Validation of a gas chromatographic method for determination of fatty alcohols in 10 mg film-coated tablets of policosanol

A gas chromatographic method using a packed column and 1-eicosanol as an internal standard was validated for the determination of the fatty alcohols that compose policosanol in 10 mg film-coated tablets. The alcohols were determined as trimethylsilyl derivatives, prepared with N-methyl-N-trimethylsilyltrifluoroacetamide. The method can detect degradation products with high retention times, without interfering with the peaks of the active principle. Good linearity (correlation coefficient = 0.9992) and accuracy (mean recovery -100.27 +/- 1.66%) were proven over a range of 25-200% of the nominal concentration. Within- and between-day precision at the nominal 100% value met the acceptance criteria (<2%). Ruggedness was examined through an intralaboratory experimental study in which 6 operational changes were made; the changes were found to have no effect on quantitation, repeatability, resolution, and relative retention time. The method is suitable for the quality control process and stability studies of these tablets.     

Gas chromatographic determination of high molecular weight alcohols from policosanol in omega-3 fish oil by acylation with acetyl chloride

A new validated gas chromatographic (GC) method using acetyl chloride as a derivatizing agent for determining policosanol's high molecular weight alcohols (policosanol's fatty alcohols; PFAs) in fish oil (FO) is described. Before derivatizing the alcohols, FO was subjected to a methylation reaction, and then the PFAs were isolated in a chloroform fraction by silica gel by column liquid chromatography. GC analysis was performed using a BPX-5 wide-bore column and 1-eicosanol as an internal standard. Validation assays applied to the method proved noninterference by a very complex mixture of the FO with PFAs, even for samples subjected to stress conditions. Good linearity [correlation coefficient >0.999, relative standard deviation (RSD) of the slope <1.3%, and RSD of the response factors <1.9% with no bias] and accuracy (average recovery from 100.6 to 102.2%) over a range of 28-142% of the nominal concentration were obtained. Within-day and intermediate precisions at the nominal dose (100%) were 1.7 and 2.9%, respectively. The method was successfully used to identify and quantitate the PFAs in FO.     

Assay of acebutolol in pharmaceuticals by analytical capillary isotachophoresis

Acebutolol [N-{3-acetyl-4-[(2-hydroxy-3-(isopropylamino)propoxy]phenyl} butanamide] is a cardioselective beta-blocker with a potent anti-hypertensive and antiarrhythmic effect. The optimised operational system of electrolytes for the newly developed ITP separation of acebutolol consisted of 10mM potassium acetate +10mM acetic acid (pH 4.65) as the leading electrolyte and 10mM beta-alanine with pH approximately 4 (adjusted with acetic acid) as the terminating electrolyte. The driving and detection currents were 75 and 20 microA, respectively and the analysis took approximately 13 min. Under these conditions the effective mobility of acebutolol was determined as 20.7 x 10(-9) m2 V(-1) s(-1). The calibration dependence was rectilinear in the range 0.14-1.4 mg ml(-1) of acebutolol base (r = 0.9995); relative standard deviation (RSD) values were 1.1% and 1.2% (n = 6) when determining 0.42 and 0.98 mg ml(-1) of acebutolol in a pure standard solution. The method, with the limit of detection (LOD) of 0.04 mg ml(-1) and limit of quantification (LOQ) of 0.12 mg ml(-1), was applied to the assay of acebutolol in Sectral tablets, Acecor tablets, Apo-acebutol tablets (nominal content 400 mg of acebutolol per tablet) and Acebirex tablets (nominal content 200 mg of acebutolol per tablet) with RSD = 0.7-1.7% (n = 6). No interference from any excipients present in the tablets was observed. The recoveries ranged from 98.8% to 102.4% as found by the standard addition technique.     

