# Denoising Search doubles the number of metabolite and exposome annotations in human plasma using an Orbitrap Astral mass spectrometer

## TL;DR

A new denoising method improves detection of low-concentration metabolites and chemicals in human plasma, enabling better understanding of environmental exposures linked to diseases like Alzheimer's.

## Contribution

Spectral Denoising algorithm significantly enhances metabolite and exposome annotations in low-concentration human plasma samples.

## Key findings

- Denoising Search detected 2.3-fold more annotated compounds in AD patient plasma compared to traditional methods.
- Spectral Denoising improved confident compound identifications at 35-fold lower concentrations than previously possible.
- The method is robust against high levels of chemical and electronic noise.

## Abstract

Chemical exposures may impact human metabolism and contribute to the etiology of neurodegenerative disorders like Alzheimer’s Disease (AD). Identifying these small metabolites involves matching experimental spectra to reference spectra in databases. However, environmental chemicals or physiologically active metabolites are usually present at low concentrations in human specimens. The presence of noise ions can significantly degrade spectral quality, leading to false negatives and reduced identification rates. In response to this challenge, the Spectral Denoising algorithm removes both chemical and electronic noise. Spectral Denoising outperformed alternative methods in benchmarking studies on 240 tested metabolites. It improved high confident compound identifications at an average 35-fold lower concentrations than previously achievable. Spectral Denoising proved highly robust against varying levels of both chemical and electronic noise even with >150-fold higher intensity of noise ions than true fragment ions. For human plasma samples of AD patients that were analyzed on the Orbitrap Astral mass spectrometer, Denoising Search detected 2.3-fold more annotated compounds compared to the Exploris 240 Orbitrap instrument, including drug metabolites, household and industrial chemicals, and pesticides. This combination of advanced instrumentation with a superior denoising algorithm opens the door for precision medicine in exposome research.