While investment decisions often focus on mass spectrometry (MS) detection, experience across clinical laboratories shows that chromatography is frequently the limiting factor, both scientifically and financially.

When chromatographic performance is unstable, the cost is not confined to poorer data quality. It appears as lost productivity, reanalysis, delayed reporting, and increased operational risk. In this environment, Ultra High Performance Liquid Chromatography (UHPLC) technology is essential for protecting return on investment (ROI) in clinical LC‑MS workflows.

The hidden financial cost of unstable chromatography

In routine clinical laboratories, chromatography must perform reliably across:

• Hundreds to thousands of samples per day
• Complex and variable biological matrices
• Multiple operators and long assay lifetimes
• Regulated and audited workflows

When it does not, the consequences are immediate and costly. Retention time instability and poor chromatographic reproducibility lead to:

• Wider MS acquisition windows
• Reduced dwell time and fewer data points per peak
• Increased risk of missed detections in large analyte panels
• Higher rates of manual data review, reruns, and batch failures

Each of these outcomes consumes analyst time, instrument capacity, reagents, and consumables; eroding throughput and increasing cost per result. Over time, these inefficiencies quietly undermine the financial viability of LC‑MS testing.

Retention time stability drives both performance and productivity

Retention time stability is often discussed as a technical metric, but in clinical LC‑MS it has direct economic implications. Stable retention times allow laboratories to:

• Use narrow, confident MS acquisition windows
• Increase dwell time per transition
• Generate more robust quantitative data per injection
• Reduce uncertainty that forces manual review

When retention times drift, acquisition windows are often widened “just in case.” This precaution reduces MS efficiency and sensitivity, especially for low‑abundance analytes, increasing the likelihood of reanalysis or inconclusive results.

In high‑throughput environments, retention time variability is one of the fastest ways to increase your cost per sample while reducing throughput.

UHPLC as a cost‑containment and risk‑reduction strategy

For clinical laboratories, UHPLC is not simply about achieving better separation—it is about controlling operational and financial risk. Robust, stable UHPLC reduces:

• Missed detections that require repeat analysis
• Batch failures triggered by chromatographic drift
• Analyst time spent on troubleshooting and manual review
• Variability that complicates trending and audit investigations

By stabilizing chromatography, laboratories stabilize workflow efficiency, instrument utilization, and reporting timelines—directly contributing to improved ROI over the assay lifecycle.

ACQUITY UPLC I‑Class PLUS System: Designed for long‑term ROI in clinical labs

The Waters ACQUITY UPLC I‑Class PLUS System was developed with decades of expertise. Rather than prioritizing maximum pressure or speed alone, the system is engineered to deliver:

• Highly stable solvent delivery for consistent retention times
• Precision injection supporting reproducible LC‑MS acquisition
• Robust operation suitable for continuous, high‑throughput use
• Design principles aligned with regulated clinical environments

The result is not simply higher performance, but fewer workflow interruptions, lower rework rates, and more predictable assay behaviour over time.

The takeaway

As clinical LC‑MS testing expands, laboratories must evaluate technology choices not only on analytical capability, but on total operational impact.

Unstable chromatography increases cost per sample, consumes valuable staff time, and introduces unnecessary risk. Stable, clinically optimized UPLC enables higher throughput, consistent performance, and predictable outcomes across the life of the assay.

With systems such as the ACQUITY UPLC I‑Class PLUS System, UHPLC helps ensure that chromatography strengthens the return on investment in modern clinical LC‑MS.

Explore how UPLC can reduce risk and increase efficiency in your clinical lab.

Chromatography is often the root cause of the variability observed at the mass spectrometer.

Today’s MS platforms are technologically mature, electrically stable, and highly reproducible over time. When signal changes occur, the detector is usually doing exactly what it was designed to do:  reporting the conditions under which analytes entered the ion source.

Those conditions are set upstream by chromatography.

Chromatography determines what is delivered to the MS

Before an analyte ever reaches the mass spectrometer, chromatography determines when it arrives, how concentrated it is at any given moment, and which other components arrive alongside it. Retention time, peak width, peak shape, and co‑elution patterns all originate in the LC system.

Any variability in these parameters is immediately translated into variability at the MS. From the detector’s perspective, changing chromatography appears as changing signal response, even if the MS itself is perfectly stable. This is why apparent “MS variability” so often persists despite tuning, cleaning, or servicing the mass spectrometer.

How chromatographic instability manifests as MS variability

One of the most common contributors is retention time instability. When retention times shift, acquisition windows must be widened to avoid missed detections. Wider windows reduce dwell time per transition, decrease the number of data points across the peak, and increase exposure to interfering signals. The result is poorer precision and less consistent quantitation.

Peak broadening, often caused by extra‑column dispersion, has a similar impact. When an analyte band is spread out after leaving the column, the same amount of analyte is delivered to the ion source over a longer period. Peak height drops, signal‑to‑noise suffers, and integration becomes less consistent. Again, the MS registers variability that originated from the chromatography.

