Key Takeaways
HPLC is primarily a separation technique coupled to a detector.
LC-MS combines separation with mass-to-charge measurement.
HPLC chromatograms are useful for separation and relative quantitation under a defined method.
LC-MS adds molecular-mass information and can improve specificity when properly applied.
HPLC in one sentence
HPLC separates compounds and records detector response as components elute from a chromatographic column.
LC-MS in one sentence
LC-MS uses liquid chromatography for separation and mass spectrometry for mass-to-charge analysis.
What HPLC can show
An HPLC chromatogram can show retention times, peak areas, peak shapes, and separation between components. It can be highly useful for assessing chromatographic purity when the method is fit for purpose.
What LC-MS adds
LC-MS can associate chromatographic peaks with mass-to-charge information. For peptide research, that additional dimension can help assess whether an observed component is consistent with the expected molecular mass.
Why laboratories may use both
Analytical questions often benefit from orthogonal evidence. A chromatogram answers a separation-related question, while a mass spectrum provides mass-related information. FDA guidance recognizes combinations such as HPLC/MS as useful for specific identification.
Choosing the method
The appropriate technique depends on the analytical question, sample, required sensitivity, available instrumentation, and validated method. Analytical procedure development should be science- and risk-based and appropriate for the intended purpose.
Frequently Asked Questions
Which is better, HPLC or LC-MS?
Neither is universally better. They answer different questions, and LC-MS incorporates chromatographic separation plus mass-based detection.
Can HPLC determine molecular weight?
Standard HPLC by itself does not directly measure molecular mass. LC-MS adds mass-to-charge information.
Can LC-MS measure purity?
It can provide chromatographic and mass information, but purity calculations still depend on the analytical method, detector response, integration, and reporting approach.
NorthPep Research Note
NorthPep content is provided for educational and laboratory-research information. It is not medical advice and does not provide instructions for human or veterinary administration. Readers should follow applicable laws, institutional requirements, validated laboratory procedures, and appropriate safety practices.