Lomax-Vogt Madeleine, Carter Lucas M, Wielinski Jonas, Kutuzov Stanislav, Lowry Gregory V, Sullivan Ryan, Gabrielli Paolo, Olesik John W
Trace Element Research Laboratory, School of Earth Sciences, The Ohio State University Columbus OH 43210 USA
Department of Chemistry and Biochemistry, The Ohio State University Columbus OH 43210 USA.
J Anal At Spectrom. 2025 Feb 5;40(3):848-859. doi: 10.1039/d4ja00425f. eCollection 2025 Mar 5.
While spICP-MS has been used mainly to measure nanoparticles, it can also be used to measure microparticles. The transport efficiency of nanoparticles is typically independent of their size. However, the transport efficiency of microparticles can be particle size (mass) dependent as well as being dependent on the sample uptake rate and sample introduction system used. To measure both nanoparticles and microparticles a very large linear dynamic range (where signal intensity is linearly proportional to the measured analyte(s) mass within a very short measurement time (∼300 to 500 µs, the width of signals produced by an individual particle)) is needed. Deviations from linearity could occur due to incomplete particle vaporization or from signals that are beyond the instrument's ion detection system linear dynamic range. To characterize and determine the cause of nonlinearity we measured sets of nearly monodisperse engineered SiO particles with diameters from 500 to 5000 nm and Au particles with diameters from 60 to 1500 nm. We found that by reducing the sensitivity (up to a factor of 269×) the upper end of the linear dynamic range, in particle size that produced signal intensities that were linearly proportional to the particle (analyte) mass, could be greatly extended. Not surprisingly, reducing the sensitivity increased the minimum size detectable particle. The results are consistent with SiO particles as large as 5000 nm being completely vaporized in the ICP.
虽然单颗粒电感耦合等离子体质谱（spICP-MS）主要用于测量纳米颗粒，但它也可用于测量微米颗粒。纳米颗粒的传输效率通常与其尺寸无关。然而，微米颗粒的传输效率可能既取决于颗粒大小（质量），也取决于样品摄取率和所使用的样品引入系统。为了同时测量纳米颗粒和微米颗粒，需要非常大的线性动态范围（在非常短的测量时间内（约300至500微秒，即单个颗粒产生的信号宽度），信号强度与所测分析物质量呈线性比例关系）。由于颗粒不完全汽化或信号超出仪器离子检测系统的线性动态范围，可能会出现线性偏差。为了表征和确定非线性的原因，我们测量了直径从500到5000纳米的近单分散工程化二氧化硅颗粒组以及直径从60到1500纳米的金颗粒组。我们发现，通过降低灵敏度（高达269倍），线性动态范围的上限（即产生与颗粒（分析物）质量呈线性比例关系的信号强度的颗粒尺寸）可以大大扩展。不出所料，降低灵敏度会增加可检测到的最小颗粒尺寸。结果表明，直径达5000纳米的二氧化硅颗粒在电感耦合等离子体（ICP）中能完全汽化。