Matrix co‑elution further compounds the problem. Inadequate chromatographic separation allows more background components into the ion source, increasing ion suppression or enhancement. These matrix‑driven effects are highly variable and can make MS response appear unstable, even though the underlying cause is insufficient chromatographic control.

Why does this matter more in clinical laboratories

Clinical LC‑MS workflows amplify the impact of chromatographic variability. High‑throughput operation, large multi‑analyte panels, complex biological matrices, and long assay lifetimes leave little tolerance for drift or inconsistency.

Small chromatographic changes that might be manageable in research settings become serious operational issues in clinical labs. Over time, they lead to increased manual data review, more frequent reruns or failed batches, difficulty trending system suitability metrics, and reduced confidence during audits and inspections.

Crucially, the mass spectrometer cannot correct for unstable chromatography. It can only report the consequences.

Stabilizing chromatography stabilizes the MS

When chromatography is stable, MS analytical variability decreases.

Stable retention times allow narrow, confident acquisition windows. Consistent peak shapes ensure reproducible ionization conditions. Reduced dispersion preserves peak height and signal quality. Together, these factors lead to more reproducible MS signals, improved quantitative precision, and more reliable detection of low‑level analytes.

In many cases, improving chromatographic stability is the most effective and sustainable way to improve overall LC‑MS performance.

The Role of UHPLC and Low‑Dispersion System Design

Modern UHPLC systems designed for clinical use address key chromatographic drivers of MS variability by delivering high efficiency alongside long‑term reproducibility.

Low‑dispersion system designs are particularly important, as they preserve the narrow peaks generated by UHPLC columns and maintain predictable retention time behavior.

By minimizing variability in analyte delivery to the ion source, these systems reduce apparent MS variability at its source.

The Waters ACQUITY UPLC I‑Class PLUS IVD System reflect this philosophy. The system design prioritizes stable solvent delivery, precision injection, ultra‑low dispersion, and consistent chromatographic behaviour over extended routine operation—attributes that directly translate into more reproducible MS data in clinical workflows.

The takeaway

When LC‑MS variability appears, it is tempting to look downstream. But in clinical workflows, the mass spectrometer is often responding correctly to unstable conditions created upstream.

Chromatography determines when, how, and under what conditions analytes reach the MS. If chromatography varies, then MS data will vary with it.

For clinical laboratories seeking reliable, scalable, and defensible LC‑MS, the most effective place to reduce variability is not the detector, but the chromatography that feeds it.

Learn more about the impact of UPLC on clinical analysis.

In pharmaceutical quality control (QC), consistency should mean more than an analyst ending a shift relieved that the results were repeatable and there were no obvious failures. It should mean having enough confidence in the process, the controls, and the data to know that those results are genuinely reliable, explainable, and sustainable over time. This is where Stage 3 process verification becomes so important.^1,2

Stage 3 is the ongoing phase of the analytical procedure lifecycle, where the laboratory verifies during routine use that the procedure remains in a state of control.^1,2 It shifts the focus away from a purely reactive model, where laboratories respond only after an out-of-specification (OOS), out-of-trend (OOT), or investigation appears, and toward a more mature way of working—one built on vigilant monitoring, traceability, and evidence-based oversight.^2,4

Why can validation alone no longer build confidence?

That shift matters because the regulatory expectation has changed. A validation package on its own is no longer enough to create confidence that a laboratory process remains fit for purpose. What matters now is whether the laboratory can show that its procedures continue to perform reliably in routine use, that sources of variability are being watched, and that decisions are supported by data rather than assumption.^1,2

As regulatory expert Peter Baker (Live Oak Quality Assurance LLC) noted in a recent webinar on Managing Method Variability: A Foundation for Risk-Based Change, “We really have to change the way we define validation.”⁴ That is a strong message for QC teams, because it shifts the conversation from validation as a completed exercise to control as an ongoing expectation. The question is no longer only whether a method was validated once. It’s now whether the laboratory can show that the method remains under control throughout its entire lifetime of use.^1,2

Vigilant monitoring: Detecting drift before it escalates

Ongoing verification matters because it gives QC teams a structured way to see developing signals earlier, understand whether procedure performance is starting to drift, and respond before variability becomes disruptive.^2,4 In a different webinar, Managing Process Performance in Stage 3 Process Validation: Regulatory Expectations for Continued Process Verification, Peter stressed the importance of laboratories understanding where variability exists within methods and procedures, and the need for monitoring programs to be implemented before those issues turn into investigations.⁴ This is the real value of Stage 3 verification. Continuous control starts with knowing what to watch, and then watching it consistently.^2,3

This broader view of monitoring is also why simply trending final results is not enough. Final results matter, of course, but on their own they do not always tell the laboratory where the problem is coming from. Peter made that point directly in the webinar when he explained that, if you are only trending the end result, “you don’t know whether the high or low result is due to the product or the method.”⁴

For QC laboratories, this is a critical distinction. When an investigation starts, time is already against you. If monitoring has been limited to final results only, the lab may not have enough visibility to determine whether the underlying signal points to the procedure, the sample, the instrument, or the process. Vigilant monitoring is what reduces that ambiguity.^2,4

