B can impede both the accuracy and the reproducibility of δ 11 B analysis by LA‐MC‐ICP‐MS. Based on analyses of two in‐house reference materials, deep sea coral PS69/3181 and inorganic calcite UWC‐1, we find approach 2, following the 11 B/Ca interference relationship, gives the best mean accuracies (within 0.4‰ of solution values) and external reproducibilities (± 0.5‰ 2 SD for PS69/3181). This approach has been applied to analyses of an annual growth cycle of a Siderastrea siderea coral and eight Cibicidoides wuellerstorfi benthic foraminifera. Both coral and foraminifera data match solution MC‐ICP‐MS analyses within reported uncertainties. Conclusions LA‐MC‐ICP‐MS can produce accurate and precise δ 11 B data to a 0.5‰ (2σ) level on <0.3 ng B after correction for Ca interference effects.