Why Ultrapure Water Matters in HPLC Analysis — What Every Lab Should Know

High-performance liquid chromatography (HPLC) is one of the most widely used analytical techniques in modern laboratories. From pharmaceuticals and food safety to environmental testing and life sciences, HPLC plays a critical role in separating, identifying, and quantifying compounds in complex mixtures.

While much attention is often given to chromatography columns, solvents, and detectors, one essential component is frequently overlooked: the quality of the water used.

Why Water Quality Is Critical in HPLC

Water is used throughout HPLC workflows—not only as a component of the mobile phase, but also for sample preparation, blank solutions, and standard dilutions. Any impurities in water—be it ions, organic molecules, particulates, or microbes—can significantly affect analytical accuracy, reproducibility, and even the lifespan of your instrumentation.

Common Misconceptions About Laboratory Water

From our experience supporting laboratories, we’ve seen several recurring misunderstandings when it comes to water use in HPLC:

Myth 1: Deionized water is good enough
Even deionized water may still contain particulates, organic contaminants, or microbial growth. These can cause false peaks, noisy baselines, and inconsistent results.

Myth 2: Water can be produced in bulk and stored
Once ultrapure water is exposed to air, its quality deteriorates quickly. Electrical resistivity drops, and TOC (total organic carbon) increases, leading to baseline drift and signal noise.

Myth 3: Resistivity is all that matters
Resistivity measures ionic content, but TOC indicates organic contamination. Both are crucial for high-precision HPLC.

Myth 4: Bottled water is an acceptable alternative
Some bottled water may appear to meet basic water specs, but lacks consistency and traceability. Without proper water quality reports, bottled water carries significant risk for regulated or audit-sensitive labs.

HPLC Water Requirements — How Pure is Pure Enough?

For low-sensitivity analyses, basic water requirements are:

•Resistivity ≥ 1 MΩ·cm

•TOC ≤ 50 ppb

But in most advanced applications, only ultrapure water ensures reproducible, high-accuracy results:

•Resistivity ≥ 18.2 MΩ·cm (at 25°C)

•TOC ≤ 5 ppb

Filtered through 0.22 μm membrane to remove particulates and microbes

•Using substandard water can cause:

•Baseline drift and ghost peaks

•Peak tailing or splitting

•Column clogging

•Reduced detector sensitivity

•Shortened instrument lifespan

•Increased maintenance costs

Ultrapure Water Solutions for HPLC Labs

Hyperpurex’s laboratory-grade water systems are designed to meet the most demanding HPLC water requirements.

All models deliver:

Resistivity up to 18.2 MΩ·cm

TOC levels as low as <2 ppb

Bacteria <0.01 CFU/ml

Compliance with ASTM, GB/T, USP, EP, and JP standards