Traceability: Turning data into defensible evidence

This is where traceability becomes a practical requirement, not just a compliance concept. If the laboratory can see what happened, who did what, what changed, and how results were reviewed, then data becomes easier to trust and easier to defend.^2,4 Such traceability is especially important in pharma QC, where data is used to support batch decisions, trend stability, justify investigations, and demonstrate control during inspection. A laboratory that can show its reviewers, auditors, and regulators a clear line from execution to review to conclusion is in a much stronger position than one that has to reconstruct the story after the fact. Consistent operations and compliant decision making both depend on that visibility.^2,4

This also changes how confidence is built in QC. Confidence should not come from the absence of obvious failures alone. It should come from evidence that the process is behaving as expected and that any emerging signs of drift will be seen and understood early enough to act. Peter made that point clearly in the webinar when he said that “accuracy and completeness are the two factors that FDA is really looking for.”⁴

For QC laboratories, that is the heart of the issue. Audit trails, review practices, process knowledge, trend analysis, and procedural controls matter because they support those two outcomes.^2,4 Once Stage 3 verification is viewed through that lens, its purpose becomes much clearer. It is not about creating more review for the sake of it. It is about maintaining confidence that the system remains in control and that the data can support critical product quality decisions.^2,3

From audit readiness to operational advantage

This is where Stage 3 verification moves beyond simple compliance and becomes a real operational advantage. A laboratory that monitors the right indicators is better able to detect drift early, identify repeat issues before they escalate, and distinguish isolated noise from a genuine performance signal.^2,3 That makes investigations more focused, root cause work more effective, and day-to-day operations more resilient. It also reduces the amount of firefighting that so often pulls QC teams away from productive work. Continuous control is not about adding more oversight for the sake of it; it’s about making sure the laboratory can stay in a state of control with fewer surprises and fewer decisions based on incomplete information. Continuous control means continuous confidence.^2,4

For pharma QC, that kind of confidence matters at every level: analysts need confidence that procedures are behaving as expected, supervisors need confidence that trending and review processes will highlight emerging issues in time, and quality leaders need confidence that the laboratory can explain its performance clearly and defend its decisions during inspection. That’s what a mature quality system looks like in practice. It is controlled, confident, and compliant, not because it says so, but because the evidence is there in the data, the review process, and the operational discipline that supports them.^2,4 The next step is making that evidence easier to generate, review, and defend consistently—day after day, method after method.

This is where Waters can help, enabling laboratories to generate, review, and defend that evidence through integrated systems, reproducible chromatographic technologies, traceable workflows, data intelligence tools, and expert services. The Waters approach combines purposefully designed instrumentation, scalable chemistries, informatics, and professional support to strengthen control from method design through routine monitoring.⁵

Empower Software supports audit‑ready operations by creating traceable records through audit trails and compliance‑enabled workflows, and Empower Subscriptions can make it easier to stay current with updates and related cloud‑based applications, reducing upgrade burden while maintaining compatibility and security as requirements evolve. In parallel, Waters Data Intelligence Software is designed to trend key measures, visualize risk, and support audit-readiness through data‑driven oversight.⁷

Waters Professional Services, Software Compliance Services, Instrument Qualification Services, and Empower Software‑based system services can then help laboratories deploy, qualify, validate, and maintain these approaches to support consistent operations and inspection readiness across the lifecycle.⁵

The message from regulators is clear. In modern pharma QC, confidence doesn’t come from a validation report alone. It comes from continuous evidence that the operation remains in control.^1,2 Stage 3 process verification is what helps laboratories create that evidence. It allows them to monitor what matters, reduce ambiguity, strengthen traceability, and build decisions on data rather than assumption.^2-4

That’s the foundation of consistent operations. It’s also the basis for a laboratory that is ready, every day, to show that its processes are controlled, its data is trustworthy, and its decisions can stand up to scrutiny. Built on control and backed by data.^2,4

Special thanks to Peter Baker, President, Live Oak Quality Assurance LLC, for generously sharing the regulatory insights and practical perspectives from the webinar series that informed this article.

To hear Peter Baker’s perspectives on Regulatory Expectations for Continued Process Verification in full, watch the webinar.

References

1. International Council for Harmonisation. (2023). ICH harmonised guideline Q14: Analytical procedure development. Adopted 1 November 2023.

2. United States Pharmacopeia. (2021). <1220> Analytical Procedure Life Cycle. USP–NF. Rockville, MD: United States Pharmacopeial Convention.

3. International Council for Harmonisation. (2023). ICH harmonised guideline Q9(R1): Quality risk management. Adopted 18 January 2023.

4. Baker, P. (2026). Webinar Managing Process Performance in Stage 3 Process Validation: Regulatory Expectations for Continued Process Verification.

5. Audit Ready Labs with Risk-Based Quality Control.

As clinical laboratories increasingly rely on LC‑MS for high‑throughput, multi‑analyte testing, retention time stability has become a defining factor in assay robustness, data quality, and operational confidence.

