Identification and estimation of the levo isomer in raw materials and finished products containing atropine and/or hyoscyamine

The belladonna alkaloids atropine sulfate and hyoscyamine sulfate, occasionally used as anticholinergic and antimuscarinic agents, have identical molecular formulas but different stereo configurations. Hyoscyamine sulfate contains almost 100% of the levo isomer, whereas atropine sulfate is composed of equal parts of dextro and levo isomers. It is believed that the therapeutic properties of these alkaloids are due exclusively or primarily to the levo isomer. Currently available methods determine only the total amount of atropine (hyoscyamine) sulfate. A method has been developed and is reported for the identification and estimation of the levo and dextro isomers of atropine and hyoscyamine. Reference solutions are prepared in methanol at the following weights per 100 mL: 8.0 mg atropine sulfate; 4.0 mg hyoscyamine sulfate; 7.0 mg scopolamine hydrobromide; and 10.0 mg homatropine methylbromide. Samples of raw materials are similarly prepared in methanol, commercial products are also extracted or diluted with methanol, and solutions are filtered. Liquid chromatography is used for separations on a 25 cm Chirobiotic T2 column. The mobile phase is prepared by mixing 3.0 mL acetic acid and 2.0 mL triethylamine with 1000 mL methanol. The injection volume is 100 or 200 microL; the flow rate is about 0.35 mL/min. Fluorescence detection is at 255 nm excitation and 285 nm emission. Scopolamine hydrobromide and hyoscyamine eluted after 20 and 60 min, respectively. Atropine sulfate generated 2 peaks after 60 and 65 min. Homatropine methylbromide also produced 2 peaks after 70 and 85 min. Samples tested in this study included raw materials and commercial tablets or injections containing belladonna alkaloids. In all cases, the percentage calculated was that of the levo isomer relative to the total amount of atropine (hyoscyamine) present.     

Determination of phenylephrine hydrochloride, chlorpheniramine maleate, and methscopolamine nitrate in tablets or capsules by liquid chromatography with two UV absorbance detectors in series

A procedure is presented for the simultaneous determination of phenylephrine HCI (PE), chlorpheniramine maleate (CM), and methscopolamine nitrate in commercial tablets or capsules by liquid chromatography (LC) with 2 UV absorbance detectors in series. Reference and sample solutions are prepared in methanol. LC separations are performed on a 7.5 cm Novapak silica column. The mobile phase is prepared by mixing 930 mL methanol with 70 mL of a 0.5% aqueous solution of 1-pentanesulfonic acid, sodium salt. The injection volume is 20 microL; the flow rate is approximately 1 mL/min. Retention times are approximately 1.5 min for PE, 3 min for CM, and 6 min for methscopolamine nitrate. One detector determines the first 2 compounds at 265 nm, but the third compound does not produce a detectable peak. The other detector set at 210 nm generates peaks for all 3 compounds, but only methscopolamine is within the recorder range; the other 2 compounds are exceedingly off scale. If it is not feasible or desirable to arrange 2 UV absorbance detectors in series, separate determinations can be made, one for the first 2 compounds and the other for the third component of the mixture. Two commercial samples of tablets and 2 commercial samples of capsules were analyzed by the proposed method. Recovery studies were also conducted with amounts of the 3 compounds ranging from 80 to 120% of the quantities present in the sample solutions.     

Application of high performance capillary electrophoresis on toxic alkaloids analysis

We employed CE to identify mixtures of the toxic alkaloids lappaconitine, bullatine A, atropine sulfate, atropine methobromide, scopolamine hydrobromide, anisodamine hydrobromide, brucine, strychnine, quinine sulfate, and chloroquine in human blood and urine, using procaine hydrochloride as an internal standard. The separation employed a fused-silica capillary of 75 microm id x 60 cm length (effective length: 50.2 cm) and a buffer containing 100 mM phosphate and 5% ACN (pH 4.0). The sample was injected in a pressure mode and the separation was performed at a voltage of 16 kV and a temperature of 25 degrees C. The compounds were detected by UV absorbance at wavelengths of 195 and 235 nm. All the ten alkaloids were separated within 16 min. The method was validated with regard to precision (RSD), accuracy, sensitivity, linear range, LOD, and LOQ. In blood and urine samples, the detection limits were 5-40 ng/mL and linear calibration curves were obtained over the range of 0.02-10 microg/mL. The precision of intra- and interday measurements was less than 15%. Electrophoretic peaks could be identified either by the relative migration time or by their UV spectrum.     

