MS Grade

MS Grade: Overview

MS-grade (mass spectrometry grade) reagents are high-purity chemicals and biologicals that are:

· Low in contaminants (especially salts, detergents, metal ions, and polymers)

· Free of interfering ions, which helps reduce background noise

· Highly reproducible, ensuring minimal variability in MS signal

These reagents are critically important for:

· Enhancing signal-to-noise ratio

· Improving sensitivity and quantitation

· Protecting instrument performance (less contamination of ion source or LC columns)

Categories of MS-Grade Biological Reagents

1. MS-Grade Solvents

Used in sample prep, mobile phases, and peptide cleanup.

Solvent	Applications	MS-Grade Brands/Types
Acetonitrile	LC-MS mobile phase	Thermo Fisher Optima, Sigma LC-MS
Methanol	Sample extraction, mobile phase	LC-MS grade
Isopropanol	Protein precipitation	LC-MS grade
Water	Reconstitution, dilution	LC-MS or HPLC grade, 0.2 µm filtered
Formic Acid	Ionization enhancement	Optima (Fisher), MS-grade TFA
TFA / Acetic Acid	Peptide elution, suppression tuning	Sequencing grade

2. MS-Grade Enzymes

Used in proteomics for protein digestion.

Enzyme	Purpose	MS-Grade Examples
Trypsin	Cleaves at K/R sites	Promega Trypsin Gold, Thermo MS-Grade Trypsin
Lys-C, Glu-C	Enhanced cleavage	Sigma sequencing-grade Lys-C
PNGase F	N-glycan removal	NEB MS-compatible PNGase F

Features:

· Highly purified and modified to resist autolysis

· Free from keratin or microbial contamination

3. MS-Compatible Detergents & Surfactants

Aid in protein solubilization while being MS-friendly.

Surfactant	Property	Examples
RapiGest	Acid-cleavable	Waters
ProteaseMAX	Solubilizing + degradable	Promega
SDC (sodium deoxycholate)	Precipitable after acid	Sigma MS-grade SDC

Avoid using SDS or Triton X-100 unless removed prior to MS.

4. Reducing and Alkylating Agents

Used in sample denaturation and disulfide bond cleavage.

Reagent	Use	MS-Grade Notes
DTT	Reducing agent	Free from thiol contaminants
TCEP	Stable reducing agent	Non-volatile, odorless
IAA / CAA	Alkylating agents	Prevent disulfide reformation

5. Peptide/Protein Standards and Calibration

For normalization, quantification, or retention time alignment.

Standard	Use	Examples
iRT Peptides	Retention time calibration	Biognosys
Heavy-labeled peptides	Absolute quantitation	Thermo, JPT
Digested protein standards	Instrument calibration	BSA, Myoglobin digest (MS-certified)

6. Desalting & Cleanup Reagents

Crucial for removing MS-inhibiting contaminants before injection.

Tool/Reagent	Use	Brands
C18 ZipTips	Peptide desalting	Millipore, Thermo
StageTips, SPE	Sample concentration	Waters Sep-Pak, Oasis
Magnetic beads (SP3)	Proteomics sample prep	Thermo, GE Healthcare

Best Practices When Using MS-Grade Reagents

· Check for MS-grade certification: Don't assume purity based on regular analytical grade labels.

· Use gloves and filtered pipette tips: Avoid keratin and other contaminants.

· Avoid plasticizers and leachables: Choose low-binding plastic or glass containers.

· Pre-wash containers: Especially when using for long storage or mobile phase mixing.

· Test new lots with a standard peptide mix to ensure low background.

View all MS Grade products