基于石墨化炭黑预涂覆技术的色谱柱制备和性能评价

采用石墨化炭黑(GCB)预涂覆技术对白酒分析专用色谱柱(LZP-930)的制备方法进行了优化,详细考察了所制备的色谱柱(LZP-930G)的性能参数,并对LZP-930G色谱柱的保留行为进行了评价,探讨了GCB对LZP-930G色谱柱性能的影响。研究发现,LZP-930G色谱柱的柱效、惰性、稳定性和极性均得到了明显提高,从而改善了酸类和醇类组分的分离选择性和色谱峰峰形,实现了白酒中53种易挥发和半挥发性微量组分的同时分离,且各组分的保留时间和峰面积的相对标准偏差分别小于0.63%和4.51%(n=5)。表明GCB预涂覆技术能够用于高性能白酒分析色谱柱的制备方法。     

Determination of low molecular weight alcohols including fusel oil in various samples by diethyl ether extraction and capillary gas chromatography

Low molecular weight alcohols including fusel oil were determined using diethyl ether extraction and capillary gas chromatography. Twelve kinds of alcohols were successfully resolved on the HP-FFAP (polyethylene glycol) capillary column. The diethyl ether extraction method was very useful for the analysis of alcohols in alcoholic beverages and biological samples with excellent cleanliness of the resulting chromatograms and high sensitivity compared to the direct injection method. Calibration graphs for all standard alcohols showed good linearity in the concentration range used, 0.001-2% (w/v) for all alcohols. Salting out effects were significant (p < 0.01) for the low molecular weight alcohols methanol, isopropanol, propanol, 2-butanol, n-butanol and ethanol, but not for the relatively high molecular weight alcohols amyl alcohol, isoamyl alcohol, and heptanol. The coefficients of variation of the relative molar responses were less than 5% for all of the alcohols. The limits of detection and quantitation were 1-5 and 10-60 microg/L for the diethyl ether extraction method, and 10-50 and 100-350 microg/L for the direct injection method, respectively. The retention times and relative retention times of standard alcohols were significantly shifted in the direct injection method when the injection volumes were changed, even with the same analysis conditions, but they were not influenced in the diethyl ether extraction method. The recoveries by the diethyl ether extraction method were greater than 95% for all samples and greater than 97% for biological samples.     

色谱与色谱/质谱法相结合分析热裂解汽油C9馏分

采用毛细管气相色谱-氢火焰离子化检测器（CGC-FID）和气相色谱-质谱法(GC/MS)分析了热裂解汽油C9 馏分的组成。实验使用PONA毛细管气相色谱柱(100 m×0.25 mm i.d.×0.5 μm),根据烃类化合物在PONA柱上的保留规律,以正构烷烃标样保留值作为碳数分布依据,定量分析了裂解汽油C9 馏分中烃类化合物的碳数分布和单体烃含量;用GC/MS联用技术和CGC保留值定性法相结合对裂解汽油C9 馏分中相对含量大于0.2%的39种化合物进行了定性。     

整体柱离子对色谱-间接紫外检测法快速测定N-甲基,丙基吗啉阳离子

建立了快速分析无紫外吸收的N-甲基,丙基吗啉阳离子的离子对色谱-间接紫外检测法。采用反相C18硅胶整体柱,以背景紫外吸收试剂-离子对试剂-有机溶剂为流动相。研究了背景紫外吸收试剂、检测波长、离子对试剂、有机溶剂、柱温、流速对吗啉阳离子测定的影响。最佳色谱条件为:(0.5 mmol/L对氨基苯酚盐酸盐-0.1 mmol/L庚烷磺酸钠)溶液-甲醇(9:1, v/v)为流动相,检测波长230 nm,柱温30 ℃,流速1.0 mL/min。在此条件下,N-甲基,丙基吗啉阳离子的保留时间为2.966 min,检出限为0.07 mg/L(S/N=3),峰面积的相对标准偏差为2.1%(n=5),保留时间的相对标准偏差为0.02%(n=5)。将此方法用于分析实验室合成的N-甲基,丙基吗啉离子液体,加标回收率为98.8%。结果表明本方法简便、快速。     

快速气相色谱法分析白酒中的香味组分

中国的传统白酒里含有多种香味组分,包括醇类、醛类、酸类和酯类,它们的比率决定着白酒的香型和品质。这些组分可以使用气相色谱仪进行很好的分析并定性和定量。为了缩短分析时间,建立了一种快速检测白酒中香味组分的气相色谱法。采用该方法,用20 m×0.1 mm×0.1 μm的熔融石英毛细管柱在12 min之内完成了对白酒中香味组分的分析,分析时间只是传统色谱方法的三分之一。该方法的重现性良好。     

Determination of tetraethyl ammonium by ion-pair chromatography with indirect ultraviolet detection using 4-aminophenol hydrochloride as background ultraviolet absorbing reagent

