Sensitive Synchronous Spectrofluorimetric Study of Certain Sunscreens Using Fluorescence Enhancers in Cosmeceutical Formulations

Synchronous spectrofluorimetric methods could be successfully adopted for simultaneous determination of Octinoxate (OMC), Avobenzone (AVO), Octyltriazone (OT), and Phenyl benzimidazole sulfonic acid (PBSA) in moisturizing sunscreen lotion, utilizing β-CD as fluorescence enhancer, and determination of Avobenzone (AVO), Homosalate, Tinosorb M and Phenyl benzimidazole sulfonic acid (PBSA) in presence of Octocrylene (OCR) in whitening sunscreen cream, using micellar medium of Sodium Dodecyl Sulfate (SDS) to enhance fluorescence intensity. For first product, zero order synchronous spectrofluorimetric method was used for determination of OMC and AVO, and derivative synchronous spectrofluorimetric technique was utilized for OT and PBSA in quaternary mixture. Linear calibration curves were obtained in a concentration range of 0.5–8 μg mL^??1 for OMC and AVO, and in range of 0.05–3 μg mL^??1 for OT and 0.001–5 μg mL^??1 for PBSA, by measuring the fluorescence at 370, 405, 333.2 and 340.6 nm, respectively. For second product, first derivative synchronous fluorescence method was used for each UV-filter. A linear calibration curves were obtained in a concentration range of 0.5–8 μg mL^??1 for AVO, in range of 0.1–8 μg mL^??1 for Homosalate, 2–10 μg mL^??1 for Tinosorb M and 0.001–5 μg mL^??1 for PBSA, by measuring the fluorescence at 409.8, 373, 307.2 and 316.8 nm, respectively. The detection limits are well below the maximum admissible concentration. The proposed methods were validated according to ICH guidelines and successfully applied to determine sunscreens in pure form and in Cosmeceutical formulations. All the results obtained were compared with those of published methods, where no significant difference was observed.     

同步扫描荧光光谱法同时测定阿司匹林和水杨酸

建立了同步扫描荧光光谱法单次扫描同时测定阿司匹林和水杨酸双组分的方法。荧光光度计同步扫描时,得到两组分互不干扰的荧光峰,借此分别测定两组分的含量。阿司匹林和水杨酸浓度分别在4.0×10-6～1.0×10-4 mol·L-1, 8.0×10-7～1.0×10-4 mol·L-1范围内与荧光强度呈线性关系,相关系数分别为0.994 9和0.997 5,水杨酸的检测限为4.0×10-7 mol·L-1。该法简单、快速准确、易操作,可用于药物制剂中阿司匹林和水杨酸的同时测定。     

Determination of Ubiquinone in Blood by High-Performance Liquid Chromatography with Post-Column Fluorescence Derivatization Using 2-Cyanoacetamide

It was shown that ubiquinone (CoQ₁₀) and ubiquinol (CoQ₁₀H₂) produce fluorescence products under alkaline conditions when reacted with 2-cyanoacetamide. The reaction mixture from CoQ₁₀ gave fluorescence with excitation and emission maximum wavelengths at 442 nm and 549 nm, respectively. This reaction was considered to proceed via Craven’s reaction. Moreover, 2-cyanoacetamide was shown to be a useful reagent for high-performance liquid chromatography (HPLC) with post-column fluorescence derivatization of CoQ₁₀ and CoQ₁₀H₂ in blood. CoQ₁₀ showed a linear response in the range of 0.32–1276 ng, and the detection limit (S/N = 3) was 0.16 ng. Moreover, the sample pretreatment by deproteinization and extraction of CoQ₁₀ and CoQ₁₀H₂ from plasma using 1-propanol with potassium formate was effective for excellent separation of CoQ₁₀ and CoQ₁₀H₂ from other fluorescent substances in the blood. This simple and rapid pretreatment was considered to minimize the oxidation of CoQ₁₀H₂. On the other hand, CoQ₁₀ and CoQ₁₀H₂ in plasma samples obtained by finger prick were detected, as in venous blood obtained by venipuncture. Our method involving the simple and rapid collection of plasma by finger prick and sample pretreatment is thought to be applicable for the determination of CoQ₁₀H₂/total CoQ₁₀ ratio as a biomarker of oxidative stress.     

