LC-HRMS screens 9 GLP-1 agonists at once

A paper published on 21 July 2026 in the Journal of Chromatography A describes a single analytical method capable of detecting and quantifying nine structurally distinct GLP-1 receptor agonists (GLP-1 RAs) in pharmaceutical products^[1]. The method uses liquid chromatography combined with high-resolution mass spectrometry (LC-HRMS), a technique that separates compounds by their physical properties and then weighs them at the molecular level with enough precision to distinguish compounds that differ by only a few atomic masses.

The nine GLP-1 RAs covered are: bofanglutide, ecnoglutide, exenatide, liraglutide, mazdutide, retatrutide, semaglutide, survodutide, and tirzepatide. The list spans approved medicines, investigational candidates, and compounds in clinical development, reflecting the rapid expansion of this drug class over the past decade^[1].

Why analytical methods for GLP-1 agonists are technically difficult

GLP-1 receptor agonists are peptide-based therapeutics: chains of amino acids, typically ranging from around 30 to 45 residues, that mimic the action of the body's own GLP-1 hormone on the pancreas, gut, and brain. Their size, structural similarity to one another, and the chemical modifications introduced by manufacturers to extend their half-life (such as fatty acid side chains in semaglutide and liraglutide, or dual receptor targeting in tirzepatide) make them difficult to separate cleanly using simpler analytical platforms.

The challenge is compounded in a regulatory context. When a pharmaceutical product reaches a patient, the active ingredient must be present at the stated potency, free of degradation products above specified thresholds, and identifiable with certainty. The International Council for Harmonisation guideline ICH Q2(R2), adopted by the FDA and other major regulators, sets the framework for what must be demonstrated before an analytical method can be considered validated for pharmaceutical quality control: accuracy, precision, specificity, linearity, and limits of detection and quantification are all required^[2]. Multiplexed methods, which cover multiple analytes simultaneously, add another layer of complexity because the method must perform adequately for every compound in the mix.

What the Hong Kong Government Laboratory team built

The research team, based at the Analytical and Advisory Services Division of the Hong Kong Government Laboratory, developed a reversed-phase LC-HRMS method using difluoroacetic acid in the mobile phase to achieve baseline separation of most of the nine peptides within a 20-minute run time^[1]. Difluoroacetic acid is an ion-pairing reagent that interacts with the positively charged groups on peptides, helping them distribute more consistently between the mobile and stationary phases and sharpening peak shapes that would otherwise bleed into one another.

Validation results showed good linearity across a working range of 4 to 235 nanograms per milliliter, with correlation coefficients of at least 0.995 for all nine compounds^[1]. The pharmaceutical application section of the study tested the method against marketed formulations and reported recoveries of 113.7 to 118.4 percent. Recovery values above 100 percent can indicate matrix effects, where components of the sample other than the analyte itself either suppress or enhance the signal, a recognised challenge in LC-HRMS work with complex pharmaceutical matrices.

What a multiplexed method means for quality control practice

Before a method like this exists, a laboratory that receives an unknown sample containing a GLP-1 agonist would typically need to run separate, targeted assays for each compound it suspects may be present. That approach is slow and requires prior knowledge of which agonist is in the sample. A multiplexed, validated method changes the economics: a single injection can screen for nine compounds simultaneously, which is directly useful for anti-doping laboratories, customs and border enforcement agencies, pharmaceutical quality control units, and independent testing organisations.

For approved products such as semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), validated analytical methods are already part of the regulatory dossier submitted for marketing approval^[3]. What the Hong Kong study adds is a single-platform method that works across the class, including investigational compounds such as retatrutide and survodutide that have not yet reached broad commercial distribution. This kind of method is particularly relevant as the GLP-1 market has grown rapidly and supply-chain pressures have created demand for independent verification of product identity and potency.

Limitations and what the study does not address

The recovery figures above 100 percent flag a practical limitation: matrix effects can introduce systematic bias when moving from the standard solutions used for calibration to real pharmaceutical matrices. The authors note this and recommend matrix-matched calibration as a mitigation^[1]. The study also does not report full ICH Q2(R2) robustness testing, the deliberate perturbation of method parameters (column temperature, mobile-phase composition, flow rate) to assess how much variation the method can tolerate in routine use. Robustness data would be required before the method could be adopted without modification for a regulated quality-control setting^[2].

The paper also does not cover all GLP-1 agonists now in development or approved across global markets. Dulaglutide (Trulicity), albiglutide (Tanzeum, withdrawn), and oral semaglutide (Rybelsus) are not included, nor are the growing number of compounds in early-phase trials. A method covering nine agents is an advance, but the field is moving quickly enough that periodic updates will be needed.

What this means for readers interested in GLP-1 product quality

For the general public, the practical significance of this work lies in what it reveals about the complexity of verifying what is in a GLP-1 product. Prescription products manufactured under GMP conditions have validated analytical methods, regulatory oversight, and supply-chain controls built into their approval pathway. Grey-market or compounded GLP-1 peptides, circulating in a context of global shortages, carry none of those assurances. A study like this demonstrates concretely how technically demanding authentic quality verification is, requiring specialist equipment, validated methods, and reference standards that are not accessible outside a pharmaceutical-grade laboratory.

This article is provided for educational purposes. It does not constitute medical or pharmaceutical advice. Any decision about GLP-1 receptor agonist therapy belongs with a qualified clinician who can assess your individual medical history. See the semaglutide overview, tirzepatide overview, and retatrutide overview for regulatory and clinical context on specific agents covered by this method.