Sieve-based device for MALDI sample preparation. III. Its power for quantitative measurements.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Traditional MALDI deposition techniques suffer from solid sample inhomogeneity, negatively impacting quantitative analysis.
• Achieving homogeneous sample preparation is crucial for reliable and reproducible mass spectrometry results.

Purpose of the Study:

• To introduce and validate a novel sieve-based device (SBD) for homogeneous sample deposition in MALDI.
• To assess the suitability of the SBD method for quantitative protein analysis, including biological samples.

Main Methods:

• Electrospraying of matrix/analyte solutions through a grounded sieve to form homogeneous microcrystals.
• Analysis of protein mixtures with known molarities to establish linearity and intensity ratios.
• Quantification of a specific collagen precursor peptide in human urine samples.

Main Results:

• The SBD method enables homogeneous deposition of microcrystals with consistent matrix/analyte molar ratios.
• A strong correlation was observed between molarity and intensity ratios for analyzed proteins, irrespective of ionic yield differences.
• The method accurately quantified a collagen precursor peptide in urine, demonstrating its utility for biological fluid analysis.

Conclusions:

• The sieve-based device (SBD) significantly overcomes the limitations of traditional MALDI deposition for quantitative analysis.
• SBD facilitates the development of robust quantitative procedures for protein analysis in various contexts.
• This method shows particular effectiveness for quantitative analysis in biologically relevant fluids, such as urine.