The characterization of nanoparticles (NPs) in hydrocarbon matrices using single particle inductively coupled plasma mass spectrometry (spICP-MS) is underdeveloped. There are less than ten publications using spICP-MS in hydrocarbon matrices, and none have applied the technique to determine NP concentration and size distribution in asphaltenes after in-situ upgrading of heavy oils via solvent deasphalting. To our knowledge, no studies have used spICP-MS to track the nature of NP additives in the asphaltene fraction in hydrocarbons without adulteration of the sample. Particle number concentrations (PNC) derived from spICP-MS in hydrocarbon matrices are reported for the first time. Fe2O3 PNC increased by an order of magnitude, and NiO PNC increased 28 % compared to samples without additives, indicating that NPs were reasonably well-dispersed in the asphaltenes. Ionic concentrations were higher for Ni than Fe, which showed negligible changes in all samples. Here, we report the lowest size detection limits recorded for Fe2O3 NPs (32 nm ± 1 nm) using spICP-MS in hydrocarbon matrices. Further, NiO and Fe2O3 NP sizes matched the initial sizes added to the oil before precipitation, providing evidence that the nature of the NPs does not change after deasphaltation and subsequent mixing with asphaltenes. This study expands our understanding of the interactions between metal NPs and asphaltenes when used as co-precipitants during in situ upgrading of heavy crude oil.
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Mass Spectrometry Measurements of Neuropeptides: From Identification to Quantitation
Neuropeptides (NPs), a unique class of neuronal signaling molecules, participate in a variety of physiological processes and diseases. Quantitative measurements of NPs provide valuable information regarding how these molecules are differentially regulated in a multitude of neurological, metabolic, and mental disorders. Mass spectrometry (MS) has evolved to become a powerful technique for measuring trace levels of NPs in complex biological tissues and individual cells using both targeted and exploratory approaches. There are inherent challenges to measuring NPs, including their wide endogenous concentration range, transport and postmortem degradation, complex sample matrices, and statistical processing of MS data required for accurate NP quantitation. This review highlights techniques developed to address these challenges and presents an overview of quantitative MS-based measurement approaches for NPs, including the incorporation of separation methods for high-throughput analysis, MS imaging for spatial measurements, and methods for NP quantitation in single neurons.
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- Award ID(s):
- 1735252
- PAR ID:
- 10334576
- Date Published:
- Journal Name:
- Annual Review of Analytical Chemistry
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 1936-1327
- Page Range / eLocation ID:
- 83 to 106
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1146/annurev-anchem-061020-022048