紫外分光光度法测定聚硫密封胶中二氧化钛

基于强酸性溶液中钛氧离子与H2O2发生显色络合反应的原理,建立了浓硫酸–硫酸铵消解–紫外分光光度法测定聚硫密封胶中TiO_2含量的方法。通过对酸液和显色剂用量,以及显色络合物稳定性的系统考察,确定浓硫酸用量为2 mL,双氧水用量为3 mL,检测波长为403 nm。二氧化钛质量浓度在0~130μg/mL范围内与其吸光度呈良好的线性关系,线性方程为A=5.047 8c–0.019 31,r~2=0.999 2,检出限为0.08μg/mL。检测结果的相对标准偏差为0.89%(n=5),3水平加标平均回收率为101.7%。该方法线性范围较宽、检出限低、重复性好,可用于聚硫密封胶中二氧化钛的定量分析。     

Determination of caffeine in tea samples by Fourier transform infrared spectrometry

A sustainable and environmentally friendly procedure has been developed for the FTIR determination of caffeine in tea leaf samples. The method is based on the extraction with ammonia and CHCl3 and direct determination of caffeine on the chloroform extracts using peak height absorbance measurements at 1658.5 cm(-1) and external calibration. The method provides a sensitivity of 0.2142 absorbance units mg(-1) mL and a limit of detection of 1 mg L(-1), corresponding to 0.002% m/m caffeine in tea leaves. As compared with a reference procedure, based on UV absorbance measurement at 276 nm after low pressure column chromatography, the developed procedure reduces the consume of CHCl3 by a factor of 10, that of NH4OH by a factor of 20 and avoids the use of diethyl ether and Celite. The time required to do the analysis of a sample is 15 minutes as compared with the 6 hours for the reference one.     

Liquid chromatographic analysis of cinchona alkaloids in beverages

A method for the determination of Cinchona extract (whose main components are the alkaloids cinchonine, cinchonidine, quinidine, and quinine) in beverages by liquid chromatography was developed. A beverage with an alcohol content of more than 10% was loaded onto an OASIS HLB solid-phase extraction cartridge, after it was adjusted to pH 10 with 28% ammonium hydroxide. Other beverages were centrifuged at 4000 rpm for 5 min, and the supernatant was loaded onto the cartridge. The cartridge was washed with water followed by 15% methanol, and the Cinchona alkaloids were eluted with methanol. The Cinchona alkaloids in the eluate were chromatographed on an L-column ODS (4.6 mm id x 150 mm) with methanol and 20 mmol/L potassium dihydrogen phosphate (3 + 7) as the mobile phase. Cinchona alkaloids were monitored with an ultraviolet (UV) detector at 230 nm, and with a fluorescence detector at 405 nm for cinchonine and cinchonidine and 450 nm for quinidine and quinine (excitation at 235 nm). The calibration curves for Cinchona alkaloids with the UV detector showed good linearity in the range of 2-400 microg/mL. The detection limit of each Cinchona alkaloid, taken to be the concentration at which the absorption spectrum could be identified, was 2 microg/mL. The recovery of Cinchona alkaloids added at a level of 100 microg/g to various kinds of beverages was 87.6-96.5%, and the coefficients of variation were less than 3.3%. A number of beverage samples, some labeled to contain bitter substances, were analyzed by the proposed method. Quinine was detected in 2 samples of carbonated beverage.     

