## 3 Results and Discussion
### Effect of Extraction Temperature  
The TX-114 is a thermo-sensitive polymer, thus, the extraction can be affected by the temperature. It was found that the addition of dyes can raise the cloud point of TX-114, so in order to make sure the phase-separation can be achieved, the effect of temperature in the range of 30-50 \({}^{\circ}\)C for CR and MV and 40-60 \({}^{\circ}\)C for MB was studied, respectively. The results in Figure 7 showed that the extraction efficiency for CR had minor increase with increase of temperature from 30 to 40 \({}^{\circ}\)C, then varied little with further increase of temperature; the extraction efficiency for MB increased with increase of temperature from 40 to 45 \({}^{\circ}\)C, then also varied little with increase of temperature; the extraction efficiency for MV varied little at the temperature range of 30-50 \({}^{\circ}\)C. All these results indicated that the extraction efficiency reached the maximum above a certain temperature then didn't increase with  
Figure 5: Effect of the Triton X-114 (TX-114) concentration on the extraction efficiency of the dyes. (Each system contained 10 mL dyes solution (1 mg/mL CR, MB and 0.125 mg/mL MV), 4 mg Fe3O4@NH2, 40 min vibration time, and incubated at temperature 40 \({}^{\circ}\)C for 10 min). Different letters in the same series indicate significant difference at \(p<0.05\) level.  
Figure 6: Effect of the vibration time on the extraction efficiency of the dyes. (Each system contained 10 mL dyes solution (1 mg/mL CR, MB and 0.125 mg/mL MV), 4 mg Fe3O4@NH2, 4 wt. % TX-114, and incubated at temperature 40 \({}^{\circ}\)C for 10 min). Different letters in the same series indicate significant difference at \(p<0.05\) level.  
further increase of temperature in this study, the similar results were observed in other CPE using non-surfactant as extractant [29; 30]. Thus, the optimal extraction temperature was different for each dye, and the heating wasbeneficial for the extraction.  
Comparison of Magnetic Aqueous Micellar Two-Phase System to Magnetic Solid Phase Extraction and Aqueous Micellar Two-Phase System  
The MAMTPS was combined with the MSPE and AMTPS, thus, it has the advantages of both MSPE and AMTPS. The results of extraction efficiencies for MAMTPS, MSPE and AMTPS, and the phase-separation time for MAMTPS and AMTPS were shown in Figure 8. It can be seen that theMAMTPS had higher extraction efficiency than MSPE and AMTPS. Moreover, MAMTPS had short extraction time than MSPE, the extraction time was 20 min and phase equilibrium time was about 10 min for MAMTPS, which was much shorter than that of 4 h vibration timeforMSPE. The complete phase-separation time of MAMTPS was reduced by \(>\)37% compared with AMTPS at different TX-114 concentration. Similar results were reported that the addition of MNPs can shorten the phase separation time in other ATPSs [18; 31].  
Figure 8: Comparison of the extraction efficiency of CR and phase-separation time of magnetic aqueous micellar two-phase system (MAMTPS) to magnetic solid phase extraction (MSPE) and aqueous micellar two-phase system (AMTPS). (The MAMTPS contained 10 mL CR (1 mg/mL), 4 mg Fe\({}_{3}\)O\({}_{4}\)@NH\({}_{2}\), 4 wt. % TX-114, 40 min vibration time, and incubated at temperature 40\({}^{\circ}\)C for 10 min; the AMTPS contained 10 mL CR (1 mg/mL), 4 wt. % TX-114, 40 min vibration time, and incubated at temperature 40\({}^{\circ}\)C for 10 min, the MSPE contained 10 mL CR (1 mg/mL), 10 mg Fe\({}_{3}\)O\({}_{4}\)@NH\({}_{2}\), 4 h vibration time). The phase-separation time was determined at 3–5 wt. % TX-114 and 30 \({}^{\circ}\)C water bath.  
Figure 7: Effect of the temperature on the extraction efficiency of the dyes. (Each system contained 10 mL dyes solution (1 mg/mL CR, MB and 0.125 mg/mL MV), 4 mg Fe\({}_{3}\)O\({}_{4}\)@NH\({}_{2}\), 4 wt. % TX-114, 20 min vibration time, and incubated at different temperatures for 10 min). Different letters in the same series indicate significant difference at \(p<0.05\) level.