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
CAN WE DETERMINE THE PEAK PURITY IN GAS CHROMATOGRAPHY ANALYSIS?
Why we used in n-butyl acetate water content terminology while in ethyl acetate we used moisture content terminology?
For titration in anhydrous media with perchloric acide, if lack of titrator, Which indicator is been used for replacement. How calculate pH of test solution to choose suitable indicator?
Which are the diffrent grades of api in pharma?
how decide the clining method and cleaning method validation require for this perticular products?
Why only Copper standard is used to calibrate Atomic Absorption spectrophotometer?
iam usig ph buffers merk. manually how to prepare ?
for which product require to do content uniformity? what is limit of cu?
What is similarity factor and its use in api strength?
what is the structure of DOWEX-50
What is the formula for relative diffrence for standard solution in solution stability in validation?
Why we use potassium dichromate in uv calibration Exact reason behind it??
Which parameter require to do for analytical method equivalency?
How they found 1mL of K.F reagent is equivalent to 5mg of water and if we change the composition of K.F reagent, is it can neutralize more amount of water?
Loss of linearity in tkn analysis, possible reasons?