高效液相色谱法测定血浆中舒必利浓度

讨论了测定舒必利血药浓度的反相高效液相色谱方法。选用美国Ｂｉｏ－Ｒａｄ７００型高效液相色谱仪,ＲＰ－３１８色谱柱,ＵＶ检测波长２９０ｎｍ,流动相为甲醇－水－冰醋酸（６０３０１）,内标物为胃复安。回收率为９７．９５％～９９．９６％,ＲＳＤ为２．６％～５．１％,最低检出浓度１．０ｍｇ／Ｌ,线性范围５～１００ｍｇ／Ｌ。测定３０例服药病人的血药浓度,得到了满意的结果。     

肝素非还原端饱和结构的紫外吸收研究及在肝素寡糖测序中的应用

为了进一步探讨非还原端饱和结构的肝素寡糖在UV 232 nm的吸收情况, 制备了4种饱和结构的肝素二糖, 并用离子对反相液相色谱/离子阱飞行时间质谱(RPIP-LC/MS-IT-TOF)光电二极管阵列检测器分析了它们在UV 232 nm的吸收情况. 分析结果表明, 饱和结构的肝素二糖在UV 232 nm的检出限为9 μg(S/N=10), UV 232 nm/UV 206 nm约为不饱和结构肝素二糖UV 232 nm的7%~40%. 结果还表明, 肝素二糖UV 232 nm的吸收强度受亚硫酸基团(SO₃^2?)影响较大. 另外, 通过比较不饱和结构的肝素/硫酸类肝素(Hep/HS)标样二糖发现, 含N-未取代葡萄糖胺(GlcNH₃⁺)基团的二糖在UV 232 nm的吸收值较低. 最后, 通过简单的UV检测方法, 结合 HNO₂(pH=4.0)裂解法和RPIP-LC/MS-IT-TOF分析, 简化了含GlcNH₃⁺肝素六糖的测序方法. 本研究为以后用 HNO₂(pH=1.5)裂解法对混合组分N-硫酸化的肝素寡糖结构序列分析提供了可能.     

Simple,quantitative method for low molecular weight dissolved organic matter extracted from natural waters based upon high performance counter-current chromatography

A simple, high-performance counter-current chromatography method with sequential UV absorbance (254 nm) and evaporative light scattering detection (ELSD) was developed for the quantification of pre-extracted low molecular weight dissolved organic matter (DOM) extracted from natural waters. The method requires solid-phase extraction (SPE) extraction of only small volumes of water samples, here using poly(styrenedivinylbenzene)-based extraction cartridges (Varian PPL). The extracted and concentrated DOM was quantified using reversed-phase high-performance counter-current chromatography (HPCCC), with a water/methanol (5:5) mobile phase and hexane/ethyl acetate (3:7) stationary phase. The critical chromatographic parameters were optimised, applying a revolution speed of 1900 rpm and a flow-rate of 1 mL min⁻¹. Under these conditions, 50 μL of extracted DOM solution could be injected and quantified using calibration against a reference natural dissolved material (Suwannee River), based upon UV absorbance at 254 nm and ELSD detection. Both detection methods provided excellent linearity (R² > 0.995) for DOM across the concentration ranges of interest, with limits of detection of 4 μg ml⁻¹ and 7 μg ml⁻¹ for ELSD and UV absorbance, respectively. The method was validated for peak area precision (<5%), and accuracy and recovery based upon spiking seawater samples prior to extraction, together with DOM solutions post-extraction (>95% recovery). The developed method was applied to the determination of the concentration of DOM in seawater, based upon initial sample volumes as small as 20 mL.     

