A rapid and reliable liquid chromatography/mass spectrometry method for SARS-CoV-2 analysis from gargle solutions and saliva

Abstract

We describe a rapid liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the direct detection and quantitation of SARS-CoV-2 nucleoprotein in gargle solutions and saliva. The method is based on a multiple-reaction monitoring (MRM) mass spectrometry approach with a total cycle time of 5 min per analysis and allows the detection and accurate quantitation of SARS-CoV-2 nucleoprotein as low as 500 amol/μL. We improved the sample preparation protocol of our recent piloting SARS-CoV-2 LC-MS study regarding sensitivity, reproducibility, and compatibility with a complementary reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) analysis of the same sample. The aim of this work is to promote diagnostic tools that allow identifying and monitoring SARS-CoV-2 infections by LC-MS/MS methods in a routine clinical environment. Graphical abstract

Isothermal gene amplification coupled MALDI-TOF MS for SARS-CoV-2 detection

“…The ICP-MS based method employed additional nanoparticle probes to detect the specific nucleic acids of SARS-CoV-2 [ 33 , 34 ]. LC-MS and high resolution MALDI-MS were used to detect virus proteins directly [ 35 , 36 ]. MALDI-MS were also combined with PCR to detect virus nucleic acids [ 27 ].…”

Ultrasensitive Detection of SARS-CoV-2 Spike Proteins Using the Thio-NAD Cycling Reaction: A Preliminary Study before Clinical Trials

“…We should comment on the other methods to detect proteins in SARS-CoV-2. The nucleocapsid proteins in SARS-CoV-2 detected by liquid chromatography/tandem mass spectrometry (LC-MS/MS) were usually at the levels of 10 −16 moles/µL, and thus Kipping et al has recently improved the detection sensitivity to the levels of 10 −18 moles/µL in their LC-MS/MS study [36]. If it is allowed to change "per µL" to "per 100 µL" (i.e., our one assay volume), the detectable molecule number is 10 −16 moles/100 µL.…”

Cov2MS: an automated matrix-independent assay for mass spectrometric detection and measurement of SARS-CoV-2 nucleocapsid protein in infectious patients

“…The new assay also performs very robustly when using saliva and plasma. Thus, a variety of sample matrices could potentially be used in the future if the viral load is adequately high in such biological fluids 24,25 . Equally important, the detection of viral peptides in plasma creates the possibility for direct detection of viral load in blood, in turn enabling the assessment of disease status, clinical prognostic value and treatment monitoring.…”