Simultaneous Determination of Acetylsalicylic Acid and Caffeine in Pharmaceutical Formulation by First Derivative Synchronous Fluorimetric Method

A sensitive, rapid, and specific assay has been developed for the simultaneous determination of acetylsalicylic acid and caffeine in commercial tablets based on their natural fluorescence. The mixture of these drugs was resolved by first derivative synchronous fluorimetric technique using two scans. At Δλ=106 nm, using first derivative synchronous scanning, only acetylsalicylic acid yields a detectable signal at 316 nm (peak to zero method) which is unaffected by caffeine. At Δλ=30 nm, the signal of caffeine at 288 nm (peak to zero method) is not affected by acetylsalicylic acid. The range of application is between 0.021 and 41.62 μg ml⁻¹ (correlation coefficient, R=0.9995) for acetylsalicylic acid and between 0.4486 and 44.86 μg ml⁻¹ (correlation coefficient, R=0.99786) for caffeine. The recovery range of 98.40–102% for acetylsalicylic acid and 90–100.5% for caffeine from their synthetic mixture was reported. Overall recovery of both compounds about 97–99% for acetylsalicylic acid and 97–98% for caffeine was obtained from real sample analysis. The detection limits are 0.0013 μg ml⁻¹ and 0.0306 μg ml⁻¹ for acetylsalicylic acid and caffeine, respectively. The relative standard deviation (n=10) for 20 μg ml⁻¹ of acetylsalicylic acid is 2.75% and for 2.2 μg ml⁻¹of caffeine is 1.7%.     

同步荧光法测定生物样品中蛋白含量的研究

基于5-甲基尿苷(5-Methyluridine)与血清白蛋白(HSA)相互作用,导致血清白蛋白的同步荧光发生特异性变化,且体系的同步荧光强度和溶液中HSA的浓度呈良好的线性关系,建立了以5-甲基尿苷为分子探针,运用固定波长同步荧光光谱法测定生物样品中蛋白质总含量的新方法。文章考察了Δλ值、反应介质、试剂用量、离子浓度、试剂加入顺序、反应时间、反应温度等因素对体系同步荧光的影响。在选定的最佳实验条件下,体系的同步荧光强度与血清白蛋白在1.38～575.2 μg·mL-1范围内的线性相关系数为0.998 1,方法的检测限可达0.12 μg·mL-1。运用本方法对人血清、唾液和尿液等生物样品进行测定并进行加标回收实验,回收率在98.7%～103.8%之间。对11份5-甲基尿苷空白溶液进行平行测定,其相对标准差为1.56%。还考察了一些常见离子和有机物存在时对蛋白质测定的影响。结果显示,本方法具有简单、快速、灵敏度较高、线性范围宽、体系稳定、精密度高、重现性好等优点。该法可直接用于血清、唾液和尿样等生物样品中蛋白质总量的快速测定,结果令人满意。     

Highly Sensitive Synchronous Fluorescence Measurement of Danofloxacin in Pharmaceutical and Milk Samples Using Aluminium (III) Enhanced Fluorescence

A simple, rapid and sensitive constant wavelength synchronous fluorescence method is developed for the determination of danofloxacin (DAN) in pharmaceutical formulations and its residue in milk based on Al(III) enhanced fluorescence. The synchronous fluorescence intensity of the system is measured at 435?nm using ? λ?=?80?nm and an excitation wavelength of 280?nm. A good linear relationship between enhanced fluorescence intensity and DAN concentration is obtained in the range of 3-100?ng?mL(-1)(r (2)?=?0.9991). The limit of detection (LOD, S/N?=?3) of the present method is 0.9?ng?mL(-1). The proposed method can be successfully applied to the determination of DAN in pharmaceutical formulations and in milk without serious interferences from common excipients, metal ions and other co-existing substances. The method can be used as a rapid screening to judge whether the DAN residues in milk exceed Maximum Residue Limits (MRLs) or not.     

