I need to measure the reducing and total sugar of my sample .. I have applied DNS assay for reducing sugar and phenol sulphuric assay for the the total sugar .. the problem I face regarding the standard ..for the first standard .. I v prepared stock solution contain 100mg of glucose /100ml..later I worked on the working solution by diluting 10 ml of stock solution into 100 ml volumetric flask .. the range of serial was from 0-100 micg that prepared by adding .1_.2_.3_.4_.5_.6_.7_.8_.9 _1 ml of glucose and topped up with water to get 1ml final volume ...when i have done the experiments the concentration seems to be near to each other and i got the same colour for all the standard beside that , the highest concentration of glucose which is 100 micg/ml was so light comparing by my sample.. so i have run another serial dilution from the stuck solution by adding 1 ml of stuck solution to 1 ml of water to get 500 micg/ml then i continue dilution the highest concentration to get 250-125-62,5-31.2-15.6-7.8 micg/ml.. but also the change of colour just take place in the highest concentration which is 500micg/ml and i got the same colour for the rest of dultuin tubes .. my sample as well has reading that is higher than the highest concentration (500), i believe that my sample will need to be diluted more so that i can get the proper reading but pls any recommendation or notice for the standard?
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