| 1 potassium ferrioxalate-amikacin systemsIn a weak acid medium, potassium ferrioxalate can react with some aminoglycoside antibiotics, such as amikacin (AMK), kanamycin (KANA), tobramycin (TOB) and gentamicin (GEN) to form ion-association complexes. It results in the enhancement of resonance Rayleigh scattering (RRS) in different degrees. And the maximum scattering peaks are all located at 345 nm. Among them the relative scattering intensity (△IRRS) of AMK system is much higher than that of KANA, TOB and GEN. Therefore the method is more propitious to the determination of trace amounts of AMK. The optimum reaction conditions, influencing factors, and the relationship between scattering intensities and concentration of antibiotics have been discussed by the proposed method. It is seen that the enhancement of RRS signals is directly proportional to the concentration of antibiotics in the range of 0.006-3.0μg/mL. A new resonance Rayleigh scattering method for the determination of AMK and other aminoglycoside antibiotics with [Fe(C2O4)3]3- as a probe is established based on it. The method exhibits high sensitivity. The detection limit (3σ) for AMK is 1.8 ng/mL. The method has good selectivity and can be applied to the determination of AMK in clinical urine samples. The reaction mechanism and the reasons for RRS enhancement have been discussed in this paper.2 isopoly tungstic acid-amikacin systemsA new rapid and sensitive resonance Rayleigh scattering (RRS) method for the determination of amikacin (AMK) has been established. In pH 0.65-1.10 HCl-NaAc buffer solution, isopoly tungstic acid (IPT) can react with AMK to form an ion-association complex, which will result in great enhancement of RRS and the appearance of a new RRS spectrum. The maximum scattering peak is located at 340 nm. The scattering intensity is proportional to the concentration of AMK in the range of 0.001-0.08μg/mL. The detection limit (3σ) is 0.4 ng/mL. Based on it, a new resonance Rayleigh scattering (RRS) method has been developed for the quick and sensitive determination of amikacin (AMK). The RRS characteristics, absorption spectrum characteristics and optimum reaction conditions of the system are discussed. Effects of coexistent substances are tested. The method exhibits high sensitivity. It is suitable for the determination of AMK in human serum and urine samples.3 potassium ferrioxalate-chlorpromazine or promethazine systemsThe interactions of phenothiazine, such as, chlorpromazine hydrochloride (CPZ) and promethazine hydrochloride (PZ) with potassium ferrioxalate (PF) have been investigated by a resonance Rayleigh scattering (RRS) technique. Both CPZ and PZ can react with PF to form ion-association complexes, which can result in the significant enhancement of RRS intensity. The maximum scattering peaks exist at 368 nm for CPZ-PF and 370 nm for PZ-PF. Job's method and the molar ratio method showed that the ratio of PF to CPZ or PZ is 1:3. The RRS spectral characteristics, the optimum conditions of reactions, and influencing factors have been studied for CPZ-PF and PZ-PF reaction systems. There is a linear relationship between the RRS intensity and the drug concentration in the range of 0.02-8.00μg mL-1 for CPZ and 0.04-9.00μg mL-1 for PZ. This is the first report of potassium ferrioxalate as a probe of RRS to determine CPZ and PZ at nanogram levels, and the detection limits (3σ) are 6.6 ng mL-1 for CPZ and 10.6 ng mL-1 for PZ. It shows the method has high sensitivity, good selectivity, and strong stability. The proposed method has been applied to determine CPZ in urine samples with satisfactory results. Moreover, the reaction mechanism and the reasons for intensity enhancement of RRS have been discussed.4 atracurium fluorescence systemsBased on the characteristic that atracurium has strong fluorescence itself, a fluorescence spectrophotometry method for the simple, rapid and direct determination of atracurium has been developed. The excitation wavelength of atracurium is located at 280 nm. The emission wavelength of atracurium is located at 317 nm. The intensity of fluorescence signals is directly proportional to the concentration of atracurium in the range of 0.088-7.5μg/mL. The detection limit (3σ) is 26.5 ng/mL. The spectra characteristics, the optimum reaction conditions and influencing factors have been discussed by the proposed method. The method has a good selectivity. It has been applied to the determination of atracurium in human serum samples, urine samples and synthetic samples with satisfying results.5 multi-halofluorescein-atracurium systems In weak acid buffer solutions, 6 multi-halofluorescein dyes, such as ethyl eosin (EE), erythrosine (TIF), phloxine (PX), eosin Y (EY), eosin B (EB) and rose bengal (RB), can