Second-Derivative Synchronous Fluorescence Spectroscopy for the Simultaneous Determination of Fluphenazine Hydrochloride and Nortriptyline Hydrochloride in Pharmaceutical Preparations

A rapid, simple, and highly sensitive second-derivative synchronous fluorimetric (SDSF) method has been developed for the simultaneous analysis of binary mixtures of fluphenazine hydrochloride (FLZ) and nortriptyline hydrochloride (NTP) in their co-formulated tablets. The method is based upon measurement of the native fluorescence of these drugs at constant wavelength difference (Δλ)?=?120 nm in acetic acid. The different experimental parameters affecting the fluorescence intensity of the studied drugs were carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the range of 0.25–3.0 and 1–10 μg/ml for FLZ and NTP respectively, with lower detection limits (LOD) of 0.05 and 0.18 μg/ml and quantitation limits of 0.15 and 0.53 μg/ml for FLZ and NTP respectively. The proposed method was successfully applied for the determination of the studied compounds in their synthetic mixtures and in commercial co-formulated tablets. The results obtained were in good agreement with those obtained by the reference methods.     

Terbium Sensitized Luminescence for the Determination of Ketoprofen in Pharmaceutical Formulations

This paper explores an ultra-sensitive luminescence method for the determination of Ketoprofen (KP) in pharmaceutical formulations. The technique is indirect and exploits the luminescence enhancement of terbium (Tb³⁺) by complexation with KP (Tb³⁺–KP), which was monitored at respective excitation and emission wavelengths of λ _ex = 258 nm and λ _em = 549 nm. The effect of varying the Tb³⁺ concentration and using multiple solvents was examined to determine optimal experimental conditions. Maximum sensitization was accomplished in the presence of methanol where the most favourable condition for the formation of the complex was recorded at a level of 1.0 × 10⁻⁵ M of Tb³⁺. Under these optimum experimental conditions, linear calibration curve was obtained in the range of 2.8 × 10⁻⁷–3.1 × 10⁻⁶ M with a detection limit of 8.7 × 10⁻⁸ M. The technique was validated with ‘working’ reference standards and produced relative standard deviations < 2% indicating that the reproducibility was highly acceptable. The proposed method was successfully applied to assays of KP in pharmaceutical formulations with average recoveries of 92–98%. The results were found to be in good agreement with those obtained by HPLC. The method is highly suited for general applications of this nature.     

基于APTLD的猪肉中莱克多巴胺残留含量的三维同步荧光光谱快速测定

应用三维同步荧光光谱法结合交替惩罚三线性分解(APTLD)来建立猪肉中莱克多巴胺残留含量的定量测定模型,以实现猪肉中莱克多巴胺残留含量的快速测定。首先分析了莱克多巴胺的荧光光谱产生机理和样本的三维同步荧光光谱;其次对猪肉提取液中的莱克多巴胺荧光的浓度猝灭现象进行了分析;然后应用核一致诊断法确定了APTLD的三线性分解组分数为2,并建立了猪肉提取液中莱克多巴胺的相对荧光峰值强度与训练样本中莱克多巴胺的相对荧光峰值强度之间的标定曲线,用于待测样本中的相对荧光峰值强度的校正;最后,建立了基于APTLD的猪肉中莱克多巴胺残留含量的三维同步荧光光谱预测模型。试验结果表明,该方法可以较好的解决猪肉样本中莱克多巴胺与背景之间的同步荧光光谱严重重叠的问题,省去了一些烦琐的“化学分离”过程,模型预测集的决定系数(R2)和均方根误差(RMSEP)分别为0.986 3和0.496 6 mg·L-1,达到了猪肉中莱克多巴胺残留含量快速定量测定目的。     

New Spectrofluorimetric Method for Determination of Cephalosporins in Pharmaceutical Formulations

Simple, accurate and sensitive spectrofluorimetric method has been proposed for the determination of three cephalosporins, namely; cefixime (cefi), cephalexine (ceph), cefotaxime sodium (cefo) in pharmaceutical formulations. The method is based on a reaction between cephalosporins with 1, 2-naphthoquinone-4-sulfonic (NQS) in alkaline medium, at pH values of 12.0 for cefi and 13.0 for ceph and cefo to give highly fluorescent derivatives extracted with chloroform and subsequently measured at 600,580 and 580 nm after excitation at 520,455 and 490 nm for cefi, ceph and cefo respectively. The optimum experimental conditions have been studied. Beer’s law is obeyed over the concentrations of 10–35 ng/mL, 10–60 ng/mL and 20–45 ng/mL for cefi,ceph and cefo, respectively. The detection limits were 2.02 ng/mL, 2.09 ng/mL and 2.30 ng/mL for cefi, ceph and cefo, respectively, with a linear regression correlation coefficient of 0.9987, 0.9995 and 0.9991 and recoveries in range from 98.5-107.04, 95.17-101.00 and 95.00-109.55% for cefi, ceph and cefo, respectively. This method is simple and can be applied for the determination of cefi, ceph and cefo in pharmaceutical formulations in quality control laboratories.     

