Resonance Rayleigh scattering measurement of aminoglycoside antibiotics with Evans Blue.

In a weak acid medium, some aminoglycoside antibiotics, such as kanamycin (KANA), gentamicin (GEN), tobramycin (TOB) and neomycin (NEO), or acid bisazo dye Evans Blue (EB) can only produce very weak resonance Rayleigh scattering (RRS) signals. However, when two agents react with each other to form ion-association complexes, the RRS intensity can be greatly enhanced and a new RRS spectrum with a significant enhancement of the RRS intensity in the wavelength range from 350 nm to 600 nm can be observed. The maximum scattering peak is at 570 nm. There is a linear relationship between the RRS intensity and the antibiotic concentration in the range of 0.01-6.0 microg mL(-1) at 570 nm. This RRS method for the determination of aminoglycoside antibiotics at trace-amount levels has been developed. The detection limits (3sigma) of the four antibiotics, whose order of sensitivity from high to low ranks as KANA > NEO > TOB > GEN, are 5.2-6.9 ng mL(-1). This method has good selectivity and has been successfully applied to the quick determination of antibiotics not only for injections and ear drops, but for clinic serum samples as well. In addition, the reaction mechanism by using a quantum chemistry method and the influencing factors of the RRS spectra and the enhancement reasons of RRS have been discussed.     

Resonance Rayleigh-scattering method for the determination of sildenafil citrate in a pharmaceutical formulation using Evans blue.

A highly sensitive resonance Rayleigh-scattering (RRS) method for the determination of sildenafil citrate has been developed, based on the fact that sildenafil (Sild) reacted with Evans Blue (EB) to form an ion-association complex in pH 1.1 - 4.6 aqueous solution. This resulted in a significant enhancement of the RRS intensity, and a new spectrum appeared. The wavelength of the maximum RRS was at 365 nm, and other scattering peaks were at 400, 442, 470 and 534 nm, respectively. The intensity of RRS was directly proportional to the concentration of Sild in the range 0 - 11.5 microg ml(-1), and the detection limit for Sild (3 sigma) was 30.3 ng ml(-1). The composition of the ion-association complex was Sild:EB = 1:1, as established by Job's method. The method had good selectivity and could be applied to the determination of Sild in the aqueous phase without using organic solvent extraction. The method was simple and rapid. In addition, the reaction mechanism and the reason for RRS enhancement were considered.     

Resonance Rayleigh scattering spectra for studying the interaction of aminoglycoside antibiotics with pontamine sky blue and their analytical applications

In a weakly acid medium, some aminoglycoside antibiotics, such as kanamycin (KANA), gentamicin (GEN), tobramycin (TOB), and neomycin (NEO), or acid bisazo dye pontamine sky blue (PSB) can only produce very weak resonance Rayleigh scattering (RRS) signals. However, when the two agents react with each other to form the ion association complexes, the RRS intensity can be enhanced greatly and a new RRS spectrum and a significant enhancement of the RRS intensity in the wavelength range 350-600 nm can be observed. The maximum scattering peak is at 580 nm. There is a linear relationship between the RRS intensity and the antibiotic concentration in the range 0.01-6.0 microg mL(-1) at 580 nm. This RRS method has therefore been developed for the determination of trace levels of aminoglycoside antibiotics. The detection limits (3 sigma) of the four antibiotics, whose order of sensitivity is KANA>NEO>TOB>GEN, are 5.8-6.9 ng mL(-1). This method has a good selectivity and has been successfully applied to the quick determination of antibiotics not only for injections and ear drops, but clinic serum samples as well. In addition, quantum chemistry-based analysis of the reaction mechanism, the factors influencing the RRS spectra, and the reasons for the enhancement of RRS are discussed.     

