by using chlorophyl meter

Arnon's method is widely used to measure chlorophyll content.

if you are using non destructive methods of measurement , a chlorophyll meter will do the job, if considering destructive methods extract the chlorophyll and measure by spectrophotometer

If you have an access to a spectrofluorimeter, you can measure extremely low amounts of chorophyll ( doesn't looks even green )in aqueous buffer supplemented with triton X100, no need of solant extraction !

you can also measure chlorophyll content by using SPAD

you can used spectrophotometer, determine chlorophyll a and b, the take total measurement.

Use Minolta SPAD-502 chlorophyll meter...