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Title: Probabilistic limit of detection for ricin identification using a shotgun proteomics assay

Abstract

Robust and highly specific methods for the detection of the protein toxin ricin are of interest to the law enforcement community. In previous studies, methods based on liquid chromatography-tandem mass spectrometry shotgun proteomics have been proposed. The successful implementation of this approach relies on specific data evaluation criteria addressing (1) the quality of the mass spectrometric data, (2) the confidence of peptide identifications (peptide-spectrum matches), and (3) the number and sequence specificity of peptides detected. We present such data evaluation criteria, and use a novel approach to establish the limit of detection for this ricin assay. Specifically, we use logistic regression to determine the probability of detection for individual ricin peptides at different concentrations. We then apply basic rules from probability theory, combining these individual peptide probabilities into an overall assay limit of detection. This procedure yields an assay limit of detection for ricin at 42.5 ng on column or 21.25 ng/µL for a 2-µL injection. We also show that, in spite of the conventional wisdom that detergents are deleterious to mass spectrometric analyses, the presence of Tween-20 did not prevent detection of ricin peptides, and indeed assays performed in buffers that included Tween-20 gave better results than assays performedmore » using other buffer formulations with or without detergent removal.« less

Authors:
ORCiD logo [1];  [2]; ORCiD logo [1];  [3];  [1];  [1]; ORCiD logo [1];  [1];  [1]
  1. BATTELLE (PACIFIC NW LAB)
  2. OTHER GOVERNMENT AGENCIES
  3. National Bioforensic Analysis Center
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1569006
Report Number(s):
PNNL-SA-144376
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Analytical Chemistry
Additional Journal Information:
Journal Volume: 91; Journal Issue: 19
Country of Publication:
United States
Language:
English

Citation Formats

Heller, Natalie C., Garrett, Alaine M., Merkley, Eric D., Cendrowski, Stephen, Melville, Angela M., Arce, Jennifer S., Jenson, Sarah C., Wahl, Karen L., and Jarman, Kristin H. Probabilistic limit of detection for ricin identification using a shotgun proteomics assay. United States: N. p., 2019. Web. doi:10.1021/acs.analchem.9b02721.
Heller, Natalie C., Garrett, Alaine M., Merkley, Eric D., Cendrowski, Stephen, Melville, Angela M., Arce, Jennifer S., Jenson, Sarah C., Wahl, Karen L., & Jarman, Kristin H. Probabilistic limit of detection for ricin identification using a shotgun proteomics assay. United States. doi:10.1021/acs.analchem.9b02721.
Heller, Natalie C., Garrett, Alaine M., Merkley, Eric D., Cendrowski, Stephen, Melville, Angela M., Arce, Jennifer S., Jenson, Sarah C., Wahl, Karen L., and Jarman, Kristin H. Tue . "Probabilistic limit of detection for ricin identification using a shotgun proteomics assay". United States. doi:10.1021/acs.analchem.9b02721.
@article{osti_1569006,
title = {Probabilistic limit of detection for ricin identification using a shotgun proteomics assay},
author = {Heller, Natalie C. and Garrett, Alaine M. and Merkley, Eric D. and Cendrowski, Stephen and Melville, Angela M. and Arce, Jennifer S. and Jenson, Sarah C. and Wahl, Karen L. and Jarman, Kristin H.},
abstractNote = {Robust and highly specific methods for the detection of the protein toxin ricin are of interest to the law enforcement community. In previous studies, methods based on liquid chromatography-tandem mass spectrometry shotgun proteomics have been proposed. The successful implementation of this approach relies on specific data evaluation criteria addressing (1) the quality of the mass spectrometric data, (2) the confidence of peptide identifications (peptide-spectrum matches), and (3) the number and sequence specificity of peptides detected. We present such data evaluation criteria, and use a novel approach to establish the limit of detection for this ricin assay. Specifically, we use logistic regression to determine the probability of detection for individual ricin peptides at different concentrations. We then apply basic rules from probability theory, combining these individual peptide probabilities into an overall assay limit of detection. This procedure yields an assay limit of detection for ricin at 42.5 ng on column or 21.25 ng/µL for a 2-µL injection. We also show that, in spite of the conventional wisdom that detergents are deleterious to mass spectrometric analyses, the presence of Tween-20 did not prevent detection of ricin peptides, and indeed assays performed in buffers that included Tween-20 gave better results than assays performed using other buffer formulations with or without detergent removal.},
doi = {10.1021/acs.analchem.9b02721},
journal = {Analytical Chemistry},
number = 19,
volume = 91,
place = {United States},
year = {2019},
month = {10}
}