A method was developed for the determination of tetraethyl ammonium (TEA) by reversed-phase ionpair chromatography with indirect ultraviolet detection. Chromatographic separation was achieved on a reversed-phase C18 column using background ultraviolet absorbing reagent - ion-pair reagent - organic solvent as mobile phase. The effects of the background ultraviolet absorbing reagents, detection wavelength, ion-pair reagents, organic solvents and column temperature on the determination method were investigated and the retention rules discussed. Results found that TEA could be successfully analyzed by using 0.7 μmol/L 4-aminophenol hydrochloride and 0.15 μmol/L 1-heptanesulfonic acid sodium mixed with 20% (v/v) methanol asmobile phase at a UV detection wavelength of 230 nm. Under these conditions, the retention time of tetraethyl ammonium was 2.85 min. The detection limit (S/N = 3) for TEA was 0.06 mg/L. The relative standard deviations (n = 5) for peak area and retention time were 0.35% and 0.02%, respectively. The method has been successfully applied to the determination of synthesized tetraethyl ammonium bromide. Recovery of tetraethyl ammonium after spiking was 99.1%.     

Validation of an HPLC method for the determination of fleroxacin and its photo-degradation products in pharmaceutical forms

HPLC determination of fleroxacin in dosage forms was carried out using either reversed-phase column YMC pack ODS-AQ or Supelco LC Hisep shielded hydrophobic phase column, with UV detection at 280 nm. The mobile phase for ODS column consisted of 50:50:0.5 v/v/v and for Hisep column 15:85:0.5 v/v/v acetonitrile-water-triethylamine. The pH of the mobile phase was adjusted to 6.30 for ODS column and to 6.85 for Hisep column, with H3PO4. Linear response was obtained in the concentration range of fleroxacin between 0.01 and 1.30 micrograms/mL. Detection limit was 4.8 ng/mL. Recovery test in the determination of fleroxacin in "Quinodis" tablets (Hoffmann La Roche, nominal mass 400 or 200 mg) was 98-101% for both columns. The effect of the composition and pH of the mobile phase on spectra, retention time and dissociation constants of fleroxacin was discussed. The proposed method could be also used for separation of the photo-degradation products of fleroxacin. Ten degradation products were separated on the ODS-AQ column, thus confirming the suitability of the proposed method for stability study of fleroxacin in pharmaceuticals.     

六种取代苯的毛细管反相电色谱分离行为的研究

毛细管电色谱（简称ＣＥＣ）是指用电场力驱动的微柱液相色谱［１,２］．目前ＣＥＣ是国际上分离分析技术的研究热点之一,在我们以前的工作中［３］,曾对毛细管电色谱的操作特性进行了研究,证实了ＣＥＣ确是一种高效实用的微分离技术．本文通过考察各种操作条件对不同...     

A selective high-performance liquid chromatography method for the determination of reboxetine in bulk drug and tablets

Reboxetine is used as a selective noradrenaline reuptake inhibitor for the treatment of major depressive disorders. It is effective in the treatment of severe depression and safer to use than traditional tricyclic antidepressants. In this study, a novel, simple, and rapid stability-indicating high-performance liquid chromatography (HPLC) method for reboxetine methansulfonate was successfully developed and validated for the assay of tablets. The method was used to quantify reboxetine in tablets; it employed a C18 column (150 x 4.6 mm id) with an isocratic mobile phase consisting of methanol-phosphate buffer (pH 7, 0.02 M; 55 + 45, v/v) at a flow rate of 1.0 mL/min. Reboxetine was detected by an ultraviolet detector at 277 nm. The retention time of reboxetine was about 4.5 min. The developed HPLC method was validated with respect to linearity, precision, sensitivity, accuracy, and selectivity. The method was linear over the concentration range 1-50 microg/mL (r = 0.9999). The limits of detection and the quantitation of reboxetine were 0.1 and 0.3 microg/mL, respectively. The relative standard deviation values for intraday and interday precision were 0.78-1.01 and 1.08-1.37%, respectively. Selectivity was validated by subjecting a stock solution of reboxetine to neutral, acid, and alkali hydrolysis, as well as oxidation, dry heat treatment, and photodegradation. The peaks of the degradation products did not interfere with the peak of reboxetine. The results indicated that the proposed method could be used in a stability assay. The proposed method was successfully applied to the determination of reboxetine in tablets. Excipients present in the tablets did not interfere with the analysis.     

