How to calculate LOD & LOQ in HPLC Validation Method
Answer Posted / bhupalreddy
Limit of Detection (LOD):
• Based on visual limitation
– Visual evaluation may be used for non-instrumental
methods but may also be used with instrumental methods.
– The detection limit is determined by the analysis
of samples with known concentrations of analyte and by
establishing the minimum level at which the analyte can be
reliably detected.
• Based on signal-to-noise
– This approach can only be applied to analytical
procedures which exhibit baseline noise.
– Determination of the signal-to-noise ratios is
performed by comparing measured signals from samples with
known low concentrations of analyte with those of blank
samples an establishing the minimum concentration at which
the analyte can be reliably detected. A signal-to-noise
ratio between 3 or 2:1 is generally considered acceptable
for estimating the detection limit.
• Based on the standard deviation of the response
and the slope
– The detection limit = 3.3 s / S
– Where s is the standard deviation of the response
and S is slope of the calibration curve.
– The estimate of S may be carried out in a variety
of ways, for example:
• Based on the standard deviation of the blank
• Based on the calibration curve
Limit of Quantification (LOQ):
• Based on visual limitation
– Visual evaluation may be used for non-instrumental
methods but may also be used with instrumental methods.
– The quantification limit is determined by the
analysis of samples with known concentrations of analyte
and by establishing the minimum level at which the analyte
can be quantified with acceptable accuracy and precision.
• Based on signal-to-noise
– This approach can only be applied to analytical
procedures which exhibit baseline noise.
– Determination of the signal-to-noise ratios is
performed by comparing measured signals from samples with
known low concentrations of analyte with those of blank
samples an establishing the minimum concentration at which
the analyte can be reliably quantified. A typical signal-to-
noise ratios is 10:1.
• Based on the standard deviation of the response
and the slope
– The quantification limit = 10s / S
– Where s is the standard deviation of the response
and S is slope of the calibration curve.
– The estimate of S may be carried out in a variety
of ways, for example:
• Based on the standard deviation of the blank
• Based on the calibration curve
Is This Answer Correct ? | 21 Yes | 4 No |
Post New Answer View All Answers
How we can identify process related and degradation impurity in single method with short period?
function of detecter in hplc ,gc and spectroscopy? function of carrier gas in gc?
what is the extinction coefficient for Indomethacin or at 319nm wave length.
How we performed the force degradation for drug substance, is any specific guideline is available for each parameter(Acidic, basic, oxidation,heat)? what conditions you mentained for above parameters.
what is turbidimetric titration?Give 2 examples.
Why use only methanol,used determinationof moisture content not use other solvents
what is %labelled amount in content uniformity of dosage unit and its calculation?
What is the principle of Thermal conductivity detector and FID?
is it necessary to do HPLC calibration at wavelength 315nm if we are doing analysis at this wavelangth
effect of pore size, pore volume, partical size, column length, carbon load on retention time? what is carbon load? what is the use?
If vendor having more imp than monograph then how to proceed? and how to set spec?
what type of question will ask in the interview of lab chemist.
how to develop the icp ms method? Application of icp ms?
what is difference between UV - VISIBLE MODEL NO like 1600,1601,1700 etc ? plz explain me
when we talk about change in entropy we consider total entropy means of surround +entropy of system but when we talk about change in Gibss free energy we consider entropy of system.explain with reason.