Why does retention time stability matter in clinical workflows

In research settings, small shifts in retention time may be tolerable. In clinical laboratories, they are not. Clinical LC‑MS assays are expected to deliver:

• Consistent results across long assay lifetimes
• High throughput with minimal manual intervention
• Defensible data in regulated and audited environments

When retention times drift, laboratories are forced to widen MS acquisition windows to avoid missing analytes. This creates a cascade of downstream effects, including:

• Reduced dwell time per transition
• Fewer data points across each chromatographic peak
• Increased susceptibility to interference
• Compromised quantitative precision, particularly for low‑level analytes

In large panels, even modest variability can lead to missed detections, increased manual review, and higher rates of reruns or batch failures. In practice, retention time stability is a prerequisite for scalable, high‑confidence clinical LC‑MS.

The link between retention time stability and MS performance

MModern tandem mass spectrometers are capable of extremely fast acquisition, but their performance is fundamentally constrained by chromatographic predictability.

Stable retention times enable laboratories to:

• Use narrow, well‑defined acquisition windows
• Optimize dwell time for each transition
• Increase the number of data points across peaks
• Maintain consistent peak integration and quantitation

When chromatography is unstable, mass spectrometry efficiency is lost, not because of the detector, but because the acquisition strategy must compensate for uncertainty upstream.

In this way, chromatography does not merely precede detection. It defines how effectively MS technology can be used in routine clinical workflows.

Why is UHPLC critical for retention time stability

Ultra-High Performance Liquid Chromatography (UHPLC) is often associated with sharper peaks and faster separations. In clinical LC‑MS, however, its most important contribution is reproducible chromatographic behavior over time. UHPLC systems designed for clinical use offer:

• Improved control of mass transfer and dispersion
• Greater consistency across injections and batches
• Reduced sensitivity to small changes in system conditions

These attributes translate directly into more stable retention times, which is particularly important when operating large panels in complex biological matrices. However, achieving retention time stability in a clinical environment requires more than high pressure alone. It requires systems engineered explicitly for robust, routine operation.

Retention time stability as a risk‑reduction strategy

From a clinical perspective, retention time stability is not just an analytical parameter, it is a risk‑reduction mechanism. Stable chromatography supports:

• Lower rates of assay failure and reanalysis
• Reduced manual data review
• Cleaner trending of system suitability metrics
• Greater confidence during audits and inspections

Conversely, unstable retention times can drive deviation investigations, complicate method maintenance, and erode trust in results over time.

For laboratories managing regulated workflows, chromatographic stability directly supports quality and compliance objectives.

Waters ACQUITY UPLC I‑Class PLUS IVD System: Designed for retention time confidence

The ACQUITY UPLC I‑Class PLUS IVD System has been engineered to deliver the level of retention time stability required for routine clinical diagnostics. This design philosophy reflects the realities of clinical laboratories, where consistency across shifts, operators, and time is paramount.

By providing highly reproducible retention times, the ACQUITY UPLC I‑Class PLUS IVD System enables:

• Narrow acquisition windows
• Efficient use of MS dwell time
• Reliable quantitation across high‑volume sample sets
• Sustained performance throughout the assay lifecycle

Chromatography expertise matters in clinical implementation

Retention time stability is not achieved by hardware alone. It reflects decades of chromatographic understanding applied to system design and clinical use cases.

Waters leadership in UHPLC technology, and its long experience supporting regulated laboratories has shaped how systems, like the ACQUITY UPLC I‑Class PLUS IVD System, are optimized for real‑world clinical operation.

In today’s clinical laboratory, retention time stability is not just a technical detail. It is the foundation of trust in LC‑MS results.

Discover how UPLC can elevate your clinical analysis.

That’s the real shift in the regulatory conversation. The old mindset treated validation as a staged event. You completed the studies, wrote the report, and called the method validated. That isn’t how it’s viewed anymore.

As regulatory expert Peter Baker (Live Oak Quality Assurance LLC) noted in a recent webinar series, “We really have to change the way we define validation.”¹

The expectation now is much closer to lifecycle thinking.^2,3 A method isn’t considered strong simply because it passed a validation protocol years ago. It has to continue delivering accurate, complete, and defensible data over time. That starts upstream, in development.

What are regulators really concerned about?

If you strip the language back, the concern is actually very simple. Can you trust the data? More specifically, is the data accurate, and is it complete? Those are the two questions that matter most.

Peter Baker captured that point directly when he said that “accuracy and completeness are the two factors that FDA is really looking for.”¹ Everything else, including controls, procedures, documentation, audit trails, assessments, validation studies, is there to support those two questions. If method design doesn’t support accuracy and completeness, then the rest of the package is weaker than people think.

That’s why method design matters so much. Accuracy isn’t protected just by choosing a detector or writing a sample preparation SOP. It depends on the full analytical workflow, including sample preparation, instrument conditions, data handling, analyst interaction, procedural controls, and the way variability enters the process. If those things aren’t thought through during development, then parts of method performance are being left to chance. From a regulatory standpoint, that’s a weak position to defend.