气相色谱法测定驱蚊功效印刷品中3种功效化合物

建立了气相色谱–氢火焰离子技术测定功效印刷品中3种驱蚊成分的方法。样品用二氯甲烷进行超声提取,邻苯二甲酸二丁酯为内标,利用毛细管色谱柱HP–5(30 m×0.32 mm,0.25μm)分离,保留时间定性,内标法定量。结果表明,3种驱蚊功效物质色谱分离良好,在质量浓度0.1~1.0 mg/L范围内与色谱峰面积呈线性相关。方法定量限(10S/N)为1.25 mg/kg,样品加标回收率为97%~108%,测定结果的相对标准偏差不大于8.1%(n=6)。该方法快速、可靠、准确、简便,适用于驱蚊功效的印刷品中3种驱蚊功效类化合物的分析检测。     

反相高效液相色谱中流动相线性梯度洗脱条件下溶质保留时间预测的新方法

 在计算溶质的梯度保留时间时 ,根据流动相在色谱柱内的分布规律 ,对溶质在色谱柱内的迁移距离和流动相梯度同时进行校正 ,从而建立了一种预测溶质线性梯度洗脱条件下保留时间的新方法。该方法在不同的仪器系统中 ,对于弱保留和强保留溶质在不同线性梯度洗脱条件下保留时间的预测 ,都具有良好的准确度。以 15种氨基酸和 8种苯的同系物为例 ,该方法对于弱保留溶质保留时间的预测 ,相对平均误差分别为 3 70 %和 4 90 % ,远小于文献方法得到的结果 (2 3 6 1%和 31 16 % ) ;对于强保留溶质保留时间的预测 ,相对平均误差分别为 0 2 1%和6 0 1% ,略小于文献 。     

Separation Performance of MOFs Zn(ISN)2·2H2O as Stationary Phase for High-Resolution GC

Metal–organic frameworks (MOFs) as a new type of porous materials have attracted tremendous attention for their potential applications in recent years. Here, we used a simple chiral MOF, Zn(ISN)₂·2H₂O, as chiral stationary phase for high-resolution gas chromatography. A Zn(ISN)₂·2H₂O-coated fused-silica capillary column (3 m long × 75 μm i.d.) was fabricated by using a dynamic coating method with ethanol suspension of Zn(ISN)₂·2H₂O (1 mg mL^?1). Then, the coating properties, polarity, and column efficiency of the column were studied. The column efficiency of Zn(ISN)₂·2H₂O-coated column was up to 3,020 plates m^?1. The separation performance was investigated by separating a wide range of organic compounds such as Grob test mixtures, alkanes, alcohols, isomers, and racemates. The relative standard deviations for the five replicate separations of alanine were 0.32 and 2.6 % for retention time and peak area, respectively. The experimental results showed that the new stationary phase possesses high column efficiency, good reproducibility, excellent selectivity, and chiral recognition ability.     

Separation Performance of MOFs Zn(ISN)2·2H2O as Stationary Phase for High-Resolution GC

Metal–organic frameworks (MOFs) as a new type of porous materials have attracted tremendous attention for their potential applications in recent years. Here, we used a simple chiral MOF, Zn(ISN)₂·2H₂O, as chiral stationary phase for high-resolution gas chromatography. A Zn(ISN)₂·2H₂O-coated fused-silica capillary column (3 m long × 75 μm i.d.) was fabricated by using a dynamic coating method with ethanol suspension of Zn(ISN)₂·2H₂O (1 mg mL⁻¹⁾. Then, the coating properties, polarity, and column efficiency of the column were studied. The column efficiency of Zn(ISN)₂·2H₂O-coated column was up to 3,020 plates m⁻¹. The separation performance was investigated by separating a wide range of organic compounds such as Grob test mixtures, alkanes, alcohols, isomers, and racemates. The relative standard deviations for the five replicate separations of alanine were 0.32 and 2.6 % for retention time and peak area, respectively. The experimental results showed that the new stationary phase possesses high column efficiency, good reproducibility, excellent selectivity, and chiral recognition ability.