Study on the resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectra of the interactions of palladium(II)-ceftriaxone chelate with anionic surfactants and their analytical applications

In pH 1.8-2.9 Britton-Robinson (BR) buffer medium, ceftriaxone (CTRX) can react with palladium(II) (Pd(II)) to form 1:2 cationic chelate, which can further react with anionic surfactants (AS) such as sodium lauryl sulfonate (SLS), sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) to form 1:3 ion-association complexes. As a result, the resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS) were enhanced greatly. The maximum RRS, SOS and FDS wavelengths of three ion-association complexes were located at 335 nm, 560 nm and 390 nm, respectively. The increments of scattering intensity (DeltaI) were directly proportional to the concentrations of CTRX in certain ranges. The detection limits (3sigma) of CTRX for SLS, SDBS and SDS systems were 1.8 ng ml(-1), 2.3 ng ml(-1) and 2.3 ng ml(-1) (RRS method), 4.9 ng ml(-1), 7.4 ng ml(-1) and 4.7 ng ml(-1) (SOS method) and 6.8 ng ml(-1), 7.3 ng ml(-1) and 9.1 ng ml(-1) (FDS method), separately. The sensitivity of RRS method was higher than those of SOS and FDS methods. The optimum conditions of RRS method and the influence factors were investigated, and the composition of ion-association complexes and the reaction mechanism were discussed also. The effects of foreign substances were tested and it showed that the method has a good selectivity. Based on the ion-association reaction, the sensitive, simple and rapid methods for the determination of CTRX have been developed.     

Determination of vitamin B12 in multivitamin tablets and fermentation medium by high-performance liquid chromatography with fluorescence detection

A novel method for the determination of vitamin B12 by high-performance liquid chromatography with fluorescence detection is reported. The method was simple and highly sensitive with good precision. Vitamin B12 was analyzed by HPLC on a muBondapak C18 column (300x3.9 mm, 10 microm) with methanol-water (30:70) as mobile phase and fluorescence detection at 305 nm (with excitation at 275 nm). The calibration graph was linear from 1.000 to 100.0 ng ml(-1) for vitamin B12 with a correlation coefficient of 0.998 (n=6). The detection limit was 0.1 ng ml(-1). The method was successfully applied to the determination of vitamin B12 in vitamin B12 tablets, multivitamin tablets and fermentation medium. The recovery was from 94 to 102% and the relative standard deviation was in the range of 1.8 to 4.1%.     

Resonance Rayleigh scattering spectrum for the chelate of lanthanum(Ⅲ) with sodium tanshinon ⅡA silate and its analytical application

In a pH 3.6-5.0 Hac-NaAc buffer solution, when sodium tanshinon ⅡA silate (STSⅡA) reacts with La(Ⅲ) to form a chelate, the resonance Rayleigh scattering (RRS) intensity can be enhanced greatly and a new RRS spectrum will appear. The maximum RRS peak is located at 306 nm and the RRS intensity is proportional to the concentration of STSⅡA in a certain range. The method is very sensitive and the detection limit for STSⅡA (3σ/K) is 82.12 ng·mL-1. The optimum reaction conditions and the effect of coexisting substances have been investigated. A new, simple and fast method for the determination of STSⅡA based on RRS method is developed. It can be applied to the determination of STSⅡA in the synthesis samples and Nuoxinkang injection. Combined with infrared absorption and NMR spectra, the structure of the chelate and the reasons of RRS enhancement are also discussed.     

曲利本红与氨基糖苷类抗生素相互作用的共振瑞利散射光谱及其分析应用

在弱酸条件下，酸性双偶氮染料曲利本红（TR）或硫酸卡那霉（KANA）、硫酸 新霉素（NEO）、硫酸庆大霉素（GEN）和硫酸妥布霉素（TOB）等氨基糖苷类抗生 素的各自共振瑞利散射（RRS）十分微弱，但两者相互作用形成离子缔合物时能使 RRS急剧提高并产生新的RRS光谱，在400～535nm之间有一个强的散射带，最大散射 峰位于400nm处，在0.013～6.0μg·mL~(-1)范围内RRS强度与抗生素浓度成正比， 可用于氨基糖苷类抗生素的测定，对不同抗生素的检出限（3σ）在12.9～17.6ng ·mL~(-1)之间，其灵敏度的顺序是KANA＞NEO＞TOB＞GEN,方法有较好的选择性， 可用于市售抗生素注射液或滴耳液中药物含量和临床血药浓度的快速测定，中还用 量子化学方法对反应机理进行探讨，并讨论了的RRS光谱特性的影响因素和RRS增强 的原因。     