荧光猝灭法测定维生素C片和果汁饮料中抗坏血酸的含量

罗丹明B溶液在激发波长(λex)为365nm时,在发射波长(λem)580nm处有最大荧光发射强度。如向罗丹明B溶液中加入碘溶液(I3-),由于两者之间反应生成缔合物而使其荧光猝灭,但罗丹明B发射荧光的峰位未变。如在此猝灭反应之前加入一定量的抗坏血酸(AA),则上述猝灭作用由于I3^-被AA还原而失效,使荧光得以重现。进一步试验表明,在总体积为50mL中,1×10^-3 mol·L^-1碘溶液为2.0mL,1.0×10^-4 mmol·L^-1罗丹明B溶液为5.00mL,pH 4.7的乙酸-乙酸钠缓冲溶液为5.0mL,在常温下反应10min的条件下,抗坏血酸的浓度在40μmol·L^-1内与其对应的荧光强度之间呈线性关系(注:抗坏血酸反应在碘溶液及罗丹B溶液之前加入),其检出限(3s/k)为5.6×10^-9 mol·L^-1。根据以上事实,提出了应用上述荧光猝灭法间接测定维生素C片剂及注射液中抗坏血酸的含量。分析时取片剂样品5片,研磨混匀后称取25.0mg溶于水中,并定容至250.0mL,取1.00mL溶液按上述方法测定。注射液样品则取0.10mL,加水定容至250.0mL,取1.00mL溶液进行测定。在实际样品基础上进行加标回收试验,测得回收率为97.4%(片剂)和98.4%(注射液),测定值的相对标准偏差(n=6)依次为2.3%,1.7%。还应用此方法测定了3种果汁饮料,所测得结果与用碘量法校对的结果相符。     

HPLC Determination of Trace Hydrazine Levels in Phenelzine Sulfate Drug Substance

Abstract

An HPLC procedure for the estimation of trace hydrazine levels in phenelzine sulfate drug substance has been developed. The hydrazine is derivatized at ambient temperature with salicylaldehyde, and the salazine derivative is measured using short wavelength UV (209 nm). The salazine is separated from unreacted salicylaldehyde and other compounds using a mobile phase consisting of 60:40 acetonitrile-water. The mobile phase was pumped at a flow rate of 1.0 mL/min through a 150 mm × 4.6 mm i.d. reverse phase column (5 μm octadecylsilane, 30% carbon loading). The limit of detection of salazine produced when hydrazine sulfate reacts with salicylaldehyde in an analytical sample was found to be equivalent to 10 ppm of hydrazine (based upon 100 mg of phenelzine sulfate). Absorbance and hydrazine concentration are linear over the range of 10–1000 ppm of hydrazine, with an r² of 0.9998 (n=7) based on peak height. Five samples of phenelzine sulfate analyzed for hydrazine content with salicylaldehyde gave an interassay reproducibility of 2.1%.     

Determination of ambroxol hydrochloride in tablets using flow-injection UV spectrophotometry and HPLC

A flow-injection UV spectrophotometric method was developed for the determination of ambroxol hydrochloride in tablets. The quantitative determination of ambroxol was performed at 245 nm using distilled water as the carrier solvent. In this study, the flow rate, loop volume, and the number of injections per hour were 15 mL/min, 193 μL, and 100, respectively. The analytical signal of ambroxol was linear in the concentration range of 40–200 μg/mL. The detection limit and limit of quantification were found as 11.55 and 38.49 μg/mL, respectively. The results for the determination of ambroxol in tablets, 29.99 ± 0.23 mg (mean ± SD), were in good agreement with the labeled quantities (30 mg/tablet). A relatively high recovery value (100.4%) shows the accuracy of the proposed method. Furthermore, the results obtained were in accordance with those obtained by the HPLC method, which were used as a comparison method for the determination of ambroxol HCl, as far as the Student’s t-test and Fisher test results were concerned. It was concluded that the proposed flow-injection UV spectrophotometric method was fast, accurate, precise, and suitable for automation in the determination of ambroxol. The text was submitted by the authors in English.     

Para-hydroxybenzoic acid as an indirect detection buffer in capillary zone electrophoresis

Summary Para-hydroxybenzoic acid (p-HBA) has been used as indirect UV detection buffer in capillary zone electrophoresis (CZE). Being an UV-absorbing dibasic acid, p-HBA provides both the necessary buffering for pH control over a wide range and UV absorbance for indirect detection. With sodium dodecyl sulfate (SDS) as a probe, a CZE method using p-HBA solution as running buffer was developed to analyze anions, especially ones with low electrophoretic mobilities. The method was used to separate homologous series of sulfonates, SDS in a formulation sample, and SDS in a standard.     