Robustness isn’t something you add at the end

This is where a lot of organizations still get into trouble. Robustness is often treated as something you confirm near the end of development, almost as a final checkbox before validation. That’s too late if the method was never built on a solid understanding of variability in the first place. If you want a method to stand up over time, you need to understand what could make it drift, what could make it fail, and what could cause it to behave differently across analysts, instruments, materials, or sites.

This work belongs in development, and if it’s not done early, it usually has to be done later—while under pressure. You start seeing signals: precision drift, unexpected system suitability failures, repeat investigations, or borderline results. That’s exactly the situation regulators don’t want to see. If variability was understood earlier, many of those downstream questions become easier to answer, and some of them never come up at all.

Better method design starts with understanding variability

So, what does better design look like? It starts with practical questions:

• Where can variability enter this procedure?
• Where are the manual steps?
• Where are the sensitive conditions?
• Where could sample preparation go wrong?
• Where could chromatographic behavior change?
• Where might hardware, software, documentation, or human interaction influence the result?

Asking these questions early and adopting a structured, risk-based development approach is vital to understanding where variability can arise, which factors are most likely to affect method performance, and how the procedure can be designed and controlled to support reliable performance across its lifecycle, in line with the principles of ICH Q14 and USP <1220>.^2-4

This means mapping the workflow, identifying the factors that can influence the reportable result, and evaluating which of those factors are most likely to matter.⁴ The method can then be designed either to control those factors or to build a scientific understanding of their impact. That’s how the discussion moves from “the method seems to work” to “we understand why it works, and where it is vulnerable”. Those are very different positions when a method has to be defended under audit scrutiny.

A trial-and-error approach isn’t enough anymore

A lot of methods are still developed with a “one factor at a time” mindset. You adjust something, see if it looks better, adjust something else, and see if it improves again. That may get you to a usable method, but it often leaves a limited understanding of how the variables interact and where the real edges of performance are. The real problem is that you can end up with a method that looks acceptable under one set of conditions but is much less well-understood than people assume.

That matters later. When a method change or adjustment is needed, the question is not just whether the change can be made. The question is whether it can be justified scientifically. If the development work didn’t generate enough knowledge, that becomes much harder. You’re left with assumptions, opinions, and incomplete rationale, and those don’t hold up well in inspections. A systematic development approach makes that justification much easier.²

The real goal is methods that are defensible by design

One of the biggest benefits of strong development is that it reduces ambiguity later. When variability appears, you are in a much better position to ask the right question: Is this coming from the method, the sample, or the process?

Without that foundation, organizations often spend time chasing the wrong root cause. They tweak the method when the real issue is upstream. They retrain analysts when the real issue is design related. They treat repeated signals as isolated events instead of seeing them as signs of a broader weakness in the method.

The takeaway is straightforward. If you want methods that stand up to audit scrutiny, don’t treat audit-readiness as something you add later. Build it into the design.^2,3 Build in the understanding of variability. Build in the scientific rationale. Build in the control strategy.^2-4 Build in enough knowledge that, when questions come later, you aren’t guessing—you are explaining.

How can Waters help you?

Waters supports a more structured, risk-based approach by combining instrumentation, scalable chemistries, integrated informatics, and expert services to help laboratories design workflows that are scientifically justified, traceable, and defensible from the start.⁵

Waters positions this approach around lifecycle-oriented analytical design, aligned with ICH Q9 and ICH Q14, so teams can make better risk-based decisions, strengthen control, and support consistent method performance over time. Professional Services, Software Compliance Services, Instrument Qualification Services, and Analytical Services can then help labs deploy, validate, qualify, transfer, and maintain those approaches in a way that supports inspection-readiness across the method lifecycle.

In the end, that’s what strong method development should deliver: not just a passed validation study, but a method that’s robust, controlled, and scientifically defensible across its lifecycle. From a regulatory perspective, that’s what long term audit readiness really looks like.

Special thanks to Peter Baker, President, Live Oak Quality Assurance LLC, for generously sharing the regulatory insights and practical perspectives from the webinar series that informed this article.

To hear Peter Baker’s perspectives on Managing Method Variability in full, watch the webinar series.

References

1. Baker, P. (2025). Webinar series Managing Method Variability: A Foundation for Risk-Based Change.

2. International Council for Harmonisation. (2023). ICH harmonised guideline Q14: Analytical procedure development. Adopted 1 November 2023.

3. United States Pharmacopeia. (2021). <1220> Analytical Procedure Life Cycle. USP–NF. Rockville, MD: United States Pharmacopeial Convention.

4. International Council for Harmonisation. (2023). ICH harmonised guideline Q9(R1): Quality risk management. Adopted 18 January 2023.

5. Waters web page: Audit Ready Labs with Risk Based Quality Control.

With capabilities like these, it’s tempting to ask a simple question: Does chromatography still matter as much as it used to?

The short answer is yes.

The longer—and more important—answer is that chromatography has never been more critical to clinical confidence.

