甲基绿褪色光度法测定琥乙红霉素

在pH 7.8的磷酸盐缓冲溶液中,琥乙红霉素和甲基绿在50℃下可以反应形成稳定的离子缔合物。冷却至室温后以水做参比测定体系的吸收光谱,发现琥乙红霉素溶液在550~670 nm几乎无吸收,甲基绿在此区域有强烈的吸收,甲基绿与琥乙红霉素生成的离子缔合物的吸光度与甲基绿相比有明显降低,最大褪色波长在634 nm附近,且吸光度变化ΔA与琥乙红霉素的浓度成正比。琥乙红霉素的质量浓度在0.0009~0.1530 mg/mL范围内服从Beer定律,线性回归方程为:A=-3.037ρ+0.0355,r=0.9995;对10.00 mL 5.0×10-3mg/mL琥乙红霉素测定6次,RSD=0.6%,在634 nm测得ε=6.19×104L·mol-1·cm-1。研究了琥乙红霉素-甲基绿反应体系的光谱特性、反应的影响因素、共存物质的影响,做了反应的条件优化实验,对所建立的方法进行了一些初步的分析应用。在实验基础上,建立了测定琥乙红霉素的褪色分光光度法,检出限为0.21μg/mL,可用于琥乙红霉素片中琥乙红霉素含量的测定。     

分光光度法快速测定食品中糖精钠含量

基于在硫酸介质中,次甲基蓝与糖精钠反应生成憎水型离子缔合物,且该缔合物可被氯仿定量萃取,提出了分光光度法测定食品中糖精钠含量。在室温下,当0.2 mol.L-1硫酸用量为2.5 mL,0.04 mol.L-1次甲级蓝溶液用量为2 mL时,糖精钠的质量浓度在15 mg.L-1范围内与其吸光度呈线性关系,检出限(3s/k)为0.11 mg.L-1。用此法测定几种食品中糖精钠含量,回收率在100.1%~114.0%之间,相对标准偏差(n=6)均小于5.0%。     

溶剂浮选-间接光度法测定抗坏血酸

于pH 7.0的磷酸盐缓冲介质中,CTMAB＋及I3-离子间借静电引力形成离子缔合物,可将其浮选入5.0 mL苯中,此缔合物在溶剂中,于365 nm处有吸收峰,较简单的I3^-离子在相同条件下的吸收峰（350 nm）红移了15 nm。在此溶液体系中存在抗坏血酸时使离子缔合物产生褪色反应,且在抗坏血酸浓度在25μg/50 mL以内时与吸光度的降低值（ΔA）间呈线性关系。在抗坏血酸浓度为6.0μg/50 mL时连续测定6次,所得结果的RSD为1.2%,回收率在96%-101%之间。     

藏红T褪色分光光度法测定微量肝素

在pH 5.02的Britton-Robinson缓冲溶液中,肝素与碱性吩嗪染料藏红T形成离子缔合物,染料发生明显的褪色,体系吸光度的降低与肝素钠质量浓度成正比,0~2μg/mL范围内符合比耳定律,比吸光系数为0.36×103L.g-1.cm-1。研究了表面活性剂和共存物质的影响,表明方法选择性好。用于肝素钠注射液效价的测定。     

孔雀绿与磷钒钼杂多酸显色反应的研究

在稀H2SO4介质中,磷酸盐与钼酸盐和偏钒酸盐反应形成磷钒钼杂多酸,杂多酸再与孔雀绿缔合形成四元有色络合物,能稳定存在于含聚乙烯醇的水溶液中。缔合物的最大吸收位于590nm波长处,摩尔吸收系数ε=1.7×105L·mol-1·cm-1,P(V)的质量浓度在0～0.12μg mL范围内与吸光度成正比。研究了显色反应的适宜条件、共存离子的影响和缔合物的组成。方法已用于合成试样中磷的测定。     

甲基绿分光光度法测定高氯废水中的铊

在0.08 mol/L氢溴酸介质中,Tl Br4–和甲基绿形成稳定的蓝紫色缔合物,该缔合物被乙酸异戊脂萃取后用分光光度法测定高氯废水中的铊。在最佳吸收波长590 nm处,铊的质量浓度在0~5μg/(10 mL)范围内与吸光度呈良好的线性关系,相关系数为0.998 7,检出限为0.005 3μg/mL。测定结果的相对标准偏差为1.99%~3.38%(n=6),样品加标回收率为96.55%~98.04%。该方法操作简单,可应用于高氯废水中铊的测定。     

