Methods & instrumentation

Techniques in scope, and what each one can establish.

Capability is not the same as accreditation. This page describes the techniques the laboratory operates; any accreditation, registration or validation status applicable to a specific engagement is stated in the scope agreement and is available upon request.

Technique	Primary use	Typical reporting	Interpretation notes
RP-HPLC UV/DAD	Chromatographic purity, related substances	% area at a stated wavelength	Separation on a reversed-phase column with diode-array detection. Establishes the relative proportion of the chromatographic profile; it is not a mass balance and does not detect species without a chromophore at the monitored wavelength.
UHPLC	High-resolution purity and assay	% area, % of label claim	Sub-2 µm particle separations used where resolution between closely eluting related substances is the limiting factor, or where throughput on a stability programme matters.
LC-MS / HRMS	Identity, accurate mass, impurity characterisation	Observed vs theoretical mass, conforms / does not conform	Chromatographic separation coupled to mass detection. High-resolution data supports elemental composition assignment; nominal-mass data supports identity confirmation only.
SEC-HPLC	Aggregation, high-molecular-weight species, fragments	% area	Separation by hydrodynamic size under non-denaturing conditions. Sensitive to mobile-phase composition, which is recorded with the result.
GC-MS / headspace GC	Residual solvents, volatile impurities	ppm per solvent	Volatiles are sampled from the headspace above the prepared sample. Only solvents included in the agreed target list are reported.
ICP-MS / ICP-OES	Elemental impurities, heavy metals	ppm or µg/g per element	Sample digestion followed by elemental determination. The element list is finite and is printed on the certificate; elements outside the list are not assessed.
NMR	Structural corroboration, isomer discrimination	Descriptive interpretation	Used as supporting evidence for identity assignments and for questions that chromatography and mass detection cannot resolve on their own.
FT-IR	Functional group and salt form corroboration	Spectral comparison, conforms / does not conform	Rapid comparison against a reference spectrum. Sensitive to physical form and sample preparation, both of which are recorded.
Karl Fischer	Water content	% w/w	Volumetric or coulometric depending on the expected level. Particularly relevant for lyophilised material where declared mass assumes a dry basis.
UV-Vis	Concentration, chromophore-based content	Absorbance, concentration	Fast concentration estimates using an established extinction coefficient. Non-specific, so it is used alongside a separative method rather than instead of one.
LAL (kinetic chromogenic)	Bacterial endotoxin	EU/mg or EU/container	Dilution scheme and inhibition or enhancement handling are recorded with the result, since both materially affect interpretation.
Bioburden / sterility	Microbial content	CFU/g, growth / no growth	Performed within agreed scope. Sample quantity requirements are confirmed before shipment; insufficient quantity is reported rather than extrapolated.

RP-HPLC UV/DAD

Chromatographic purity, related substances

Reports: % area at a stated wavelength

Separation on a reversed-phase column with diode-array detection. Establishes the relative proportion of the chromatographic profile; it is not a mass balance and does not detect species without a chromophore at the monitored wavelength.

UHPLC

High-resolution purity and assay

Reports: % area, % of label claim

Sub-2 µm particle separations used where resolution between closely eluting related substances is the limiting factor, or where throughput on a stability programme matters.

LC-MS / HRMS

Identity, accurate mass, impurity characterisation

Reports: Observed vs theoretical mass, conforms / does not conform

Chromatographic separation coupled to mass detection. High-resolution data supports elemental composition assignment; nominal-mass data supports identity confirmation only.

SEC-HPLC

Aggregation, high-molecular-weight species, fragments

Reports: % area

Separation by hydrodynamic size under non-denaturing conditions. Sensitive to mobile-phase composition, which is recorded with the result.

GC-MS / headspace GC

Residual solvents, volatile impurities

Reports: ppm per solvent

Volatiles are sampled from the headspace above the prepared sample. Only solvents included in the agreed target list are reported.

ICP-MS / ICP-OES

Elemental impurities, heavy metals

Reports: ppm or µg/g per element

Sample digestion followed by elemental determination. The element list is finite and is printed on the certificate; elements outside the list are not assessed.

NMR

Structural corroboration, isomer discrimination

Reports: Descriptive interpretation

Used as supporting evidence for identity assignments and for questions that chromatography and mass detection cannot resolve on their own.

FT-IR

Functional group and salt form corroboration

Reports: Spectral comparison, conforms / does not conform

Rapid comparison against a reference spectrum. Sensitive to physical form and sample preparation, both of which are recorded.

Karl Fischer

Water content

Reports: % w/w

Volumetric or coulometric depending on the expected level. Particularly relevant for lyophilised material where declared mass assumes a dry basis.

UV-Vis

Concentration, chromophore-based content

Reports: Absorbance, concentration

Fast concentration estimates using an established extinction coefficient. Non-specific, so it is used alongside a separative method rather than instead of one.

LAL (kinetic chromogenic)

Bacterial endotoxin

Reports: EU/mg or EU/container

Dilution scheme and inhibition or enhancement handling are recorded with the result, since both materially affect interpretation.

Bioburden / sterility

Microbial content

Reports: CFU/g, growth / no growth

Performed within agreed scope. Sample quantity requirements are confirmed before shipment; insufficient quantity is reported rather than extrapolated.

Scope vs accreditation

Two separate statements.

Scope

Scope is what the laboratory will determine for your sample: the analyte, the matrix, the technique, the reporting unit and the acceptance criteria, if any. Scope is agreed in writing before work begins and is reproduced on the certificate so that a reader can see exactly what was and was not covered.

Accreditation and registration

Any accreditation, registration, certification or method-validation status is a separate matter from capability, is specific to defined activities, and is only claimed where it genuinely applies. HDChroma states the applicable status for a given engagement in the scope agreement — available upon request, subject to scope — and does not imply it on this page.