Analytical sensitivity can’t fix a poor separation

Advances in MS have fundamentally changed what laboratories can measure. But, no matter how sensitive an MS detector becomes, it still depends on what is delivered to it. The mass spectrometer signal represents the combined effects of the analyte and co‑eluting matrix components during ionization.

Clinical samples such as plasma, serum, urine, and hair are inherently complex. Endogenous compounds, metabolites, salts, and phospholipids all compete for ionization. When chromatography fails to adequately separate target analytes from this background, the result is familiar to anyone running LC‑MS in a clinical environment — ion suppression, unstable quantitation, and results that are difficult to trust.

More analytical sensitivity does not remove these effects — it can actually amplify them. Without robust chromatography, increased analytical sensitivity simply means detecting variability more clearly.

Chromatography is not just the ‘front end’

Chromatography is often described as the front end of the LC‑MS workflow, but that framing understates its importance. In practice, chromatography defines:

• Which compounds reach the ion source together
• How consistently analytes elute over time
• How stable peak shape and retention times are across long runs
• How reproducible quantitation is from day to day

In other words, chromatography doesn’t just prepare the sample for MS detection — it establishes the conditions under which the mass spectrometer can perform reliably.

This is especially important in clinical workflows, where assays must be stable across thousands of injections, multiple analysts, and extended operating hours.

The role of UHPLC in modern clinical LC‑MS

UltraHigh Performance Liquid Chromatography (UHPLC) has become a key enabler of reliable clinical LC-MS workflows. Higher efficiency separations deliver narrower, better-defined peaks, which support both chromatographic resolution and mass spectrometry response.

Narrower peaks don’t just improve separation—they help maximize MS signal, reduce coelution, and improve signal to noise. Just as importantly, modern UHPLC systems are designed to deliver this performance consistently, not just under ideal conditions.

For clinical laboratories, that consistency matters more than theoretical peak capacity. Reproducibility, retention time stability, and robustness over long sequences directly influence assay validity and confidence in reported results.

Why clinical labs have different chromatography needs

Not all UHPLC systems are created with clinical use in mind. Research environments often prioritise flexibility and one-off performance, while clinical laboratories operate under very different pressures.

Clinical chromatography must deliver:

• Stable retention times across long sequences
• Robust injector performance over thousands of injections
• Low carryover between high and low concentrations
• Predictable behaviour across shifts, analysts, and instruments
• Minimal intervention to maintain uptime

In these settings, chromatography is not evaluated by how it performs on a good day, but by how reliably it performs every day. It can often be said that in clinical labs: the most exciting result is the one that never changes.

Better chromatography reduces operational risk

When chromatography is stable and reproducible, the benefits extend well beyond analytical performance.

Reliable separations reduce the frequency of failed runs, reanalysis, and troubleshooting. This improves throughput, protects turnaround times, and reduces stress on staff. Over time, it also supports method longevity, helping validated assays remain fit-for-purpose longer.

From a quality perspective, consistent chromatography simplifies method validation, performance trending, and audit-readiness. Variability in chromatography often becomes variability in compliance — and that is a risk that clinical laboratories cannot afford.

Confidence comes from control, not complexity

UHPLC is sometimes perceived as introducing additional complexity into clinical workflows. The opposite is true when systems are designed for regulated environments.

Well-engineered UHPLC platforms provide tighter control over solvent delivery, sample introduction, and separation efficiency. That control translates into predictability—and predictability is the foundation of analytical confidence.

When chromatography behaves consistently, laboratories spend less time compensating for variability downstream, whether that’s through data review, repeat analysis, or investigation of unexplained trends.

Chromatography is the foundation of analytical confidence

Speed and analytical sensitivity are important. But in routine clinical LC‑MS, reliability at scale is what truly determines success.

Even as mass spectrometry continues to advance, chromatography remains the factor that decides whether results are trustworthy, repeatable, and defensible. It determines how well analytical sensitivity is translated into actionable clinical data.

In modern clinical diagnostics, chromatography is not an accessory to mass spectrometry. It is the foundation on which analytical confidence is built.

Waters pioneered UHPLC and has spent more than 20 years refining it for real-world analytical demands.

See how the ACQUITY UPLC I-Class PLUS IVD System brings that legacy into today’s clinical LC-MS labs.

MaxPeak Premier Oligo OBD Columns provide a powerful solution for these workflows, now expanded to include 19mm ID formats.

These columns reduce non-specific adsorption, improve recovery, and enable consistent scalable purification from analytical to preparative workflows.

Addressing the unique challenges of oligonucleotide purification

Unlike small molecules or even peptides, oligonucleotides often exhibit:

• Strong interactions with metal surfaces due to phosphate groups
• Significant structural similarity between impurities and target sequences
• Sensitivity to method conditions that can impact recovery and purity

These factors frequently result in non-specific adsorption (NSA), poor recovery, and compromised resolution, especially during scale-up.

For oligo workflows, where isolating sufficient material for characterization or downstream use is critical, these challenges translate directly into lost productivity, wasted samples, and uncertainty in results.

