LC-MS Analysis, Hybrid LC-MS Assay and Mass Spec Service by PhDs at 20+ Year, FDA-Inspected Lab

Liquid Chromatography Mass Spectrometry (LC-MS) is a method or technique used commonly for drug analysis, food analysis, and environmental testing. The advantage of LC-MS analysis is that it enables both high throughput and high sensitivity analysis of analytes. LC-MS assay is increasingly used for a variety of compounds leading to accelerated testing and development of drug candidates. Similarly, LC-MS analysis is one of the most commonly used techniques for conducting DMPK studies. Liquid Chromatography Mass Spectrometry combines the physical separation and detection sensitivity capabilities of both platforms.

In other words, the individual abilities of both the LC and MS techniques are synergistically enhanced by their tandem combination. LC-MS analysis works so well because the Liquid Chromatography separates analyte from a complex matrix into distinct components, while the Mass Spectrometry provides the characterization and quantitation for the components with high accuracy. This technique works exceptionally well for the analysis of both synthesized inorganic compounds, as well as organic and biochemical compounds found in complex biological and environmental matrices. For 20+ years, pioneering biotech/pharma companies rely on our LC-MS/MS Analysis experts to drive industry-leading value and turnaround. Our FDA audited LC-MS testing lab always generates reliable and robust data for your pivotal studies. We routinely pilot a wide variety of GLP LC-MS Method Development and Validation projects to meet your critical bioanalysis milestones.

The LC-MS assay method is used during various stages of the drug development cycle. Most notably, it is used in the following phases:

Drug Discovery:

Over the past couple of decades, high-performance liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) analysis has emerged as one the preferred analytical technique for new drug discovery assays.

Preclinical Toxicology:

Studies range from early lead optimization to dose range finding studies followed by Tox studies. These studies involve primarily plasma and tissue samples of rodent and non-rodent species. Typically, GLP toxicology studies are performed using fully validated LC-MS methods. Theoretically, this could be accomplished using HPLC with UV and other detection methods like fluorescence, but these detection methods aren’t as selective and require extensive sample preparation. Use of MS detection in multiple reaction monitoring mode (MRM) is quite selective, and therefore drugs can be analyzed in biological matrices with simple cleanup steps. Also, LC-MS assay can be developed relatively faster for a new drug and are generally very robust and reliable.

Clinical trials:

These studies range from Phase 1 (dose escalation studies like single ascending and multiple ascending dose, healthy volunteer studies) to Phase III, Phase IV and post-marketing studies. Matrices involved in the analysis range from plasma, serum, blood, urine, feces, and tissues from different organs. Over the last 10-15 years, the LC-MS/MS method has rapidly become the method of choice during clinical trials. At the early stages of clinical development, it is essential to analyze plasma samples from clinical trials for understanding ADME properties of the drug and ensuring data consistency with preclinical PK studies. Thus, LC-MS/MS methods are developed and validated for the drug analysis and testing in human biological fluids.

With 20+ years of LC-MS method development behind us, the sequence is settled: establish how the molecule ionizes, select parent and product transitions, then optimize source parameters, chromatography and extraction against your matrix. It takes a few deliberate iterations to lock a method that quantifies cleanly at the LLOQ your study needs, and the development report documents the reasoning, not just the settings, so validation starts on solid ground.

The terms are often used interchangeably, but technically LC-MS refers to a single quadrupole system and LC-MS/MS to a triple quadrupole, where Q1 and Q3 filter masses and Q2 fragments the analyte. In a clean solution a single quad can look comparable; in plasma or tissue the second stage of filtering is what removes interference, so LC-MS/MS delivers the cleaner, more reliable quantitation. Every regulated PK and TK assay here runs on triple quadrupole or better.

A pre-validation test run proves the method is fit to enter validation before validation dollars are spent: stock solutions, a practice calibration curve and quality controls are run to confirm range, stability indicators and reproducibility. FDA and other agencies require full validation for each test article, matrix and instrument system before regulated sample analysis; the test run is how we make sure that validation passes the first time.

If your analyte sits at a reasonable concentration in a clean matrix, HPLC with UV or fluorescence detection is often enough, and we will say so rather than quote mass spectrometry you do not need. Low concentrations, complex matrices like plasma or tissue, or co-eluting interferences are where LC-MS/MS earns its cost. Both platforms run under this roof, so the method starts where your molecule actually needs it and escalates only if the data says to.

Yes, and transfer is usually faster and cheaper than building again. Send the method, the validation report and recent chromatograms under CDA. We read the gap within days, tell you what transfers clean and what needs partial validation, then replicate the method on like-for-like instruments before any study sample is touched. Bridging data ties your old results to the new ones so the dataset reads as one.

A written scope and timeline come back within two business days of your inquiry. Method development typically runs two to four weeks depending on the molecule and matrix, and a full GLP validation on LC-MS/MS typically takes two to three weeks. Study samples then run batch by batch, with cohort turnarounds agreed against your study calendar before we start.

LC-MS assay offers a sensitive, selective, and reliable approach for analyzing diverse molecules. Different mass spectrometer models provide advantages and disadvantages for viable LC-MS analysis over mass ranges and detection limits. Most biomolecules utilized as reference materials for drugs, metabolites, or endogenous biomarkers, including drugs, peptides, nucleic acids, and other endogenous or synthesized molecules, can be assayed using triple quadrupole mass spectrometry. Triple quads, however, have limited mass ranges, and intact proteins and large biomolecules can alternatively be assayed by other LC-MS testing techniques, including time-of-flight (TOF) or other high-resolution mass spectrometers (HR-MS). Inductively coupled plasma mass spectroscopy (ICP-MS) is especially useful for metallic ion assay in environmental chemistry and clinical toxicology.