同步荧光光谱法测定石油中的晕苯

用苯做溶剂对原油样品进行逐级稀释,恒波长同步荧光法对原油样品中晕苯进行定性、定量分析。分别从溶剂选择、波长差、狭缝宽度等参数对其测定的光谱条件进行优化。实验结果表明：用苯为溶剂、Δλ=6nm,狭缝宽度为2.5nm,为原油样品中晕苯的最佳测试条件。所建立方法测定晕苯的线性范围为0.5—100μg/mL,校准曲线的相关系数r大于0.99,相对标准偏差小于3%（n=5）。该法分析快速、准确,对石化工厂中对原油样品中晕苯的快速检测具有一定的应用价值。     

利用同步荧光光谱快速鉴别潲水油

为快速鉴别潲水油,采用三维同步荧光光谱结合平行因子法解析潲水油的特征波长差(Δλ),并利用支持向量机建立潲水油鉴别模型。结果表明,潲水油的特征Δλ为60 nm;特征Δλ下的样品原始同步荧光光谱经过主成分分析提取5个主成分,以径向基函数(RBF)为核函数,利用网格搜索和6-fold交叉验证优化建模参数,得到惩罚因子C=512、核参数g=0.5,该条件下建立的模型对训练集和预测集的判别率均达到100%。采用同步荧光光谱可以快速、准确地鉴别潲水油。     

低温恒能量同步荧光法同时快速检测食品中多种多环芳烃

恒能量同步荧光法应用于多环芳烃的检测可以提高选择性,低温可使谱带呈指纹特征,提供常温光谱无法获得的光谱细节信息,有助于实现对复杂基体中多环芳烃的检测。文章结合恒能量同步荧光扫描技术与斯波斯基低温技术,建立了食品中多种多环芳烃的低温恒能量同步荧光同时快速分析方法。对低油脂样品直接用正辛烷浸泡,高油脂样品也只需要增加皂化萃取,即可进行光谱扫描来检测食品样中的多种多环芳烃。对两种类型的实际样进行加标回收实验,回收率为80.2%～98.9%,定量工作曲线线性较好(r≥0.993 8)。该方法选择性好、操作简便快捷、费用低廉。     

UV-Spectroscopic Determination of Mixtures of Tetramethrin and Piperonyl Butoxide in Pharmaceutical Formulations

Abstract

A simple rapid and accurate UV-spectroscopic method have been developed for determination of tetramethrin in presence of piperonyl butoxide, which are present in Licid^R, a newly introduced pharmaceutical drug in Egypt used as antilice, and antiscopis. The method is applicable in the concentration range of 1–12 μg.ml^?1 and 1–50 μg.ml^?1 for tetramethrin and piperonylbutoxide respectively. Average recoveries for tetramethrin and piperonyl butoxide in Licid^R spray and Licid^R lotion are 98.14 ± 0.3 – 103.88 ± 1.88 (Tetra), 103.78 ± 1.23 (piperonyl) and 100.62 ± 0.89 – 100.94 ± 1.10 (Tetra), 102.38 ± 1.02 (piperonyl) for the spray and lotion, respectively.     

铕-吡哌酸时间分辨荧光法检测DNA含量

在pH值为7.2的Tris-HCl缓冲溶液中,铕与吡哌酸反应形成配合物。该体系中加入鲱鱼精DNA分子作用后荧光强度显著增强,并且在一定浓度范围内,DNA浓度与其荧光强度呈良好的线性关系,据此建立了一种简单的测定DNA的时间分辨荧光分析新方法。考查了体系的时间分辨荧光光谱,通过与普通荧光光谱的对比突显了采用时间分辨荧光法的优势,并对反应条件进行了优化。该方法对DNA的检测限为0.03 mg·L-1(3σ),对浓度为4.0 mg·L-1的DNA进行11次平行测定,其相对标准偏差为0.3％。DNA的浓度在0.1～6.0 mg·L-1范围内与荧光强度呈良好的线性关系,线性方程为：ΔI=89.58c(mg·L-1)+0.920 5,线性相关系数r=0.999 6。此方法已应用于合成样品中DNA的测定,结果和加标回收率令人满意。     