Introducing columns designed for scalable oligo purification

MaxPeak Premier OBD Prep Columns extend Waters inert column technology into preparative-scale purification, enabling scientists to bridge the gap between analytical method development and purification workflows.

With the introduction of 19 mm ID columns, users can now scale to higher load capacities while maintaining performance consistency and recovery, which is critical for oligonucleotide applications that require larger material quantities.

Key capabilities include:

• Predictable scale-up from analytical (2.1 mm) to preparative formats (10 mm →19 mm)
• Improved recovery of metal-sensitive analytes such as oligonucleotides
• Reduced non-specific adsorption, minimizing sample loss and improving detection
• Efficient purification workflows without the need for column passivation  

Why do 19 mm columns matter for oligo workflows?

While 10 mm preparative columns are widely used, the addition of 19 mm ID columns expands capabilities for oligo purification, particularly when you need to:

• Scale production for preclinical or analytical characterization
• Increase load capacity for low-level or difficult-to-isolate targets
• Reduce the number of injections required for purification

This is especially important for oligonucleotides, where low recovery or repeated purification cycles can significantly impact timelines and cost.

The 19 mm platform enables:

• Higher throughput purification with fewer runs
• Consistent performance at scale
• Confidence in isolating even low-abundance oligo species

Differentiating oligos from small molecules and peptides

Although MaxPeak Premier OBD Columns support a wide range of applications, including small molecule and peptide purification, their value is particularly pronounced for oligonucleotides, which are negatively charged and more prone to metal-surface interactions/non-specific adsorption. 

MaxPeak Premier Technology greatly reduces these surface interactions, enabling cleaner separations and improved recoveries across complex oligo mixtures.

A complete OBD portfolio for flexible workflows

The MaxPeak Premier OBD Column portfolio supports a full purification workflow, including:

• Analytical-scale columns for method development
• 10 mm prep columns for initial scale-up
• 19 mm prep columns for higher-throughput purification

Standard reversed-phase chemistries (e.g., BEH C₁₈ 130 Å and BEH C₁₈ 300 Å Columns) provide flexibility to tailor separations for different oligo modalities and impurity profiles. This continuity allows scientists to scale directly from optimized analytical methods without redevelopment, reducing risk and accelerating timelines.

Enabling confident oligo purification at scale

For scientists working in oligonucleotide research, development, and manufacturing, the ability to achieve the following is essential:

• Resolve impurities effectively
• Recover sufficient material for downstream analysis
• Scale methods predictably without rework

MaxPeak Premier OBD Columns, especially with the addition of 19 mm formats, deliver on these needs by providing an inert, scalable, and high-performance purification solution.

By reducing non-specific adsorption and enabling seamless scale-up, these columns enable researchers to move from discovery to production with greater confidence, efficiency, and success.

Learn more about Waters oligonucleotide purification solutions.

Additional resources:

MaxPeak Premier OBD Columns

Purifying Problematic Compounds by RP-LC: Simplified Workflows for Better Outcomes with Inert Preparative Columns (Webinar)

Purifying Oligonucleotides: High-Efficiency Prepative Chromatography to Improve Yields and Turnaround Time (Guidebook)

A recent Journal of Pharmaceutical Sciencesstudy by Prof. Susumu Uchiyama and colleaguesat the University of Osaka (Japan), in collaboration with Waters scientists, addresses this challenge by integrating analytical anion-exchange chromatography (AEX) with orthogonal tools including charge detection mass spectrometry (CDMS), mass photometry, LC–MS/MS peptide mapping, and genome integrity assays. Among these, CDMS is pivotal for resolving degradation mechanisms that are otherwise obscured.

Why this study matters

By anchoring chromatographic and spectrometric observations to particle-level measurements, this work demonstrates how CDMS enables confident interpretation of forced degradation data and provides practical guidance for formulation optimization and rAAV quality control.

The core problem: Forced degradation masks multiple pathways

Forced degradation studies are widely used to probe rAAV stability, but similar analytical readouts can originate from fundamentally different molecular failure modes, raising key unanswered questions:

• Which molecular mechanisms underlie changes in AEX retention time and peak area?
• How do pH and temperature redirect rAAV degradation pathways?
• Which degradation processes most strongly impact potency and infectivity?

Why are conventional analytical methods not enough

While analytical AEX is highly sensitive to surface charge changes, interpretation under stress conditions is limited by:

• Similar chromatographic shifts arising from deamidation, aggregation, adsorption, or genome loss
• Mass-averaging techniques that obscure coexisting particle populations
• Increased overlap between empty and full particles as degradation progresses

How does CDMS solve the problem

CDMS overcomes these limitations by directly measuring the mass and charge of individual viral particles. In this study, CDMS revealed that:

• Charge shifts observed by AEX correlate directly with capsid deamidation at the particle level
• Empty and full rAAV particles respond differently to accelerated stress
• Structural rearrangements can counterbalance surface charge changes in genome-containing particles

Distinct degradation pathways across pH conditions

Integration of CDMS with orthogonal techniques revealed sharply distinct degradation regimes:

• Neutral and basic conditions promote deamidation, aggregation, and nonspecific adsorption
• Acidic conditions trigger genome fragmentation, capsid protein cleavage, and rapid titer loss
• A citrate buffer at pH 5.5 provides exceptional thermal stability despite elevated temperature stress

Read the full study, “Forced degradation analysis of recombinant adeno-associated virus serotype 8 based on analytical anion exchange chromatography coupled to orthogonal characterization,” and see how CDMS enhanced rAAV analysis.