In LC-MS lab setting, aqueous and organic solvents, dosing vehicles, or other drug formulations prepared for in vivo or in vitro testing, and biological fluids and tissues are routinely quantified for drug substances, metabolites, and biomarkers. Biological samples for LC-MS analysis may include Blood, Plasma, Serum, Tissue Homogenates/Extracts (Liver, Lung, Kidney, Brain, Tumor, Arterial, Tendon, Skin, etc.), Translucent Matrices (Urine, Cerebrospinal, Tears, Synovial, Aqueous, etc.), Cell Lysates, and several other body fluids or membranes.

For solid tissue samples, sample homogenization is typically performed as part of the sample processing for LC-MS testing. For all matrices, samples must be extracted into solvents suitable for injection for LC-MS assay. Protein precipitation (PPT), liquid-liquid extraction (LLE), and solid-phase extraction (SPE) are the most commonly used sample extraction techniques used in LC-MS labs during sample preparation for LC-MS analysis. The extraction method employed is verified during LC-MS/MS method development and method validation.

In any LC-MS testing method, the required sample volume depends on multiple factors such as calibration range, compound sensitivity, chromatography column, matrix-based suppression or enhancement, mobile phase selection, and detector linearity. Often, LC-MS method sample volume requirement can vary between 2 µL-200 µL. We can use specialized systems such as capillary flow for shallow volumes. Our scientists recommend collecting additional sample volume in pharmacokinetic/toxicokinetic assessments from biological samples to complete reassay or incurred sample reanalysis (ISR) to support your LC-MS method validation.

All high-Quality LC-MS method validations ensure that the analyte of interest can be detected selectively, accurately, and precisely in an appropriate calibration range suitable for sample analysis. Furthermore, these LC-MS method validations must include proper safeguards to verify all test compounds are stable during sample collection, storage, and processing. To that end, FDA guidelines on chromatographic method validation mandate demonstrating selectivity, specificity, sensitivity, accuracy, precision, recovery, and stability under storage and test conditions. Usually, a change in analyte, detection range, or sample matrix results in a shift in the method and the need for additional LC-MS method validation. Frequently, LC-MS assays are validated on any system and for any analyst performing the LC-MS method to ensure that LC-MS/MS analysis results are robust, reliable, and reproducible.

LC-MS/MS platform offers higher throughput than gas chromatography-mass spectrometry (GC-MS) and analytical specificity superior or comparable to immunoassays. However, LC-MS/MS has numerous limitations, most of which revolve around the interacting triangle of sensitivity, specificity, and throughput. While sample throughput is better than traditional HPLC or GC-MS, it still falls short of automated immunoassays. Direct sample injection, LC-multiplexing, and sample multiplexing are all evolving methods for increasing LC-MS throughput. Sample cleaning and chromatography optimization are two ways to further improve specificity and sensitivity by avoiding interferences and ion suppression caused by sample matrix components. Additional advantages may be available to the LC-MS platform with next-generation instruments. Among other matters, peptide/protein analysis is the next barrier for clinical LC-MS/MS. Targeted peptide and protein testing by LC-MS/MS, directed at analytical and clinical questions that need answering, is proving extremely effective.

Generally, triple-quadrupole mass spectrometers are used in analytical and bioanalytical LC-MS laboratories for quantitative small-molecule applications due to their selectivity and sensitivity advantages. Time-of-Flight (TOF) and QTrap LC-MS models are more commonly used in qualitative applications, such as metabolite or structural identification, combined with alternate analytical approaches such as nuclear magnetic resonance (NMR). Laser desorption mass spectrometers (MALDI and SELDI) can be used to analyze large molecular weight biomolecules. Inductively coupled plasma mass spectroscopy (ICP-MS) is utilized to study metallic ions, often in environmental labs and toxicology settings to diagnose heavy metal or radioisotope exposure.

Buffers and mobile phase solvents used in LC-MS applications should ideally only contain volatile components. The most common volatile salts for buffering in LC-MS mobile phases are ammonium formate and ammonium acetate. Here, adjustments in pH are performed with volatile acids and bases such as formic acid and ammonia. Usually, some non-volatile components get introduced during assays of biological samples with sample injections. Mass spectrometer instruments can handle small amounts of these non-volatile components with routine cleaning and maintenance.

In LC-MS assays, a mechanical region in the flow path is often the source of carryover. Most commonly, carryover occurs in the autosampler needle or chromatographic column used for the assay. Lab technicians can inject blanks during LC-MS analysis to gradually dilute the hold-up of partial samples, resulting in less carryover with each pass. Similarly, we can apply an organic solvent as a needle wash solution when analyzing hydrophobic samples to minimize carryover by solubilizing and washing away the adsorbed sample components. Advanced instrument models allow for more solvents, higher flow rates, and other advanced washing mechanisms to help reduce autosampler-based carryover. We can minimize chromatographic carryover by sample dilution, smaller injection volumes, or changes in the stationary and mobile phases of the assay.

We can compare replicate LC-MS/MS runs using experimental duplicate to inform us on precision further and help assess whether our LC-MS method and sample analysis are performing as expected. Generally, replicate samples are analyzed on an as-needed basis for LC-MS testing due to resource constraints and relatively longer run times associated with chromatographic assays.

For many molecules, methods for UV/Vis detection may be modified for detection by mass spectroscopy. Often, LC-MS analysis will offer an improved selectivity, sensitivity, and linear dynamic range relative to LC-UV/Vis analysis. Modifications to the method typically include switching to volatile mobile phases for compatibility with MS source introduction and selecting a more appropriate internal standard, such as a stable-labeled isotope of the analyte, for LC-MS method development and validation as well as during sample quantitation.