## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{2}{*}{**Compound**} & \multirow{2}{*}{
\begin{tabular}{c} **Conc.** \\ **(\#g/mL)** \\ \end{tabular} } & \multicolumn{2}{c}{**Recovery**} & \multicolumn{2}{c}{**Intra-Day**} & \multicolumn{2}{c}{**Inter-Day**} \\ \cline{3-8}  & **(\#g/mL)** & **Mean (\%)** & **RSD (\%)** & **Accuracy (\%)** & **Precision** (RSD\%)** & **Accuracy (\%)** & **Precision** (RSD\%)** \\ \hline Basic Blue 26 & 0.24 & 100.90 & 1.26 & 98.67 & 2.06 & 100.96 & 2.61 \\  & 2.40 & 101.05 & 0.67 & 99.89 & 1.06 & 99.89 & 0.64 \\  & 12.00 & 103.03 & 0.96 & 99.45 & 0.84 & 98.67 & 0.71 \\ \hline Basic Red 2 & 0.90 & 99.48 & 2.30 & 100.87 & 1.41 & 101.24 & 0.48 \\  & 9.00 & 100.01 & 0.75 & 99.85 & 0.89 & 99.96 & 0.55 \\  & 45.00 & 101.61 & 0.82 & 99.46 & 0.80 & 98.74 & 0.64 \\ \hline Basic Yellow 28 & 0.60 & 100.39 & 1.44 & 100.75 & 2.16 & 102.41 & 1.96 \\  & 6.00 & 98.09 & 0.94 & 99.98 & 0.89 & 99.87 & 0.63 \\  & 30.00 & 98.98 & 0.94 & 99.58 & 0.91 & 99.12 & 0.45 \\ \hline Disperse Brown 1 & 0.04 & 102.29 & 7.36 & 104.96 & 7.72 & 100.24 & 6.44 \\  & 0.40 & 106.48 & 3.60 & 101.34 & 1.32 & 100.95 & 1.22 \\  & 2.00 & 102.68 & 0.71 & 101.48 & 0.19 & 100.27 & 1.25 \\ \hline Disperse Orange 3 & 0.04 & 105.33 & 9.63 & 98.38 & 3.40 & 101.74 & 4.56 \\  & 0.40 & 104.17 & 0.73 & 101.24 & 0.61 & 100.39 & 1.28 \\  & 2.00 & 102.51 & 0.44 & 101.87 & 0.22 & 100.64 & 1.11 \\ \hline Disperse Yellow 3 & 0.16 & 104.80 & 5.06 & 89.74 & 4.54 & 92.09 & 2.95 \\  & 1.60 & 101.68 & 1.05 & 102.36 & 0.25 & 100.65 & 1.59 \\  & 8.00 & 101.72 & 0.89 & 102.35 & 0.19 & 100.60 & 1.61 \\ \hline HC Blue No. 2 & 0.11 & 96.30 & 1.99 & 92.25 & 6.56 & 96.61 & 4.95 \\  & 1.10 & 101.11 & 1.54 & 102.75 & 0.53 & 104.02 & 4.01 \\  & 5.50 & 100.48 & 1.10 & 102.69 & 0.51 & 103.66 & 5.25 \\ \hline HC Yellow No. 5 & 0.03 & 99.53 & 6.26 & 91.68 & 9.06 & 90.80 & 9.19 \\  & 0.30 & 103.79 & 1.83 & 104.95 & 1.15 & 103.73 & 1.98 \\  & 1.50 & 103.97 & 1.21 & 102.64 & 0.32 & 100.74 & 1.71 \\ \hline Solvent Orange 4 & 0.02 & 99.27 & 9.24 & 81.20 & 7.02 & 86.34 & 6.07 \\  & 0.20 & 97.57 & 2.09 & 102.54 & 0.69 & 102.15 & 0.73 \\  & 1.00 & 97.31 & 0.91 & 103.77 & 1.40 & 101.82 & 1.73 \\ \hline Solvent Orange 7 & 0.30 & 98.58 & 8.11 & 107.44 & 3.80 & 102.44 & 9.80 \\  & 3.00 & 95.99 & 1.54 & 101.35 & 2.94 & 100.58 & 0.68 \\  & 15.00 & 97.25 & 0.49 & 101.89 & 0.68 & 100.72 & 1.07 \\ \hline \end{tabular}
\end{table} 
Table 4: Recovery, accuracy, and precision of colorants in hair tint sample with different concentrations using HPLC-DAD. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Compound**} & \multirow{2}{*}{
\begin{tabular}{c} **Conc.** \\ **(\#g/mL)** \\ \end{tabular} } & \multicolumn{2}{c}{**Recovery**} & \multicolumn{2}{c}{**Intra-Day**} & \multicolumn{2}{c}{**Inter-Day**} \\ \cline{3-8}  & **Mean (\%)** & **RSD (\%)** & **Accuracy (\%)** & **Precision** (RSD\%)** & **Accuracy (\%)** & **Precision** (RSD\%)** \\ \hline Solvent Red 24 & 3.00 & 101.10 & 1.55 & 88.85 & 5.29 & 86.80 & 6.62 \\  & 30.00 & 100.71 & 1.34 & 101.78 & 0.57 & 100.21 & 1.36 \\  & 150.00 & 101.11 & 0.32 & 99.69 & 0.14 & 100.30 & 0.96 \\ \hline Solvent Yellow 1 & 0.60 & 97.69 & 1.22 & 89.49 & 7.55 & 90.41 & 2.12 \\  & 6.00 & 98.23 & 1.02 & 100.80 & 0.93 & 100.48 & 0.29 \\  & 30.00 & 99.43 & 0.53 & 99.40 & 0.47 & 100.37 & 0.91 \\ \hline Solvent Yellow 3 & 0.90 & 99.01 & 1.17 & 88.93 & 8.05 & 90.38 & 2.07 \\  & 9.00 & 99.47 & 1.02 & 100.70 & 0.92 & 100.44 & 0.22 \\  & 45.00 & 100.26 & 0.44 & 99.50 & 0.48 & 100.37 & 0.80 \\ \hline \end{tabular}
\end{table} 
Table 3: _Cont._In addition, to check the illegal colorant ions, multiple reaction monitoring (MRM) conditions for each compound were confirmed using LC-MS/MS. Each standard solution was directly infused to find the precursor ion. Then, the product ion was obtained by adjusting the collision energy. Two or more transitions were selected for each analyte. The optimized MRM transitions are listed in Table 5. Disperse Yellow 3 and HC Yellow No.