Development and validation of a chiral capillary electrophoresis method for assay and enantiomeric purity control of pramipexole

A rapid method for the enantioseparation of pramipexole and its R‐enantiomer has been developed by capillary electrophoresis. The influence of chemical and instrumental parameters was investigated including the type and concentration of chiral selectors, buffer composition and pH, co‐ions, applied voltage, capillary length and temperature. Optimal separation conditions were obtained using a 50 mM phosphate buffer (pH 2.8) containing 25 mM carboxymethyl‐β‐cyclodextrin on a fused‐silica capillary. Online UV detection was performed at 262 nm. A voltage of 25 kV was applied, and the capillary temperature was kept at 25°C. Hydrodynamic injection was performed at 3.45 kPa for 5.0 s. The separation of enantiomers was achieved in <6.5 min. The method was further validated in terms of stability of solutions, selectivity, linearity (both pramipexole and R‐enantiomer, R²>0.995), LOD and LOQ (0.91 and 2.94 μg/mL, respectively), repeatability (RSD<1.5%) and accuracy (pramipexole, 100.4%; R‐enantiomer, 100.5%). The proposed method was then applied to two kinds of pramipexole dihydrochloride monohydrate commercially available tablets, immediate release tablets (1.50 and 0.125 mg) and sustained release tablets (0.52 mg), to quantify the main component in the tablets. The amount of distomer could be quantified in bulk sample materials.     

Determination of antibacterial flomoxef in serum by capillary electrophoresis

A determination method of flomoxef (FMOX) concentration in serum by capillary electrophoresis is developed. Serum samples are extracted with acetonitrile. After pretreatment, they are separated in a fused-silica capillary tube with a 25 mM borate buffer (pH 10.0) as a running buffer that contains 50mM sodium dodecyl sulfate. The FMOX and acetaminophen (internal standard) are detected by UV absorbance at 200 nm. Linearity (0-200 mg/L) is good, and the minimum limit of detection is 1.0 mg/L (S/N = 3). The relative standard deviations of intra- and interassay variability are 1.60-4.78% and 2.10-3.31%, respectively, and the recovery rate is 84-98%. This method can be used for determination of FMOX concentration in serum.     

Liquid chromatographic determination of carotenoids and vitamins A and E in multivitamin tablets

Carotenoids and vitamins A and E in multivitamin tablets can be determined simultaneously by reversed-phased liquid chromatography (LC) with a programmable UV detector. Samples were dissolved in dimethyl sulfoxide and then extracted with hexane. A portion was injected onto a Symmetry C18, 150 x 4.6 mm id, 5 microns column and chromatographed with a mobile phase of acetonitrile--0.25% ammonium acetate in methanol and 0.05% triethylamine in dichloromethane. A step gradient was used. The system was operated at 25 degrees C with a flow rate of 1.5 mL/min. UV detection was at 325 nm for retinols, 285 nm for tocopherols, and 450 nm for carotenoids. Detection limits were less than 0.3 ng for retinol and retinyl acetate; 2 ng for alpha-tocopherol acid succinate; 10 ng for alpha-tocopherol, gamma-tocopherol, and alpha-tocopherol acetate; and 0.4 ng for alpha-carotene and beta-carotene. Intraday and interday coefficients of variation ranged from 1.40 to 5.20%. The sample preparation method and LC assay are practical for quality control and routine analysis of multivitamin tablets.     

疏水相互作用色谱法分离大豆凝集素

采用疏水相互作用色谱法（ＨＩＣ）,以苯基琼脂糖凝胶ＳｅｐｈａｒｏｓｅＣＬ－４Ｂ为固定相,硫酸铵－磷酸盐缓冲溶液（ｐＨ６．８）为流动相,从大豆匀浆液中分离出大豆凝集素（ＳＢＡ）。     

Identification of allantoin, uric acid, and indoxyl sulfate as biochemical indicators of filth in food packaging by LC.

