An HPLC result is a peak area against a calibration, and everything that makes it meaningful sits outside the chromatogram: which method was used, whether that method was validated in your matrix, what the peak was identified against, and what the laboratory was accredited to do. Buying the analysis rather than the instrument is the right answer far more often than the instrument market implies, and this page is about what you are actually buying when you do.
What HPLC testing services quote for, and what HPLC testing leaves outside the price
A per-sample figure normally covers the injection, the data and a report against a method the laboratory already holds. It does not cover developing a method for a matrix they have not analysed, the reference standard your analyte needs, an extraction beyond a stated simple case, or a turnaround shorter than the standard one. Two quotations that differ by a factor of three are usually not disagreeing about the run: one is assuming an existing validated method and the other is pricing in building it. Ask which, and the numbers converge.
An HPLC lab test against running the separation yourself
The instrument is the smaller half of the cost. Columns, solvent of the right grade, reference standards, the analyst's time and a service contract are continuous, and a method you do not yet have is a project measured in weeks. Below a few hundred samples a year an outside laboratory is normally cheaper and always faster to start. Above that, and where the result feeds a decision made repeatedly, bringing it in house starts to pay, and the threshold is worth working out on your own sample numbers rather than taking from a vendor's model.
Comparing HPLC services against an HPLC service contract
Two different things are sold under nearly the same words, and enquiries routinely conflate them: analysis, where a laboratory runs your samples, and maintenance, where an engineer keeps your instrument qualified. If you are buying analysis, ask about scope of accreditation, method validation status and reporting. If you are buying maintenance, ask about response time, what parts are included and whether the visit includes the performance qualification that a regulated environment needs.
What an HPLC analysis service can and cannot identify
Retention time plus a detector response is a strong presumption and not an identification. A diode array adds a spectrum, which raises confidence and still does not distinguish close analogues; a mass detector is what turns a presumption into an identification. If the question is how much of a known compound is present, chromatography with a conventional detector is the right and cheaper answer. If the question is what the unknown peak is, the enquiry needs a mass detector and should say so, because a laboratory answering the cheaper question will report an unidentified peak and be right to.
HPLC testing equipment the laboratory supplies, and the part you do
The sample is yours and it is where most failures start. Sample stability between collection and injection, the container, the solvent it is dissolved in and whether it has been filtered all change the result, and none of them is the laboratory's to control. Agree the sample condition, the volume and the storage in writing before the first batch, and send a blank of your own matrix with it. That one extra vial answers more questions than any discussion of the instrument.
Questions people ask about hplc test
Why do two laboratories quote so differently?
Usually because one holds a validated method for your matrix and the other is pricing the development. Ask each whether the quotation includes method development, reference standards and sample preparation.
Does a peak at the right retention time identify my compound?
It is a presumption, not an identification. A spectrum from a diode array strengthens it; only a mass detector settles it. Say which question you are asking when you send the enquiry.
When is it worth buying the instrument?
When sample numbers run to several hundred a year and the method already exists or is straightforward. The capital is the smaller half: columns, standards, solvent grade, analyst time and the service contract are continuous.