TY - JOUR
T1 - Effects of molecular weight and cationization agent on the sensitivity of Bi cluster secondary ion mass spectrometry
AU - Fujii, Makiko
AU - Shishido, Rie
AU - Satoh, Takaya
AU - Suzuki, Shigeru
AU - Matsuo, Jiro
N1 - Publisher Copyright:
Copyright © 2016 John Wiley & Sons, Ltd.
PY - 2016/7/30
Y1 - 2016/7/30
N2 - Rationale: Bi cluster secondary ion mass spectrometry (SIMS) is one of the most promising tools for precise analysis of synthetic polymers. However, the sensitivity in the high-mass region is still insufficient compared with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Accordingly, the effects of metal assistance (cationization agents) were investigated in this study. Methods: To investigate the effects caused by varying the ionization agent, three different polyethylene glycol (PEG) samples were prepared, one with an Ag-deposited film, and two others mixed with Ag and Na, respectively. The measurements were performed by using a commercial Bi cluster SIMS and MALDI-TOFMS systems. The mass spectrum obtained with MALDI-TOFMS was used as a reference molecular weight distribution to evaluate the effects of molecular weight and primary ion species (Bi+, Bi3 +, Bi3 2 +) on the sensitivity of Bi cluster SIMS. Results: The intensity of each secondary ion was the highest in Bi3 2 + irradiation, and the lowest in Bi+ irradiation. Regarding the cationization agents, the secondary ion yield was the highest for the sample mixed with Ag, while the degree of decay of sensitivity along with the increase in molecular weight was the smallest for the sample mixed with Na. Conclusions: It was suggested that the cationization mechanism consists of pre-formed ionization and gas-phase ionization processes. The sensitivity of Bi cluster SIMS decreases to approximately one-fiftieth in every 1000 u. These results might help in understanding the mechanism of cationization and further enhancement of secondary ion yields of polymers.
AB - Rationale: Bi cluster secondary ion mass spectrometry (SIMS) is one of the most promising tools for precise analysis of synthetic polymers. However, the sensitivity in the high-mass region is still insufficient compared with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). Accordingly, the effects of metal assistance (cationization agents) were investigated in this study. Methods: To investigate the effects caused by varying the ionization agent, three different polyethylene glycol (PEG) samples were prepared, one with an Ag-deposited film, and two others mixed with Ag and Na, respectively. The measurements were performed by using a commercial Bi cluster SIMS and MALDI-TOFMS systems. The mass spectrum obtained with MALDI-TOFMS was used as a reference molecular weight distribution to evaluate the effects of molecular weight and primary ion species (Bi+, Bi3 +, Bi3 2 +) on the sensitivity of Bi cluster SIMS. Results: The intensity of each secondary ion was the highest in Bi3 2 + irradiation, and the lowest in Bi+ irradiation. Regarding the cationization agents, the secondary ion yield was the highest for the sample mixed with Ag, while the degree of decay of sensitivity along with the increase in molecular weight was the smallest for the sample mixed with Na. Conclusions: It was suggested that the cationization mechanism consists of pre-formed ionization and gas-phase ionization processes. The sensitivity of Bi cluster SIMS decreases to approximately one-fiftieth in every 1000 u. These results might help in understanding the mechanism of cationization and further enhancement of secondary ion yields of polymers.
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U2 - 10.1002/rcm.7614
DO - 10.1002/rcm.7614
M3 - Article
AN - SCOPUS:85015936680
SN - 0951-4198
VL - 30
SP - 1722
EP - 1726
JO - Rapid Communications in Mass Spectrometry
JF - Rapid Communications in Mass Spectrometry
IS - 14
ER -