What Is the Difference Between HPLC and LC-MS?
Short answer
Both use liquid chromatography to separate a sample into its components. The difference is the detector. HPLC usually measures each compound with a UV detector, which is accurate and economical for potency against a label claim. LC-MS sends the separated compounds into a mass spectrometer that measures their mass, so it can confirm identity, find unknowns and detect far smaller amounts.
The shared part: liquid chromatography
In both techniques, a dissolved sample is pumped through a packed column. Compounds interact with the column packing differently, so they exit (elute) at different times (Shimadzu). The time a compound takes to come out is its retention time. Up to this point, HPLC and LC-MS are the same (NCBI StatPearls).
The difference: what happens at the detector
HPLC-UV shines ultraviolet light through the liquid as it leaves the column. Each compound that absorbs UV shows up as a peak. The peak’s area, compared with a reference standard, tells you how much is present. It is robust, precise and the standard method for potency and purity testing of drug products.
LC-MS ionizes the compounds and measures their mass-to-charge ratio. That adds a second, independent identity check (molecular mass) and much greater sensitivity. LC-MS/MS goes further: it selects one ion, breaks it into fragments and measures those, which is highly selective and widely used for confirmation testing in toxicology (Maurer, PubMed; PMC).
| HPLC (UV) | LC-MS / LC-MS/MS | |
|---|---|---|
| Separation | Liquid chromatography | Liquid chromatography |
| Detection | UV absorbance | Mass-to-charge ratio |
| Identity evidence | Retention time vs reference standard | Retention time plus molecular mass and fragments |
| Sensitivity | Good for main ingredients | Much higher; trace levels |
| Best for | Potency, purity, routine release | Identity confirmation, unknown peaks, trace analysis, toxicology confirmation |
| Relative cost | Lower | Higher |
Which one do you need?
- “Does my product contain the labeled amount?” HPLC potency testing is usually the right answer. See potency testing.
- “Is this really the compound on the label?” HPLC identity against a standard, with LC-MS when mass confirmation is needed.
- “What is this extra peak?” LC-MS can help identify unknowns.
- “Is a drug present at very low levels?” LC-MS or LC-MS/MS. See toxicology testing.
Many projects use both: HPLC for routine potency on every batch, and LC-MS when a result needs confirmation or an unexpected peak needs explaining. Not sure? Tell us your question and we’ll recommend the method. Our in-depth HPLC vs LC-MS guide covers more, and you can read about our HPLC testing lab and LC-MS testing services.
Related questions
Is LC-MS more accurate than HPLC?
LC-MS is more specific and sensitive, but for measuring a known main ingredient against its label, a validated HPLC-UV method is accurate and more economical.
Can HPLC identify an unknown compound?
Not on its own. HPLC-UV matches retention times to known standards. Identifying an unknown usually needs mass spectrometry such as LC-MS.
What does LC-MS/MS mean?
Tandem mass spectrometry: one analyzer selects an ion, it is fragmented, and a second analyzer measures the fragments, giving a highly selective fingerprint.
Does Renew Lab Group offer both?
Yes. Our Houston lab runs HPLC and LC-MS. Call 936-379-5515 or email info@renewlabgroup.com for a quote.
Talk to the lab about HPLC or LC-MS testing
Tell us what you need tested and we’ll recommend a method and send a quote. Contact us at 936-379-5515 or info@renewlabgroup.com for current pricing, turnaround and sample requirements. Samples can be dropped off at our lab at 6001 Central Crest, Houston, TX 77092.
Sources
Researcher resources
- Shop Bacteriostatic and Sterile Water
- View Our Certificate of Analysis
- Free Reconstitution Calculator
- Compare BAC Water Products
Keep reading
- What Is a Beyond-Use Date (BUD)?
- Can You Use Tap Water in an Ultrasonic Diffuser?
- What Is ICP-MS Testing?
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