TY - JOUR
T1 - Chalcophile chemistry for enhanced detection of copper in its compounds and minerals
AU - Mehta, Rohan
AU - Zheng, Zhaoyu
AU - Pavlov, Julius
AU - Attygalle, Athula B.
N1 - Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/7/15
Y1 - 2019/7/15
N2 - Samples of elemental copper, upon laser irradiation under negative-ion LDI-MS conditions, do not generate noticeable signals for copper-bearing gaseous ions. In contrast, a several thousand-fold enhancement of the generated ion current was observed when freshly made mixtures of copper and sulfur powders were laser-ablated. Time-of-flight mass spectra recorded showed a range of peaks with m/z ratios extending to over m/z 8000, indicating the formation in situ of an array of Cu–S ion clusters by a chemical reaction that takes place between the two elements upon laser irradiation. Evidently, sulfur acts as a potent reactive matrix and generates at least three distinguishable series of ion clusters: Cu1Sx− (x = 2, 3, 4…), Cu2Sy−[rad] (y = 3, 4, 5…), and Cu3Sz− (z = 3, 4, 5…). Laser ablation of CuS alone did not produce signals beyond m/z 600. Some of the high-mass ions formed in this manner were isobaric; consequently, composite peaks were observed under low-resolution MS conditions. Under high-resolution conditions, however, we were able to separate and determine the composition of some isobaric mixtures. For example, the peak recorded at m/z 287 was resolved to two peaks that represented primarily the 63Cu265Cu32S3− and 63Cu32S7− ions. Intriguingly, the spectra recorded from many copper-containing minerals mixed with sulfur were remarkably similar to those acquired from copper-and-sulfur mixtures, which demonstrated that elemental sulfur has the ability to extract chemically bound copper even from its compounds, and form gas-phase Cu–S clusters of varying composition.
AB - Samples of elemental copper, upon laser irradiation under negative-ion LDI-MS conditions, do not generate noticeable signals for copper-bearing gaseous ions. In contrast, a several thousand-fold enhancement of the generated ion current was observed when freshly made mixtures of copper and sulfur powders were laser-ablated. Time-of-flight mass spectra recorded showed a range of peaks with m/z ratios extending to over m/z 8000, indicating the formation in situ of an array of Cu–S ion clusters by a chemical reaction that takes place between the two elements upon laser irradiation. Evidently, sulfur acts as a potent reactive matrix and generates at least three distinguishable series of ion clusters: Cu1Sx− (x = 2, 3, 4…), Cu2Sy−[rad] (y = 3, 4, 5…), and Cu3Sz− (z = 3, 4, 5…). Laser ablation of CuS alone did not produce signals beyond m/z 600. Some of the high-mass ions formed in this manner were isobaric; consequently, composite peaks were observed under low-resolution MS conditions. Under high-resolution conditions, however, we were able to separate and determine the composition of some isobaric mixtures. For example, the peak recorded at m/z 287 was resolved to two peaks that represented primarily the 63Cu265Cu32S3− and 63Cu32S7− ions. Intriguingly, the spectra recorded from many copper-containing minerals mixed with sulfur were remarkably similar to those acquired from copper-and-sulfur mixtures, which demonstrated that elemental sulfur has the ability to extract chemically bound copper even from its compounds, and form gas-phase Cu–S clusters of varying composition.
KW - Chalcophiles
KW - Copper sulfur
KW - Gas-phase clusters
KW - Laser desorption/ionization
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U2 - 10.1016/j.poly.2019.04.019
DO - 10.1016/j.poly.2019.04.019
M3 - Article
AN - SCOPUS:85065099266
SN - 0277-5387
VL - 167
SP - 127
EP - 136
JO - Polyhedron
JF - Polyhedron
ER -