曙红Y探针褪色分光光度法测定长春瑞滨

在pH 2.2的Britton-Robinson缓冲体系中,长春瑞滨与曙红Y反应,形成离子缔合物能使染料发生明显的褪色反应。最大褪色波长位于520 nm,且在0.25~15μg/mL范围内,吸光度降低与长春瑞滨质量浓度成正比,表观摩尔吸光系数为7.7×104L·mol-1·cm-1。由此建立了测定长春瑞滨的吸收光谱新方法,可应用于注射液中长春瑞滨的测定。     

硫堇褪色光度法测定微量肝素

在pH 4.10的Britton-Robinson缓冲溶液中,肝素与碱性吩噻嗪染料硫堇形成离子缔合物时,染料发生明显的褪色。体系吸光度的降低与肝素钠浓度成正比,肝素的质量浓度在0~60μg/25 mL范围内符合比耳定律,摩尔吸光系数为3.58×106L.mol-1.cm-1。研究了表面活性剂和共存物质的影响,表明方法选择性好。用于肝素钠注射液效价的测定,相对标准偏差小于3%,回收率为96.5%~101.9%。     

在PVA存在下Os-SnCl_2-亮绿离子缔合体系的研究高纯镍中微量Os的测定

本文研究了Os-SnCl_2-PVA-亮绿离子缔合体系的显色反应,摩尔吸光系数ε_(434)为5.6×10~6L·mol~(-1)·cm~(-1),锇含量在0.1～0.7μg/25mL范围内遵守比耳定律,室温下显色后,吸光度在110min内稳定。研究了30种外来离子的影响,并进行了高纯镍中微量锇的测定。     

紫尿酸显色分光光度法测定盐酸氯丙嗪片剂含量

建立了以紫尿酸为显色剂测定盐酸氯丙嗪的光度法。在弱酸性条件下,Fe(Ⅲ)被盐酸氯丙嗪定量还原成Fe(Ⅱ),Fe(Ⅱ)在碱性条件下与紫尿酸反应形成不稳定的蓝色配阴离子,该配阴离子与盐酸氯丙嗪形成稳定的蓝色离子缔合物,该离子缔合物的最大吸收波长位于635 nm,其表观摩尔吸光系数ε=2.62×104 L/(mol·cm),盐酸氯丙嗪质量浓度在0.5~10.0 mg/L范围内与体系的吸光度呈良好的线性关系,线性相关系数为0.999 2。测定结果的相对标准偏差为1.02%~2.65%(n=5),加标回收率为91.0%~95.0%。该法灵敏度较高、选择性及重现性良好,可用于片剂中盐酸氯丙嗪含量的测定。     

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.     

Determination of two antibacterial binary mixtures by chemometrics-assisted spectrophotometry

Simple chemometrics-assisted spectrophotometric methods are described for determination of 2 antibacterial binary mixtures. The mixtures are composed of norfloxacin in combination with tinidazole and erythromycin (as ethylsuccinate ester or stearate salt) in combination with trimethoprim. The normal UV absorption spectra of each pair of drugs in the studied mixtures, in the range of 200-400 nm, showed a considerable degree of spectral overlapping: 77.5% for the norfloxacin-tinidazole mixture and 84.3% for the erythromycin-trimethoprim mixture. Resolution of the norfloxacin-tinidazole mixture and trimethoprim in the presence of erythromycin was accomplished successfully by using zero-crossing first derivative (1D), classical least-squares (CLS) regression analysis, and principal component regression (PCR) analysis methods. In addition, an alternative simple and accurate colorimetric method was developed for the determination of erythromycin in the presence of trimethoprim using 2,4-dinitrophenylhydrazine. All variables affecting the development of the colored chromogen were studied and optimized, and the product was measured at 526-529 and 538-542 nm for erythromycin stearate and erythromycin ethylsuccinate, respectively. For zero-crossing, first derivative technique Beer's law was obeyed in the general concentration range of 2-50 microg/mL for norfloxacin, tinidazole, and trimethoprim with good correlation coefficients (0.9994-0.9996). Overall limits of detection (LOD) and quantification (LOQ) ranged from 0.59 to 2.81 and 1.96 to 9.33 microg/mL, respectively. The obtained results from CLS and PCR were compared with those obtained from a 1D spectrophotometric method. With the exception of erythromycin, overall recoveries in the average range of 97.33-103.0% were obtained with a considerable degree of accuracy when the suggested methods were applied to analysis of synthetic binary mixtures, some commercial dosage forms such as tablets and oral suspension without interference from the commonly encountered excipients and additives. For the colorimetric method, Beer's law was obeyed in the general concentration range of 7.21-28.84 microg/mL erythromycin with good correlation coefficients (0.9980-0.9996). Overall LOD and LOQ ranged from 0.73 to 1.65 and 2.43-5.49 microg/mL, respectively. Erythromycin derivatives were determined in the commercial dosage form, without interference from trimethoprim-encountered excipients and additives. The obtained results, with both chemometric and colorimetric methods, have been compared with those obtained from reported methods, and proper F- and t-values were observed, indicating no significant difference between the results of the suggested methods and reported method(s). The good percentage recoveries and proper statistical data obtained proved the efficiency of the proposed procedures for the determination of the studied drugs in their binary mixtures as well as in the commercial dosage forms with quite satisfactory precision.     

