Determination Of Fluoroquinolones By Mixed Micelle-Cloud Point Extraction Fluorescence Spectrophotometry

Objective:To establish an economical,environmentally friendly,sensitive and convenient mixed micelle-cloud point extraction fluorescence spectrophotometry for determination of levofloxacin,gatifloxacin,marbofloxacin and moxifloxacin in environmental water samples and pharmaceutical preparations.Methods:Levofloxacin,gatifloxacin,marbofloxacin and moxifloxacin in environmental water samples and drug preparations were separated and enriched by mixed micelle-cloud point extraction,and then detected and analysed by fluorescence spectrophotometer.The different parameters affecting the cloud point extraction of the four drugs were investigated,and the optimum conditions were determined.Results:（1）Optimal cloud point extraction conditions for levofloxacin:System pH=1.5,the concentrations of SDS,TX-114 and NaCl solution were 0.40%,0.15%,and 6.00%respectively,the equilibrium temperature was 25℃and equilibrium time was 5 min,the excitation wavelength and emission wavelength were 296 nm and 495 nm,respectively.Under the optimum conditions,the concentrations of levofloxacin in environmental water samples and pharmaceutical preparations showed a good linear relationship with fluorescence intensity in the range of 5.00²50.00 ng·mL^-1.The correlation coefficient was r=0.9996.The limit of detection and the limit of quantification was 0.17 ng·mL^-11 and 0.50ng·mL^-1,respectively.The RSD values were 1.78%and 0.39%,respectively.The recovery results of spiked samples were 96.07%¹06.60%and 100.65%¹02.30%,respectively.There were no significant differences between the proposed method and the method reported in literature and pharmacopoeia for determining the content of levofloxacin in environmental water samples and injections.（2）Optimal cloud point extraction conditions for gatifloxacin:System pH=2.0,the concentrations of SDS,TX-114 and NaCl solution were 0.50%,0.15%,and 6.00%respectively,the equilibrium temperature was 25℃and equilibrium time was 10 min,the excitation wavelength and emission wavelength were 295 nm and 480 nm,respectively.Under the optimum conditions,the concentrations of gatifloxacin in environmental water samples and pharmaceutical preparations showed a good linear relationship with fluorescence intensity in the range of 4.00⁵00.00 ng·mL^-1.The correlation coefficient was r=0.9991.The limit of detection and the limit of quantification was 0.27 ng·mL^-11 and 0.81ng·mL^-1,respectively.The RSD values were 0.85%and 1.39%,respectively.The recovery results of spiked samples were 95.35%¹06.00%and 97.63%¹01.46%,respectively.There were no significant difference between the proposed method and the method reported in literature for determining the content of gatifloxacin in environmental water samples and capsules.（3）Optimal cloud point extraction conditions for marbofloxacin:System pH=3.0,the concentrations of SDS,TX-114 and NaCl solution were 0.50%,0.15%,and 6.00%respectively,the equilibrium temperature was 25℃and equilibrium time was 15 min,the excitation wavelength and emission wavelength were 298 nm and 510 nm,respectively.Under the optimum conditions,the concentrations of marbofloxacin in environmental water samples and pharmaceutical preparations showed a good linear relationship with fluorescence intensity in the range of 5.00¹000.00 ng·mL^-1.The correlation coefficient was r=0.9996.The limit of detection and the limit of quantification was 0.33 ng·mL^-11 and1.00 ng·mL^-1,respectively.The RSD values were 1.36%and 0.62%,respectively.The recovery results of spiked samples were 96.10%¹05.35%and 98.09%¹01.73%,respectively.There were no significant difference between the proposed method and the method reported in literature for determining the content of marbofloxacin in environmental water samples and tables.（4）Optimal cloud point extraction conditions for moxifloxacin:System pH=3.5,the concentrations of SDS,TX-114 and NaCl solution were 0.30%,0.15%,and 6.00%respectively,the equilibrium temperature was 25℃and equilibrium time was 15 min,the excitation wavelength and emission wavelength were 294 nm and 500 nm,respectively.Under the optimum conditions,the concentrations of moxifloxacin in environmental water samples and pharmaceutical preparations showed a good linear relationship with fluorescence intensity in the range of 5.00³00.00 ng·mL^-1.The correlation coefficient was r=0.9991.The limit of detection and the limit of quantification was 0.09 ng·mL^-11 and 0.26ng·mL^-1,respectively.The RSD values were 1.97%and 0.82%,respectively.The recovery results of spiked samples were 92.64%¹06.17%and 95.06%¹01.82%,respectively.There were no significant difference between the proposed method and the method reported in literature for determining the content of moxifloxacin in environmental water samples and tables.Conclusion:The proposed mixed micelle-cloud point extraction fluorescence spectrophotometry is an accurate,economical,sensitive,environmentally friendly and easy to be promoted method.The proposed method cloud be applied to determine the contents of levofloxacin,gatifloxacin,marbofloxacin and moxifloxacin in actual environmental water samples and pharmaceutical preparations.