Query for Analytical Method pertaining to determination of Detergent in Swab samples

Dear All,
I’v been given task to develop a analytical method [Preferrably by UV] for determination of detergent in swab samples. Limit of Detergent is 3mg/swab.
In breif ,my validation plan is to plot calibration curve for Detergent [Lot.I. assumed as Standard] with 10 levels of Known concentration , ranging from 0.3mg to 6mg. To verify the variablity associated with Detergent composition & Random errors assocaited within the calibration curve, I plan to measure second set of standards[Prepared from Lot II of Detegent ranging from 0.3mg to 6mg], using the calibration plot prepared by Lot I of detergent.Tolerances to these known amount of standards is fixed as ±2.5%. Thereafter, the above calibration method will be locked for editing. The analytical method will have other parameters, such as LOD, LOQ, Recovery, Precision and Ruggedness.
In real time situation, Standard preparation (to the limit level) will be measured against the calibration curve, with same tolerances ± 2.5%, will be considered as System suitability. (ie). Standard preparation of 3mg will be prepared, when verified against the inbuilt method for detergent, it should provide concentration 2.925mg to 3.075mg. If obtained Standard concentration is within the desired limits specified , maximum six samples can be measured, after which a bracketting /Tailing standard is measured to verify the consistency of instrument at the end of analysis.
Kindly respond/ reply, if you are having any comments/query/issues which can arise in present situation /in near future, on the above explained methodology