High Sensitivity Mass Spectrometric Quantification of Serum Growth Hormone by Amphiphilic Peptide Conjugation

TL;DR

This study introduces a highly sensitive mass spectrometry method for quantifying serum growth hormone using amphiphilic peptide conjugation, significantly improving detection limits for clinical diagnostics.

Contribution

The paper presents a novel derivatization technique with IPDOA-iodide that enhances mass spectrometric detection of growth hormone in serum, enabling accurate measurement at very low concentrations.

Findings

Signal enhancement allows detection at 0.4 μg/L.

Coefficient of variation (CV) was 3.5%.

Method successfully applied to patient samples.

Abstract

Amphiphilic peptide conjugation affords a significant increase in sensitivity with protein quantification by electrospray-ionization mass spectrometry. This has been demonstrated here for human growth hormone in serum using N-(3-iodopropyl)-N,N,N-dimethyloctylammonium iodide (IPDOA-iodide) as derivatizing reagent. The signal enhancement achieved in comparison to the method without derivatization enables extension of the applicable concentration range down to the very low concentrations as encountered with clinical glucose suppression tests for patients with acromegaly. The method has been validated using a set of serum samples spiked with known amounts of recombinant 22 kDa growth hormone in the range of 0.48 to 7.65 \mug/L. The coefficient of variation (CV) calculated, based on the deviation of results from the expected concentrations, was 3.5% and the limit of quantification (LoQ) was determined as 0.4 \mug/L. The potential of the method as a tool in clinical practice has been demonstrated with patient samples of about 1 \mug/L.