维生素B12与12-钨磷酸相互作用的双波长共振瑞利散射光谱及其分析应用

建立了一种双波长共振瑞利散射光谱测定维生素B12的新方法. 在pH=1.0的HCl介质中, 维生素B12(VB12)与12-钨磷酸(TP)形成摩尔比为3:1的离子缔合物, 导致双波长共振瑞利散射(DWO-RRS)、 二级散射(SOS)和倍频散射(FDS)光谱显著增强, 其最大散射波长分别位于330和370 nm(RRS), 608 nm(SOS)和386 nm(FDS). 在一定范围内, 3种散射增强(ΔIRRS, ΔISOS和ΔIFDS)均与VB12的浓度成线性关系. 该方法具有较高的灵敏度, RRS, SOS和FDS法对VB12的检出限(3σ)在2.0~7.6 ng/mL之间. 研究了反应条件和共存物质的影响, 结果表明, 该方法具有良好的选择性. 据此, 提出了简便、 快速、 准确且高灵敏测定痕量VB12的光散射新方法, 适用于片剂和尿样中VB12的测定. 还对反应机理和散射光谱增强的原因进行了讨论.     

金纳米微粒作探针共振瑞利散射光谱法测定盐酸异丙嗪

在pH 1.8～3.0的酸性介质中,质子化的盐酸异丙嗪(PMZ)可与带负电荷的金纳米微粒依靠静电和疏水作用相互结合,导致共振瑞利散射(RRS)强度显著增强,其最大散射峰位于368 nm,并在284,440,498 nm处有明显的散射峰,在选定的测量波长下,盐酸异丙嗪在0.04～0.10μg/mL的浓度范围内与RRS强度成正比,该法具有高的灵敏度,其检出限为1.34 ng/mL。考察了体系的RRS光谱特征,研究了适宜的反应条件、影响因素,研究了共存物质的影响,据此建立了金纳米微粒作探针RRS法测定盐酸异丙嗪的新方法。     

氯金酸-小檗碱离子缔合物体系的共振瑞利散射光谱研究及其分析应用

在pH＝2.0的HCl-NaOAc缓冲溶液中, 小檗碱阳离子与氯金酸根阴离子由于静电引力和疏水作用力形成离子缔合物时, 将引起溶液共振瑞利散射(RRS)显著增强, 并产生新的RRS光谱, 其最大RRS波长位于370 nm, 另在277 nm也有一个较强的RRS峰. 在1.83×10^－8～5.0×10^－6 mol/L范围内小檗碱浓度与散射强度(ΔI)成正比; 反应有很高的灵敏度, 对小檗碱的检出限(3σ/K)为1.83×10^－8 mol/L (7.5 ng/mL). 研究了共振瑞利散射光谱测定小檗碱的影响因素, 考察了共存物质的影响, 实验表明该方法有良好的选择性. 基于小檗碱与氯金酸反应产物的RRS光谱, 发展了一种高灵敏、简便、快速测定小檗碱的新方法, 用于中成药和中药饮片样品的测定, 结果满意. 本文还对反应机理进行了初步的探讨.     

利福霉素类抗生素-Cu(II)-核酸体系的RRS光谱研究

在Britton-Robinson (B-R)缓冲溶液中, 利福霉素类药物与ctDNA反应的适宜的pH范围是1.9～2.1. 此类药物本身有微弱RRS峰, 它们具有相似的光谱特征, 其散射峰均在290和370 nm附近; 而ctDNA的RRS峰在310 nm处. 两者反应形成结合产物后其RRS明显增强, 并在375 nm左右出现最大散射峰, 且有不同程度的红移和散射增强, 说明两者结合成新的产物; 加入Cu2＋离子后, Cu2＋与利福霉素抗生素及DNA形成三元复合物, 此时将导致RRS进一步剧增, 而且RRS光谱增强值与DNA浓度呈正比, 因而可用于DNA测定具有较高的灵敏度, 实验对ctDNA的检出限为9.7 ng/mL (RFSV-Cu2＋- ctDNA体系). 文中研究了三元配合物反应的适宜条件和影响因素, 基于此反应发展了一种用RRS技术测定DNA的新方法.     

钯(II)-柠檬黄-离子液体三元络合体系的共振瑞利散射光谱及其分析应用研究

在pH 2.0～6.0的BR缓冲溶液中, Pd(II)与柠檬黄(TTZ)形成的络离子与溴化1-十六烷基-3-甲基咪唑([C₁₆mim]Br)离子液体发生作用形成离子缔合物, 引起溶液共振瑞利散射(RRS)显著增强, 并产生新的RRS光谱, 其最大RRS峰位于458 nm. 在0.043～0.860 μg/mL范围内散射强度(ΔI)与柠檬黄的浓度成正比. 该方法简单灵敏, 对柠檬黄的检出限(3σ/K)为5.5 ng/mL (n＝11). 建立了一种简便、快速测定柠檬黄的新方法, 并成功用于饮料样中柠檬黄含量的测定.     

