[Eogle]

Should be simple, but I always have trouble with this type of calculation.  The CRA method for the determination of SO2 has the calculation for the amount of SO2 (in ppm) as :

Net Titer x N Iodine solution x 0.032 x 10⁶
     Sample Weight

A method probably drawn from this has shortened the equation to Net titer x 64, because they are using 0.02N iodine.  Since the method spells out mixing 30 grams of starch in 150 mL of water, filtering and using 50mL of filtrate
I'm thinking that the equation is really:
Net Titer x 0.02 x 0.032 x 10⁶
     (30/150) x 50

But what if I already have the starch in slurry form.  I filter it and use 50 mL of filtrate.  What is my sample weight really?  If I weigh out 200 grams of slurry is the equation:
Net Titer x 0.02 x 0.032 x 10⁶
     (50/100)

That doesn't seem right.  Can anyone help me fix this?

[AWK]

Since the method spells out mixing 30 grams of starch in 150 mL of water, filtering and using 50mL of filtrate

If you do not dilute filtrate to exactly known volume (eg. 250 ml measuring flask) you should assume mass of titrated sample  as mass_sample*50/150 but this is for such high concentration of starch rather very crude approximation (I assume solution contains SO₂, but starch after filtration still will contain water, hence the volume will be lower than 150).
Moreover your equation is mathematically odd (though correct) using titer im mL and mass of titrated sample in grams.