The validity of a
specific method proposed to a particular analysis should be demonstrated in
laboratory experiments using samples or standards that are similar to unknown
samples analyzed routinely. The preparation and execution should follow a
validation protocol which is pre-documented, preferably written in a step-by-step
instruction format. Possible steps for a complete method validation are listed
validation protocol, an operating procedure or a validation master plan
for the validation.
For a specific
validation project define owners and responsibilities
validation project plan.
application, purpose and scope of the method.
performance parameters and acceptance criteria.
performance characteristics of equipment.
e.g. standards and reagents for purity, accurate amounts and sufficient
parameters or/and acceptance criteria if necessary.
internal (and external) validation experiments.
for executing the method in the routine.
criteria for revalidation.
and frequency of system suitability tests and/or analytical quality control
(AQC) checks for the routine.
validation experiments and results in the validation report.
procedure assumes that the instrument has been selected and the method has been
developed. Instrument should meets criteria such as ease of use; ability to be
automated and to be controlled by computer systems; costs per analysis; sample
throughput; turnaround time; and environmental, health and safety requirements.
is not an individual’s responsibility. Successful acceptance of the validation
parameters and performance criteria, by all parties involved, requires the
cooperative efforts of several departments, including analytical development,
QC, regulatory affairs and the individuals requiring the analytical data. The
operating procedure or the Validation Master Plan (VMP) will clearly define the
roles and responsibilities of each department involved in the validation of
The scope of the method and its validation criteria are defined
early in the process. These include the questions like what analytes should be
detected, what are their expected concentration levels, what are the sample
matrices, are there any expectation for interfering substances, and, if so,
should they be detected and quantified or should not they, are there any
specific legislative or regulatory requirements for the validation, would
information be quantitative or qualitative, what are the required detection and
quantitation limits for the selected method, what is the expected concentration
range, what precision and accuracy is expected for the selected method, which type
of equipment should be used for the analysis, is the method is narrowed for one
specific instrument, or should it be used by all instruments of the same type,
will the method be used in one specific laboratory or should it be applicable
in all laboratories at one side or around the globe, what skills do the anticipated
users of the method have etc.
the method’s performance should be based on the intended use of the method.
Validation of all analytical parameters that are available for a specific
technique is not always necessary. For example, if the method is to be used for
qualitative trace level analysis, there is no need to test and validate the
method’s limit of quantitation, or the linearity, over the full dynamic range
of the equipment.
The method scope
should also include the different types of equipment and the locations where
the method will be run. For example, if the method is to be run on a specific
instrument in a specific laboratory, there is no need to use instruments from
other vendors or to include other laboratories in the validation experiments.
In this way, the experiments can be limited to what is really necessary.
Below table gives examples of which parameters
might be tested for a particular analysis task.