Resonance Rayleigh scattering method for the determination of polyvinylpyrrolidone using eosin Y as the probe

The intensities of resonance Rayleigh scattering (RRS) of poly (vinyl pyrrolidone) (PVP) and of eosin Y (EY) are weak in solutions of pH 2.9 to 3.4. If reacted with each other, the intensities of RRS are largely enhanced and new RRS bands appear at 276 nm and 320 nm. The intensity at 276 nm is linearly related to the concentration of PVP in the range from 0.10 to 1.6 μg mL^-1. The correlation coefficient is 0.9987, and the detection limit is 28.7 ng mL^-1. The binding mode between PVP and EY was studied by RRS, and by absorption and fluorescence spectroscopy. The optimum reaction conditions and some potential interferences were investigated. The method displays good selectivity and was applied to the determination of PVP in beer.     

A Highly Sensitive Resonance Rayleigh Scattering Method for the Determination of Vitamin B1 with Gold Nanoparticles Probe

In weakly acidic buffer medium, vitamin B₁ (VB₁) interacts with gold nanoparticles to form a binding product, which resulted in a significant enhancement of resonance Rayleigh scattering (RRS) intensity and the appearance of a new RRS spectrum. The maximum RRS peak was at 368 nm, and there are three smaller scattering peaks that were at 284 nm, 440 nm and 495 nm, respectively. The enhanced RRS intensity (ΔI) was directly proportional to the concentration of VB₁ in the range of 0–2.8 × 10⁻⁷ mol L⁻¹. The method had high sensitivity and its detection limit (3σ) was 0.9 ng mL⁻¹. The optimum conditions and the influencing factors have been investigated. The method had good selectivity, which could be observed from the influence of coexisting substances. A sensitive, simple and fast RRS method for the determination of VB₁ with gold nanoparticle probe has been developed. In addition, the reasons for RRS enhancement were discussed.     

Determination of dextran sulfate sodium with crystal violet by triple-wavelength overlapping resonance Rayleigh scattering

A triple-wavelength overlapping resonance Rayleigh scattering (TWO-RRS) method was developed to detect dextran sulfate sodium (DSS) with crystal violet (CV). At pH 10.0 Britton Robinson buffer solution medium, the interaction of CV with DSS occurred which greatly enhanced the RRS intensity with the new RRS peaks appearing at 340, 501 and 671 nm and all these three peaks enhanced with the increase of DSS concentration in the range of 0.04-2.5 microg ml(-1) and the detection limit for the three single peaks was 0.024, 0.027, and 0.027 microg ml(-1), respectively, whereas that of the TWO-RRS method was 0.013 microg ml(-1). The TWO-RRS method was found to have much better flexibility and high sensitivity than the single-wavelength method. In this paper, the interaction conditions were optimized. The affecting factors and characteristics of RRS for the interaction of DSS with CV were investigated and a sensitive method for the determination of trace amounts of DSS using the TWO-RRS method was developed.     

Spectrofluorimetric method for determination of aluminium with chromotropic acid and its application to water samples

A rapid and sensitive method for the trace level determination of aluminium based on the formation of a 1:1 complex with chromotropic acid (1,8-dihydroxynaphthlene-3,6-disulfonic acid) in an methanol medium is reported. The fluorescence intensity of the system was 50 times greater than that of the system without aluminium. This method is very sensitive and selective for the direct determination of aluminium ion. The fluorescence is excited at 346 nm and measured at 370 nm. The optimum conditions are a chromotropic acid concentration of 5.0 ml (1.0x10(-4) M) and pH 4.0+/-0.5 (acetic acid-sodium acetate buffer). The fluorescence intensity is a linear function of the concentration of Al(III) in the range 2-100 ng ml(-1) and the detection limit is 1.0 ng ml(-1). The method has been applied successfully to the determination of trace amount of Al(III) in tap, river and sea-water samples.     

Interaction of [HgX4]2- with berberine by absorption and resonance Rayleigh-scattering spectra and their analytical applications.