     

Determination of alcohols by high-performance liquid chromatography with fluorimetric detection after pre-column derivatisation with carbazole-9-N-acetic acid and chromatographic behaviour of alcoholic derivatives

Alcohols were derivatised to their carbazole-9-N-acetic acid (CRA) esters with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC.HCl) as the dehydrating agent. Studies on derivatisation conditions indicated that the coupling reaction proceeded rapidly and smoothly in the presence of a base catalyst in acetonitrile to give the corresponding sensitively fluorescent derivatives. The retention behaviour of alcohol derivatives was investigated by varying mobile phase compositions (ACN-water and MeOH-water). The parameters from the equation log k'=A-BX were evaluated by retention data of derivatives using an isocratic elution with different mobile phases. The results indicated that the parameters derived allowed computation of retention factors in good agreement with experiments. At the same time, a general equation was derived that makes possible predictions of partition coefficient in binary mobile phases with different proportions of organic solvent to water based on some simple regression analysis. The LC separation for the derivatised alcohols containing higher carbon alcohols showed good reproducibility on a reversed-phase C18 column with gradient elution. The detection limits (excitation at 335 nm, emission at 360 nm) for derivatised alcohols (signal-to-noise ratio=3:1) were in the range of 0.1-0.4 pg per injection.     

3D Chiral Nanoporous Metal–Organic Framework for Chromatographic Separation in GC

Metal–organic frameworks (MOFs) have received great attention as stationary phases in chromatographic separation technology because of their unusual properties such as high surface areas, fascinating structures, and excellent chemical and thermal stability. A chiral MOF, [(CH₃)₂NH₂][Cd(bpdc)_1.5]·2DMA, possesses a unique chiral nanotube motif built from the covalent linkage of homochiral nanotubes made up of octuple helices. Here, we report the fabrication of a three-dimensional (3D) chiral nanoporous MOF-coated capillary column (2 m long × 75 μm i.d.) for capillary gas chromatographic separation of racemates, Grob’s test mixture, normal alkanes, normal alcohols, and isomers. The MOF-coated capillary column offered good separation efficiency (2,180 plates m^?1), which was measured using n-dodecane as the analyte at 120 °C. The relative standard deviations of repeatability for citronellal on MOF-coated capillary column were 0.23 and 2.1 % for retention time and peak area, respectively. The results demonstrated that the capillary column exhibited excellent selectivity and separation ability toward Grob’s test mixture, normal alkanes, normal alcohols and isomers, especially for racemates.     

Enantioseparation by HPLC Using an Inorganic Chiral Mesoporous Silica with Highly-ordered Structure

Highly-ordered inorganic chiral mesoporous silica(HOCMS) has attracted substantial interest in recent decades. High performance liquid chromatography(HPLC) is the most important approach for the separation of enantiomers and herein reported an HPLC chiral stationary phase composed of HOCMS. The column was fabricated by conventional high pressure slurry packing. Eighteen racemates, including alcohols, ketones, amines, aldehydes and organic acids, were resolved on the column. Good chiral separations of hydrobenzoin, metoprolol, propranolol hydrochloride, 4-methyl-2-pentanol, omeprazole, 2,2'-furoin and ketoprofen were obtained. The relative standard deviations for five replicate separations of racemates were 0.1%-0.16% for retention time and 1.73%-2.64% for peak areas. The results suggest that HOCMS is a promising candidate for preparation of chiral stationary phases for HPLC.     

Gas chromatographic determination of guanidino compounds in uremic patients using glyoxal as derivatizing reagent

The guanidino compounds guanidine, methylguanidine, guanidinoacetic acid, guanidinopropionic acid, guanidinobutyric acid and guanidinosuccinic acid were eluted and separated after pre-column derivatization with glyoxal from an HP-5 column (30 m × 0.32 mm i.d.) with film thickness 0.25 μm at an initial column temperature of 100 °C for 2 min, with ramping of 20°C/min up to 250 °C and a nitrogen flow rate of 3 mL/min. Detection was by flame ionization detection. Linear calibrations were observed within 0.1-20.0 μmol/L, with limit of detection within 0.024-0.034 μmol/L for each compound. The separation was repeatable with relative standard deviation (RSD) (n = 6) within 1.2-1.8 and 1.1-1.6% in terms of retention time and peak height/peak area, respectively. The method was applied for the determination of the guanidino compounds from serum of uremic patients (n = 7) and healthy volunteers (n = 8), and amounts were observed within 1.33-11.71 and 0.07-0.39 μmol/L with RSD 1.1-3.5 and 1.1-3.0%, respectively. The results were further supported by the standard addition method.