Simultaneous Determination of Xanthopterin and Isoxanthopterin in Human Urine by Synchronous Fluorescence Spectroscopy

A simple, rapid, sensitive and selective method for simultaneously determining xanthopterin and isoxanthopterin content in human urine has been developed using synchronous fluorescence spectroscopy based on their intrinsic fluorescence. The synchronous fluorescence spectra were obtained with Δλ = 65 nm in a pH 8.5 KH₂PO₄-NaOH buffer solution. The detected wavelengths of quantitative analysis were set at 410 nm for xanthopterin and 325 nm for isoxanthopterin, respectively. Pretreatment of urine samples only was filtrated through a 0.45 μm membrane filter, which was free from the tedious separation procedures. Under optimized conditions, the limits of detection (LOD) were 0.94 ng/mL for xanthopterin and 0.48 ng/mL for isoxanthopterin. The recoveries ranged from 88.0% to 103.8 % for healthy and cancer urine samples, with coefficient of variation between 2.09% and 7.06%. The proposed method has been successfully applied to the simultaneous analysis for xanthopterin and isoxanthopterin in human urine. The results showed that the average level of isoxanthopterin was significantly elevated in urine excreted by stomach cancer patients (P < 0.01), while no significant change of xanthopterin level was found between stomach cancer patients and healthy individuals. This potentially indicates that an increase in amounts of isoxanthopterin can be associated with the presence of stomach cancer.     

同步荧光光谱法测定水中痕量萘和菲

同步荧光法具有选择性好、灵敏度高、干扰少等特点,可用于多组分多环芳烃混合物的同时测定,本文建立了恒定波长同步荧光光谱法同时测定水中萘和菲的新方法。研究了萘和菲在不同溶剂中的荧光光谱特性,确定了同步荧光的最优波长差。当Δλ=100 nm,萘和菲激发波长(λ_ex)分别为220.2和248.8 nm时,在0.5～25.0 μg·L-1浓度范围内,荧光强度与浓度呈现良好的线性关系,相关系数分别为0.999 5和0.999 7;萘和菲检出限均低于0.03 μg·L-1,回收率在98.0%～101.5%。该方法方便快捷,预处理简单,可用于水中萘、菲的快速测定。     

恒能量同步荧光光谱法测定食用油中多环芳烃

用12%（w/V）的氢氧化钾-乙醇溶液皂化食用油的脂肪酸,以环己烷萃取皂化液中的多环芳烃,经浓缩,柱层析纯化并浓缩,取微量试样液稀释后,通过选择合适能量差,建立了同步荧光法测定食用油中多环芳烃含量的新方法,其线性范围为5—1000ng.mL-1,检出限在0.04—15.21ng.mL-1之间,平均加标回收率在81.94%—90.06%之间。该方法具有快速、简便、准确等特点。     

卟啉全内反射同步荧光法测定蛋白质

应用全内反射与同步荧光相结合的技术,建立了利用蛋白质吸附在液-固界面上的同步荧光信号来测定本体蛋白质溶液浓度的新方法。其原理为meso-四(4-磺酸基苯基)卟啉(TPPS)标记牛血清蛋白(BSA)在石英界面的吸附后信号强度随本体溶液浓度的增加呈线性关系。方法的检出限是94 ng·mL-1。用于实际人血清蛋白样品的测定,结果令人满意。     

基于三维同步荧光光谱确定原油样品浓度的新方法

在对胜利油田原油样品进行不同浓度时的Δλ为40 nm的同步扫描荧光光谱的测量中,发现不同的浓度时的光谱不仅表现为峰高变化,峰位也有显著变化。综合整个光谱的峰高峰位等多因素,文章建立基于同步三维荧光光谱确定原油样品浓度的新方法,即采取二维三次卷积插值的方法获得连续的浓度三维荧光图谱,并与待测样品的同步光谱进行最小二乘法的谱线识别方法以确定其浓度,在10-4～1.0 g·L-1浓度范围内误差小于3％。与传统的石油荧光录井中所采用的二维发射荧光方法相比,文章提出的确定原油样品含油量的光谱方法的适用测量范围和测量精度均有大幅度的提高,可望在石油录井中得到应用。