溶胶-凝胶法制备红霉素印迹固相萃取材料及其选择性吸附

以红霉素为模板分子,采用溶胶-凝胶印迹技术,合成对红霉素具有特异选择识别性能的印迹聚合材料.采用红外光谱、扫描电子显微镜、热重分析以及比表面积测定技术对印迹聚合物的结构和表面性能进行详细探讨,结果表明所得印迹聚合物比表面积为266.2m2/g,粒径为600nm左右的颗粒材料.选择3种抗生素类药物进行选择吸附研究,结果表明,该聚合物对红霉素的分离因子最高达到2.20.优化固相萃取条件,结果表明用甲醇:乙酸(75:25,V/V)作为洗脱剂时对红霉素的洗脱效果最好.结合液相色谱技术,该印迹材料成功的分离和富集红霉素肠溶片中的红霉素,回收率达到104.5%。     

离子液体中卤素离子杂质的离子色谱-直接电导检测法分析

研究了离子色谱-直接电导检测法分离测定离子液体中的卤素离子(F~-、Cl~-、Br~-)杂质.采用Shim-pack IC-A3阴离子交换色谱柱,考察了淋洗液种类及浓度、流速和色谱柱温度对分离测定的影响.最佳色谱条件为:以1.25 mmol/L邻苯二甲酸氢钾为淋洗液,流速1.5 mL/min,色谱柱温45 ℃.在此条件下可以基线分离卤素离子,且NO~-_3、BF~-_4、SO~(2-)_4不干扰测定.该法测定卤素离子的检出限(S/N=3)为0.02 ～0.11 mg/L,峰面积的相对标准偏差(n=5)不大于0.7%,F~-、Cl~- 和Br~- 的标准曲线的线性范围分别为0.1 ～50、0.1 ～50、0.5 ～100 mg/L.将方法用于烷基咪唑四氟硼酸盐离子液体中卤素离子杂质的测定,加标回收率为98% ～102%.     

锆-氟-7-碘-8-羟基喹啉-5-磺酸-EDTA-表面活性剂体系的荧光光度研究

在pH5.5～7.0的HAc-NaAc缓冲溶液中,锆与氟、7-碘-8-羟基喹啉-5-磺酸(H_2QSI)、EDTA及十六烷基三甲基溴化铵(CTMAB)形成五元荧光络合物,其组成为Zr(Ⅳ):F:H_2QSI:EDTA:CTMAB=1:2:1:1:4.络合物的最大激发波长(λ_(ex))为365nm,最大发射波长(λ_(em))为 500 nm.由此建立了锆的选择性好、灵敏度高的荧光测定新方法.方法的检测限为 0.8μg/L.测锆的线性范围为 0.0016～1.04 mg/L.应用于合金中锆的测定,结果满意.     

HPLC determination and pharmacokinetic study of tenatoprazole in dog plasma after oral administration of enteric-coated capsule

A simple, sensitive and selective high-performance liquid chromatographic (HPLC) method with UV detection (306 nm) was developed and validated for determination of tenatoprazole, a novel proton-pump inhibitor, in dog plasma. Tenatoprazole and internal standard (pantoprazole) were extracted into diethyl ether and separated using an isocratic mobile phase of 10 mm phosphate buffer (pH4.7)-acetonitrile (70:30, v/v) on a Diamonsil C(18) column (150 x 4.6 mm, 5 microm). The retention times for tenatoprazole and internal standard were 7.1 and 12.3 min, respectively. No endogenous interferences were observed. This HPLC method was fully validated. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 20%. A linear range of 0.02-5.0 microg/mL was established. The interday and intraday precisions were within RSD 13.4-10.1 and 4.6-1.4%, respectively. This method developed can be easily applied to the pharmacokinetic study of tenatoprazole in dog plasma after oral administration of an enteric-coated capsule. The plasma concentration of tenatoprazole from six dogs showed a mean C(max) of 2.63 microg/mL at T(max) of 1.89 h. The bioavailability of tenatoprazole was improved by administration of enteric-coated capsule.     