react with atracurium to form ion-association complexes, which not only results in the quenching of fluorescence (except rose bengal), but also results in the great enhancement of resonance Rayleigh scattering (RRS). Furthermore, a new RRS spectrum will appear. In this work, the spectral characteristics of fluorescence and RRS, the optimum conditions of the reaction, influencing factors and effects of coexistent substances were investigated. A new method for the determination of atracurium by using a multi-halofluorescein as a probe has been developed. There was a linear relationship between the fluorescence and RRS intensities and the drug concentration for EE-AB system in the range of 0.061-1.25 (λex/λem=299/545), 0.007-1.6 (λex/λem=559/559) and 0.023-1.6μg/mL (λex/λem=322/322), respectively. The detection limit for AB was 18.3 ng/mL (λex/λem=299/545) for fluorophotometry, 2.1 (λex/λem=559/559) and 6.8 (λex/λem=322/322) ng/mL for RRS method. For TIF-AB system, the linear range was 0.159-2.0 (λex/λem=309/555), 0.021-1.5 (λex/λem=567/567) and 0.028-1.5 (λex/λem=291/291)μg/mL, respectively. The detection limit was 47.6 (λex/λem=309/555), 6.3 (λex/λem=567/567) and 8.3 (λex/λem=291/291) ng/mL, respectively. For PX-AB system, the linear range was 0.126-1.0 (λex/λem=301/560), 0.092-1.8 (λex/λem=580/580) and 0.051-1.8 (λex/λem=332/332)μg/mL, respectively. The detection limit was 37.7 (λex/λem=301/560), 27.7 (λex/λem=580/580) and 15.3 (λex/λem=332/332) ng/mL, respectively. For EY-AB system, the linear range was 0.096-1.5 (λex/λem=299/544), 0.010-1.8 (λex/λem=563/563) and 0.014-1.8 (λex/λem=309/309)μg/mL, respectively. The detection limit was 28.9 (λex/λem=299/544), 3.0 (λex/λem=563/563) and 4.2 (λex/λem=309/309) ng/mL, respectively. For EB-AB system, the linear range was 0.141-2.0 (λex/λem=301/543), 0.113-1.6 (λex/λem=566/566) and 0.083-1.6 (λex/λem=359/359) ug/mL, respectively. The detection limit was 42.3 (λex/λem=301/543), 33.9 (λex/λem=566/566) and 24.9 (λex/λem=359/359) ng/mL, respectively. For RB-AB system, the linear range was 0.135-2.0 (λex/λem=566/566) and 0.031-2.0 (λex/λem=310/310)μg/mL, respectively. The detection limit was 40.5 (λex/λem=566/566) and 9.2 (λex/λem=310/310) ng/mL, respectively. The reasons for the enhancement of scattering spectra were discussed.6 dihalofluorescein-atracurium systemsIn weak acid buffer solutions, 3 dihalofluorescein dyes, such as diiodofluorescein, dibromofluorescein and dichlorofluorescein, can react with atracurium to form ion-association complexes, which not only results in the quenching of fluorescence, but also results in the great enhancement of resonance Rayleigh scattering (RRS). Furthermore, a new RRS spectrum will appear. In this work, the spectral characteristics of fluorescence and RRS, the optimum conditions of the reaction, influencing factors and effects of coexistent substances were investigated. A new method for the determination of atracurium by using a dihalofluorescein as a probe has been developed. There was a linear relationship between the fluorescence and RRS intensities and the drug concentration for AB-I2-F system in the range of 0.259-1.875 (λex/λem=300/543)μg/mL, 0.051-1.25 (λex/λem=559/559) and 0.087-1.25 (λex/λem=309/309)μg/mL, for AB-Br2-F system in the range of 0.066-2.5μg/mL (λex/λem=293/534), 0.053-1.0 (λex/λem=548/548) and 0.018-1.0 (λex/λem=309/309)μg/mL, and for AB-Cl2-F system in the range of 0.032-2.5μg/mL (λex/λem=288/530), 0.226-1.5 (λex/λem=559/559) and 0.030-1.5 (λex/λem=309/309)μg/mL. For AB-I2-F system, the detection limits for AB was 77.6 ng/mL (λex/λem=300/543) for fluorophotometry, 15.3 (λex/λem=559/559) and 26.1 (λex/λem=309/309) ng/mL for RRS method. For AB-Br2-F system, the detection limits for AB was 19.7 ng/mL (λex/λem=293/534) for fluorophotometry, 15.8 (λex/λem=548/548) and 5.4 (λex/λem=309/309) ng/mL for RRS method. For AB-Cl2-F system, the detection limits for AB was 9.7 ng/mL (λex/λem=288/530) for fluorophotometry, 67.7 (λex/λem=559/559) and 9.0 (λex/λem=309/309) ng/mL for RRS method. The reasons for the enhancement of scattering spectra were discussed.7 erythrosine-amikacin systemsIn acid medium, amikacin (AMK) reacts with erythrosine (TIF) to form an ion-association complex, which makes the dye fade. The maximum fading wavelength is located at 527 nm. The maximum molar absorptivityεis 1.46×105 L·mol-1·cm-1. Beer's law is obeyed in the concentration range 0.064-2.5μg/mL. The spectra characteristics, optimum reaction conditions and the influence of foreign substances have been investigated. The method has good selectivity. The method has been applied for determination of the amikacin in human serum samples and urine samples with satisfactory results.
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