Hi there,
If the injection volume of the needle are limited to 5microlitre in hplc while injection volume of the specifications is 1000 microlitre. What should we do until that injection volume will be injected?
You will have to consider re-validation of this Analytical method after necessary changes are made. Generally, you can modify the dilutions of standard solution and sample solution so that the final concentration of analyte in 5 microliter of standard and sample solutions will be the same as that in 1000 microliter as per specification. If re-validation is satisfactorily conducted, then you can inject 5 microliters in to HPLC both the standard and sample solutions.