Quantitative Analysis of Bromoxynil and MCPA

RP-HPLC–UV system used was from Shimadzu Japan LC-20AT with SPD-20A detector where detector wavelength used was 230 nm and Column C18 Zorbax Agilent Technologies serial number 560562 (250 × 4.6 mm (i.d) × 5 µm). The mobile phase used was (Methanol 90% + Water 10%). The flow rate was maintained at 1.5 mL/min and the approximate retention time was observed to be 5.79 min for Bromoxynil and 6.797 min for MCPA pure active contents [42 (link)].
The Bromoxynil + MCPA contents were quantitatively determined by the use of pure external analytical standards of Bromoxynil and MCPA purchased from Chem Services USA and FLUKA Sigma Aldrich Germany respectively and by use of correction factor using the following Eq. 1 [41 ]. $$\text{Bromoxynil Octanoate contents \%}\left(\frac{\text{w}}{\text{w}}\right)\text{X}1={\text{A}}_2{\text{x m}}_1\text{x P}/{\text{A}}_1{\text{x m}}_2$$
Bromoxynil Octanoate Contents % (w/w) × 0.6873 (Factor to convert Bromoxynil Octanoate to Bromoxynil).
Bromoxynil Contents % (w/v) = Bromoxynil% (w/w) x Density of Bromoxynil Liquid sample of mixture (CUTOUT 40% W/V).
Where:
A₁ = Average peak area of the Bromoxynil in the standard solution.
A₂ = Average peak area of the Bromoxynil in the sample solution.
m₁ = mass of Bromoxynil standard (mg).
m₂ = mass of Bromoxynil sample (mg).
P = Purity of Bromoxynil analytical standard.
Similarly, the contents of MCPA% (w/v) can also be calculated from above equation used for calculating Bromoxynil active ingredient contents% (w/v).
While the factor used for the conversion of MCPA -2- Ethylhexyl to MCPA is 0.6413.