Separation and pre‐concentration of glucocorticoids in water samples by ionic liquid supported vortex‐assisted synergic microextraction and HPLC determination

We have developed a synergic microextraction procedure based on ionic liquid for the pre‐concentration and determination of glucocorticoids in water samples. Using nonionic surfactant Triton X‐100 (TX‐100) as synergic reagent, 1‐butyl‐3‐methylimidazolium hexa‐fluorophosphate accomplished extraction rapidly without heating in water bath. One key property of ionic liquids that highlights their potential is their wide liquid temperature range. The improved extraction was named as ionic liquid supported vortex‐assisted synergic microextraction. Compared with the traditional liquid–liquid extraction and cloud point extraction, ionic liquid supported vortex‐assisted synergic microextraction was accomplished in 8 min with considerably high recovery. The proposed method greatly improved the sensitivity of HPLC for the determination of glucocorticoids. The results obtained indicated a good linearity with the correlation coefficient of 0.997 over the range of 0.6–300 ng/mL and high sensitivity with LODs of 4.11, 9.19, and 7.50 ng/mL for hydrocortisone butyrate, beclomethasone dipropionate, and nandrolone phenylpropionate, respectively. The RSD of the method was 1.57–1.81% (n = 6) with enrichment factor of 99.85, and good recovery (≥97.24%). The method was successfully applied to the determination of glucocorticoids in mineral water, water of Dianchi lake, and tap water samples.     

Ionic liquid‐based microwave‐assisted surfactant‐improved dispersive liquid–liquid microextraction and derivatization of aminoglycosides in milk samples

A green and simple method, ionic liquid‐based microwave‐assisted surfactant‐improved dispersive liquid–liquid microextraction and derivatization was developed for the determination of aminoglycosides in milk samples. Nonionic surfactant Triton X‐100 and ionic liquid 1‐hexyl‐3‐methylimidazolium hexafluorophosphate were used as the disperser and extraction solvent, respectively. Extraction, preconcentration, and derivatization of aminoglycosides were carried out in a single step. Several experimental parameters, including type and volume of extraction solvent, type and concentration of surfactant, microwave power and irradiation time, concentration of derivatization reagent, and pH value and volume of buffer were investigated and optimized. Under the optimum experimental conditions, the linearities for determining the analytes were in the range 0.4–10.0 ng/mL for tobramycin, 1.0–25.0 ng/mL for neomycin, and 2.0–50.0 ng/mL for gentamicin, with the correlation coefficients ranging from 0.9991 to 0.9998. The LODs for the analytes were between 0.11 and 0.50 ng/mL. The present method was applied to the analysis of different milk samples, and the recoveries of aminoglycosides obtained were in the range 96.4–105.4% with the RSDs lower than 5.5%. The results showed that the present method was a rapid, convenient, and environmentally friendly method for the determination of aminoglycosides in milk samples.     

Electrogenerated chemiluminesence method for the determination of riboflavin at an ionic liquid modified gold electrode

A highly sensitive electrogenerated chemiluminescence (ECL) method for the determination of riboflavin was developed based on the enhancement of ECL intensity of lucigenin at room temperature ionic liquids (RTILs) modified gold electrode. RTILs modified gold electrode exhibited excellent electrochemical and ECL property to lucigenin system and the ECL intensity of lucigenin was greatly enhanced by riboflavin. The characterization of the RTILs modified electrode and the attractive performance of the sensitive ECL method for the determination of riboflavin were investigated. Under the optimized conditions, the ECL intensity was directly proportional to the concentration of riboflavin in the range from 5.0×10(-10) g/mL to 1.0×10(-8)g/mL with the detection limit of 1×10(-10) g/mL. The method has been applied to the determination of riboflavin in the pharmaceutical preparations with satisfactory recovery from 96% to 101%. This work demonstrates that the incorporation of ECL method with RTILs modified electrode is a promising strategy for the determination of organic compounds with high sensitivity and good reproducibility.     

Ionic liquid for single‐drop microextraction followed by high‐performance liquid chromatography‐ultraviolet detection to determine carbonyl compounds in environmental waters

A sensitive method based on ionic liquid for single‐drop liquid microextraction coupled with HPLC‐UV was developed for the determination of carbonyl compounds in environmental waters using 1‐octyl‐3‐methylimidazolium hexafluorophosphate [C₈min][PF₆] as extraction solvent and 2,4‐dinitrophenylhydrazine as derivatizing agent. The extraction parameters affecting the enrichment factors such as solvent volume, pH, extraction time and salt concentration were investigated. A homemade funnel form polytetrafluoroethylene sleeve was fixed at the tip of the syringe needle and this allowed the use of 10 μL drop of ionic liquid for direct immersion extraction. Under the optimal conditions, the remarkable enrichment factors up to 150‐fold were obtained depending on the target analytes. The method has been validated when rectilinear relationship was obtained between the concentrations of analytes and peak area in the range of 5–100 ng/mL, the correlation coefficients were from 0.995 to 0.998, and the limit of detection was in the range of 0.04–2.03 ng/mL. The method was applied to monitor the concentration of carbonyl compounds in environmental waters with spiked recovery in the range of 84.2–106.9%.