A recent Nature Communications study by Prof. Siavash Vahidi and colleagues at the University of Guelph (Canada), in collaboration with Waters scientists, addresses this challenge by integrating charge detection mass spectrometry (CDMS) with native MS, hydrogen-deuterium exchange mass spectrometry (HDX-MS), and nuclear magnetic resonance (NMR). Among these techniques, CDMS is pivotal for resolving the structural heterogeneity that previously obscured the functional mechanism of the bacterial proteasome activator Bpa.

The core problem: Structural heterogeneity masks function

Bpa is a large, ring-shaped regulatory particle that activates the mycobacterial 20S proteasome. Although prior studies identified the dodecamer as the active form, key questions remained unresolved:

• Does Bpa exist exclusively as a dodecamer under physiological conditions?
• How dynamic is Bpa oligomerization in solution?
• Which oligomeric state is responsible for substrate engagement?

These questions arise because Bpa exists as a heterogeneous mixture of dimers, tetramers, and dodecamers that interconvert in a temperature-dependent and reversible manner. Conventional tools such as size-exclusion chromatography (SEC) and native MS struggle to accurately quantify these coexisting species due to charge-state overlap and mass-dependent detection bias.

Why is conventional MS not enough?

While native MS revealed multiple Bpa oligomeric states, interpretation was limited by:

• Overlapping charge-state distributions for high-mass complexes
• Under-representation of large assemblies
• Apparent inflation of low-abundance species

As a result, it remained unclear whether Bpa fully assembles into its functional form under activating conditions.

How does CDMS solve the problem

CDMS overcomes these limitations by directly measuring the mass and charge of individual ions, enabling unbiased analysis of heterogeneous, high-mass protein assemblies. In this study, CDMS demonstrated that under physiological conditions:

• Bpa exists almost exclusively as a fully assembled dodecamer
• Signals from dimers and tetramers disappear

This result resolves inconsistencies seen with conventional MS and confirms that the dodecamer is the dominant, biologically relevant species.

From assembly to function

With the active oligomeric state firmly established by CDMS, the authors could confidently connect structure to function. Supporting techniques revealed that:

• Only dodecameric Bpa engages substrates
• Substrates are recognized via short hydrophobic motifs in disordered regions
• Multiple substrates bind per Bpa ring

Together, these findings show that temperature-dependent assembly acts as a molecular switch that controls when Bpa can deliver substrates to the proteasome.

Read the full study, “Structural heterogeneity and substrate engagement mechanism of the bacterial proteasome activator Bpa,” and learn more about the advantages of CDMS.

A recent Nature Communications study led by Dr. Ronit Mazor and colleagues at the U.S. Food and Drug Administration (FDA), in collaboration with Waters scientists, addresses this challenge by integrating computational immunoengineering with experimental validation. The study introduces a systematic framework for identifying and modifying CD4⁺ T-cell epitopes in the AAV9 capsid while preserving vector function.

Why this study matters

This work provides a compelling proof-of-concept for rational deimmunization of viral vectors. By integrating computational prediction with detailed experimental validation, the study establishes a scalable framework for improving the safety, durability, and re-dosing potential of AAV-based gene therapies.

The core problem: Capsid-driven T-cell responses limit gene therapy

Key questions driving this study included:

• Which regions of the AAV9 capsid act as immunodominant CD4⁺ T-cell epitopes?
• Can these epitopes be disrupted without compromising capsid integrity or transduction efficiency?
• How can candidate mutations be identified systematically rather than by trial-and-error?

Why are conventional strategies not enough

Previous approaches to reducing AAV immunogenicity are limited by:

• Incomplete control over T-cell–mediated immune recognition
• Dependence on naturally occurring non-immunogenic serotypes
• Lack of scalable, systematic methods for epitope redesign

How does computational epitope engineering solve the problem

Using the Epitope Modification and MHC Prediction (EMMP) pipeline, the study demonstrated that:

• A CD4⁺ T-cell epitope centered on residue R312 is immunodominant in the AAV9 capsid
• EMMP can systematically evaluate mutations predicted to reduce MHC class II presentation
• R312H and R312Q emerged as leading candidates for experimental validation

From prediction to biological validation

Experimental testing revealed that:

• The R312Q mutation abolishes CD4⁺ T-cell activation and cytokine production
• Anti-AAV9 antibody responses are significantly reduced
• Vector biodistribution is preserved with only modest reductions in transduction efficiency

Read the full study, “Integrated computational and experimental immunoengineering of adeno-associated virus capsid T-cell epitopes in mice,” and learn more about the latest developments in AAV analysis.