It's possible.  But the reference standard for Acetylsalicyclic Acid must be ultra-pure.  If you are a pharmaceutical manufacturer it must be a primary standard from the USP or EDQM.  As an example;

Assay preparation—Remove, as completely as possible, the contents of not fewer than 20 Capsules, and weigh accurately. Mix the combined contents, and transfer an accurately weighed quantity of the powder, equivalent to about 50 mg of aspirin, to a 50-mL volumetric flask containing 1 mL of a 1 in 50 solution of hydrochloric acid in methanol, add chloroform to volume, and mix. Transfer 5.0 mL of this solution to the column, wash with 5 mL and then with 25 mL of chloroform, and discard the washings. Elute into a 100-mL volumetric flask with about 10 mL of a 1 in 10 solution of glacial acetic acid in chloroform and then with about 85 mL of a 1 in 100 solution of glacial acetic acid in chloroform, dilute with the latter solvent to volume, and mix.

Procedure—Without delay, concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 280 nm, with a suitable spectrophotometer, using chloroform as the blank. Calculate the quantity, in mg, of aspirin (C9H8O4) in the portion of Capsules taken by the formula:C(AU / AS)

in which C is the concentration, in µg per mL, of USP Aspirin RS in the Standard preparation; and AU and AS are the absorbances of the Assay preparation and the Standard preparation, respectively.

Your sample has to be very clean.  Probably the raw material itself since some other molecules absorb at about 280 nm and can interfere.

Calculation  % Acetylsalicyclic Acid in sample:

Absorbance of  sample*wt of std (mg)* Dilution of sample(ml)* % purity of Acetylsalicyclic Acid standard/ Abs of standard* dilution of standard (ml) * wt of sample (mg)

your ans will be same with using two concentration of standard solution

Plot through zero (your system WAS zeroed with a blank, correct?). You should be able to derive a calibration line, since you now have 3 points.

Dear Christina Gabion,Hi,

    If You have two points of absorbance (A) of course, plus the (A) of the unkown, you can use the Bracketing method assuming the calibration of Beer's law is slightly curved.

 You can do that as follows: Asuming You have the Concentrations (C1 and C2 and Absorbances As1 and As2 of your Standards) and for the Unkown (Cx  and Ax).  Write this Equation first  [ As1/C1 = Ax/Cx = As2/C2 ]. Note that, itis Important that both standards points must be very close to the unknown's point of Absorbance. Then make another Equations as follows:  [ (As1- As2)/(C1-C2)] = [(Ax- As2)/(Cx- C2)] ...Here also for easy calculation make the solution concentrations such that As1 of larger value than As2  and Ax larger than As2.   You can see that  ( Cx ) is the only unknown in the equation. I am Sure You can Solve the Equation easily by Yourself.  Thank You and Good Luck.