test 1, limit of butyl methacrylate and methyl methacrylate
pH 2.0 Phosphate buffer (0.0625 M)
Prepare an aqueous solution containing 8.9 g of anhydrous dibasic sodium phosphate and 8.5 g of monobasic potassium phosphate per L. Adjust with phosphoric acid to a pH of 2.0.
Mobile phase
Prepare a mixture of methanol and pH 2.0 Phosphate buffer (0.0625 M) (55:45).
Standard solution
Prepare a solution in acetonitrile having a concentration of about 1000 µg per mL each of butyl methacrylate and methyl methacrylate. Dilute 1.0 mL of the solution to 250.0 mL with water, and mix.
Test solution
Dissolve about 1.0 g of Amino Methacrylate Copolymer, accurately weighed, in pH 2.0 Phosphate buffer (0.0625 M), and dilute with pH 2.0 Phosphate buffer (0.0625 M) to 50.0 mL, and mix.
Chromatographic system (see Chromatography
621
)
The liquid chromatograph is equipped with a 205-nm detector and a 4.6-mm × 12-cm column that contains packing L1. The flow rate is about 2 mL per minute. Chromatograph the
Standard solution, and record the peak responses as directed for
Procedure: the resolution,
R, between butyl methacrylate and methyl methacrylate is not less than 10; and the relative standard deviation for replicate injections is not more than 3.0%.
Procedure
Separately inject equal volumes (about 50 µL) of the
Standard solution and the
Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in µg, of each monomer in the portion of Amino Methacrylate Copolymer taken by the formula:
50C(rU / rS)
in which
C is the concentration, in µg per mL, of each monomer in the
Standard solution; and
rU and
rS are the peak responses of each monomer obtained from the
Test solution and the
Standard solution, respectively: not more than 0.1% of each monomer is found.
test 2, limit of 2-dimethylaminoethyl methacrylate
Monobasic potassium phosphate solution (0.025M)
Prepare an aqueous solution containing 3.4 g of monobasic potassium phosphate per L.
Mobile phase
Prepare a mixture of Monobasic potassium phosphate solution (0.025M) and tetrahydrofuran (75:25).
Standard solution
Prepare a solution in tetrahydrofuran having a concentration of about 200 µg per mL of (2-dimethylaminoethyl) methacrylate. Dilute 2.0 mL of the solution to 50.0 mL with tetrahydrofuran, and mix.
Test solution
Dissolve about 1.0 g of Amino Methacrylate Copolymer, accurately weighed, in tetrahydrofuran, dilute with tetrahydrofuran to 50.0 mL, and mix.
Chromatographic system (see Chromatography
621
)
The liquid chromatograph is equipped with a 215-nm detector and a 4.6-mm × 12-cm column that contains packing L8. The flow rate is about 2 mL per minute. Chromatograph the
Standard solution, and record the peak responses as directed for
Procedure: the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 50 µL) of the
Standard solution and the
Test solution into the chromatograph, record the chromatograms, and measure the response for the major peak. Calculate the quantity, in µg, of (2-dimethylaminoethyl) methacrylate in the portion of Amino Methacrylate Copolymer taken by the formula:
50C(rU / rS)
in which
C is the concentration, in µg per mL, of the monomer in the
Standard solution; and
rU and
rS are the peak responses of (2-dimethylaminoethyl) methacrylate obtained from the
Test solution and the
Standard solution, respectively: not more than 0.1% is found.