A liquid chromatographic (LC) method was developed for the determination of allantoin, uric acid, and indoxyl sulfate in mammalian urine contaminated packaging material including paper bagging, corrugated cardboard, grayboard, and burlap bagging. The procedure involves solvent extraction and isolation of the 3 analytes by reversed-phase LC with ultraviolet detection at 225 nm for allantoin and 286 nm for uric acid and indoxyl sulfate. The composition of authentic mammalian urine such as mouse, rat, cat, dog, and human were also determined with regard to the 3 compounds of interest. A linear concentration range of 0.11-20.4, 0.02-10.0, and 0.04-30.0 microg/mL was obtained for allantoin, uric acid, and indoxyl sulfate, respectively. Limits of detection (LOD) and quantitation (LOQ) were 0.0104 and 0.0345 microg/mL for allantoin; 0.0018 and 0.0060 microg/mL for uric acid; and 0.0049 and 0.0165 microg/mL for indoxyl sulfate, respectively. Interday relative standard deviation values for a mixture of standard allantoin, uric acid, and indoxyl sulfate (n = 5) were 0.97, 0.80, and 0.94%, respectively. Analyte composition for 5 types of authentic mammalian urine varied from 0.19-6.88 mg/mL allantoin; 0.08-0.57 mg/mL uric acid; and 0.03-0.78 mg/mL indoxyl sulfate. Analyte content for 8 samples including 2 samples each for paper, cardboard, grayboard, and burlap bagging each contaminated with mouse or rat urine ranged from 相似文献   

Sensitive determination of erythrosine and other red food colorants using capillary electrophoresis with laser-induced fluorescence detection

Capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was applied to separation and sensitive determination of red food colorants. Diode pumped frequency-doubled Nd:YAG laser (532 nm) was used as an excitation source in a laboratory-built CE-LIF system. For highly fluorescent erythrosine B (E127), an extrapolated limit of detection (LOD) of 0.4 ng mL(-1) (S/N=3) was achieved. Extrapolated LODs of other tested red additives, such as carmoisine, E122 (0.5 microg mL(-1)); amaranth, E123 (0.2 microg mL(-1)); ponceau 4R, E124 (0.3 microg mL(-1)) and red 2G, E128 (0.3 microg mL(-1)) were about one-order lower compared to results obtained with CE with absorbance detection in UV/vis (CE-UV/vis). The main advantages of using CE-LIF for analysis of food samples are high selectivity and minimization of matrix effect. To our knowledge, this is the first use of CE-LIF for determination of red food colorants.     

Determination of salbutamol using on-line solid-phase extraction and sequential injection analysis. Comparison of chemiluminescence and fluorescence detection

Determination of salbutamol using sequential injection analysis (SIA) with chemiluminescence and fluorescence detection has been devised. The chemiluminescence signal was emitted during the oxidation of salbutamol by potassium permanganate in sulfuric acid medium. Sodium polyphosphate was used as chemiluminescence enhancer. The fluorescence signal (excitation wavelength 230 nm) was also measured in sulfuric acid medium. Both detection techniques were compared with respect to the application of the methods to the determination of salbutamol in biological materials. The sample pre-treatment takes place directly in the SIA system, when salbutamol is adsorbed on the solid-phase (Baker-carboxylic acid) microcolumn integrated into the system. Sulfuric acid serves both as the reagent and the eluent. The lab-made SIA system consisted of a 2.5-mL Cavro syringe pump, ten-port Vici Valco selection valve and Spectra-Physics FS 970 fluorescence detector, which was lab-modified for chemiluminescence detection. The system was controlled by a PC using originally compiled LabVIEW-supported software. Concentrations, volumes of reagents and flow rates were optimised by a simplex method. Salbutamol was determined in the linear range 0.05-10 microg mL(-1) (RSD 1.53%), with the detection limit (3 sigma) 0.03 microg mL(-1) and sample throughput of 42 samples per hour with chemiluminescence detection in standard solutions. The fluorescence detection enabled the determination of salbutamol in standard solutions in the linear range 0.5-100 microg mL(-1) (RSD 2.69%), with the detection limit 0.2 microg mL(-1) and sample throughput of 24 h(-1). The proposed methods were applied to the determination of salbutamol in human serum and urine. However, serum is a very complicated matrix and the SIA-SPE analysis did not provide satisfactory results. It was possible to determine salbutamol in human urine using this technique. Better recovery was achieved with fluorescence detection.