In a diluted H2SO4 solution, Hg(II) reacts with halide anions X- (including Cl-, Br- and I-) to form anionic complexes [HgX4]2- that can further react with berberine to form ion-association complexes of [Ber]2[HgX4]. As a result, the absorption spectra change, their maximum absorption wavelengths are at 230 nm for [Ber]2[HgCl4], 278 nm for [Ber]2[HgBr4] and 300 nm for [Ber]2[HgI4]. However, among the three complexes, only [Ber]2[HgI4] can lead to distinctly enhanced resonance Rayleigh scattering (RRS), and a new RRS spectrum appears. The maximum RRS wavelength is located at 397 nm, and the RRS intensity is proportional to the concentration of berberine in the range of 0-2.5 microg mL-1. The optimum conditions, the influence factors for the reaction and the effects of coexisting substances have been investigated. A new, simple and fast RRS method for the determination of berberine based on the ion-association reaction of [HgI4]2- with Ber+ was developed. The method has high sensitivity and good selectivity; the detection limit for berberine (3 sigma/K) is 7.22 ng mL-1. The method can be applied to the determination of berberine in some Chinese patent drug and the extracts of Coptis Chinensis. Furthermore, the mechanism of the reaction and the reasons for RRS enhancement have been discussed.     

Resonance Rayleigh scattering spectra, non-linear scattering spectra of malachite green-12-tungstophosphoric acid system and its analytical application in fish

In 0.1 molL(-1) (pH 1.0) HCl medium, 12-tungstophosphoric acid (TP) reacted with malachite green (MG) to form an ion-association complex. As a result, the new spectra of RRS, SOS and FDS appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, SOS and FDS were located at 334 nm, 586 nm and 330 nm, and the scattering intensities were proportional to the concentration of MG. Based on it a new method for the determination of MG has been established. The detection limits (3σ) of these methods were in the range of 3.7-27 ng mL(-1). The RRS, SOS, and FDS characteristics, absorption spectrum characteristics and optimum reaction conditions of the system were discussed. Effects of coexistent substances were tested, and the results demonstrated that this method had good selectivity. It has been applied to the determination of malachite green residues in fish flesh with satisfactory results. The reaction mechanism and reasons of RRS enhancement are discussed.     

Study on the interaction between torasemide and 12-tungstophosphoric acid by resonance Rayleigh scattering and resonance nonlinear scattering spectra and its analytical applications

In pH 0.6-1.1 HCl-NaAc buffer solution, torasemide (TOR) reacted with TP to form a 3:1 ion-association complexes. As a result, not only the absorption spectra were changed, but also the intensities of resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS) were enhanced greatly. The maximum RRS, SOS and FDS wavelengths were located at 370, 333, 776 nm, respectively. Under given conditions, the intensities of RRS, SOS and FDS were all directly proportional to the concentration of TOR. The detection limits of RRS, SOS and FDS were 0.7173 ng mL(-1), 7.007 ng mL(-1) and 10.90 ng mL(-1). The optimum conditions and the effects of coexisting substances on the reaction were investigated. The results showed that the method had good selectivity. Therefore, a highly sensitive, simple and quick method has been developed for the determination of TOR. The method can be applied satisfactorily to the determination of TOR in tablets and urine samples.     

Determination of pyridoxal 5'-phosphate in human serum by reversed phase high performance liquid chromatography combined with spectrofluorimetric detection of 4-pyridoxic acid 5'-phosphate as a derivative

A very sensitive spectrofluorimetric method for the determination of pyridoxal 5'-phosphate (PLP) in human serum is described. The specificity is based on the selective oxidation of PLP to 4-pyridoxic acid 5'-phosphate with potassium cyanide. Separation of the highly fluorescent 4-pyridoxic acid 5'-phosphate is achieved by reversed-phase high-performance liquid chromatography. Specificity is improved by a careful choice of fluorescence filters, maximised at the excitation (325 nm) and emission (418 nm) wavelengths of 4-pyridoxic acid 5'-phosphate. The detection limit for the reaction is 0.22 ng ml(-1). For quantification, the serum is spiked with PLP before protein precipitation with 3.3% m/V trichloroacetic acid. The method can be used for the determination of PLP in serum, even in vitamin B6 deficient patients. The mean value for human serum PLP from 30 healthy adults was found to be 14.6 +/- 4.8 ng ml(-1) (mean +/- standard deviation).