Hi, I think it depends on the concentrations of the compounds; At our Lab., we did usually spotted 1-5 microliter (using Linomat or Nanomat), I think it is nicer to spot smaller volume by making more concentrated solutions compare to spot more volume (> 5 microliter) by using diluted solutions.

There is some standard. 5 micro lit from 10 mg/ml, 10 micro lit from 1 mg/ml in case of extract or compounds and 10 micro lit from 100 mg/ml of raw powder.

Our linomat V was set to release 5 micro liter per application and this is sufficient also. If you are not getting proper results or very faint spots, you should increase the concentration of the sample in the solution.

That should help.

It depends on your sample that your recover,but 5 micro liter will be enough not to overload the plate.

Not more than 100 microgram for pure compund and not more than 1 mg for extract for analytical purpose. For preparative 10 times more than analytical.

Hi, based on a method collection provided by the HPTLC association, 1-10 microliters of samples and references can be applied, which 2-4 microliters were commonly used. Previously, I used 10 microliter of 10 mg/ml of a sample for profiling. You may find this method in www.hptlc-association.org or googling: method collection hptlc (a pdf file can be downloaded)