Determination Of Ephedrine Research Articles

Ephedrine Analysis in Real Urine Sample via Solvent Bar Microextraction Technique Coupled with HPLC-UV and Chemometrics

Background: Ephedrine, an alpha/beta-adrenergic agonist, is one of the most common doping agents not only among athletes but also the ordinary people, therefore its detection at low trace levels with a sensitive and cost effective method has become a priority to investigate many analytical methods. Objective: In this work, solvent bar microextraction followed by high-performance liquid chromatography (HPLC-UV) was used for extraction and determination of ephedrine at low trace levels from urine samples at optimum condition. Methods: In this study, a designed experiment was carried out using solvent bar microextraction technique, which has been proved to be a green method. This method requires three phases consisting of a donor phase with an alkaline pH, an acceptor phase with an acidic pH, and organic solvent to impregnate the pores of the hollow fiber. The obtained results were used for estimating the optimum ranges for each parameter, analyzing the effect of different parameters, simultaneously. Results: Under optimized circumstances, the preconcentration factor was 129. The calibration curves represented good linearity for urine sample with coefficient estimations higher than 0.9991. The limit of detection and quantitation for ephedrine were 16.7 µg L-1 and 50 µg L-1, respectively. The relative standard deviations of analysis were 3.5% within a day (n=3) and 4.1% between days (n=9). Conclusion: According to the results and previous studies, it can be concluded that the preconcentration factor for ephedrine was the best result ever reported considering selectivity and cost-effectiveness.

Micellar liquid chromatographic method for the determination of ephedrine and pseudoephedrine in human serum by direct inject of the sample with simple dilution

ABSTRACTA micellar high-performance liquid chromatographic method was developed to simultaneously determine ephedrine and pseudoephedrine in human serum. The serum sample pretreatment was a simple dilution in a micellar solution, filtration, and direct injection, thus avoiding time-consuming and tedious steps. Hence, there is no need to use an internal standard. The serum samples were analyzed using a mobile phase containing 1.50 × 10−1 mol/L sodium dodecyl sulfate and 0.02 mol/L sodium dihydrogen phosphate with 7.5% (v/v) 1-propanol at pH 3.0, running at 1.0 mL/min by an Inertsil C18 (150 × 4.6 mm, 5 µm) column at 30°C. The UV wavelength was set at 210 nm. The developed method was validated by linearity (r > 0.9990) and intra- and inter-day precisions of ephedrine and pseudoephedrine (relative standard deviation; RSD%, 0.04–10.40, and RSD %, 0.30–10.25, respectively), LODs for ephedrine and for pseudoephedrine was 2.63 and 2.70 µg/mL, respectively; lower limit of quantification for ephedrine and for pseudoephedrine was 4.38 and 4.51 µg/mL, respectively. Finally, the proposed method was applied to investigate ephedrine and pseudoephedrine in real human serum samples after oral administration of Kechuanning Koufye including Ephedra herb. It is environmentally friendly, easy-to-handle, and feasible method for routine analysis in clinical laboratory.

Determination of Ephedrine and Pseudoephedrine by Field-Amplified Sample Injection Capillary Electrophoresis

A simple and rapid capillary electrophoresis method was developed for the separation and determination of ephedrine (E) and pseudoephedrine (PE) in a buffer solution containing 80 mM of NaH2PO4 (pH 3.0), 15 mM of β-cyclodextrin and 0.3% of hydroxypropyl methylcellulose. The field-amplified sample injection (FASI) technique was applied to the online concentration of the alkaloids. With FASI in the presence of a low conductivity solvent plug (water), an approximately 1,000-fold improvement in sensitivity was achieved without any loss of separation efficiency when compared to conventional sample injection. Under these optimized conditions, a baseline separation of the two analytes was achieved within 16 min and the detection limits for E and PE were 0.7 and 0.6 µg/L, respectively. Without expensive instruments or labeling of the compounds, the limits of detection for E and PE obtained by the proposed method are comparable with (or even lower than) those obtained by capillary electrophoresis laser-induced fluorescence, liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. The method was validated in terms of precision, linearity and accuracy, and successfully applied for the determination of the two alkaloids in Ephedra herbs.

Simultaneous determination of ephedrine and N -methylephedrine in urine by solid phase extraction-ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry

A rapid and sensitive method has been developed for the simultaneous determination of ephedrine and N-methylephedrine in urine samples by solid phase extraction-ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (SPE-UPLC-ESI MS/MS). The samples were extracted with Oasis MCX solid phase extraction cartridges and measured in the modes of electrospray positive ionization (ESI +) and multiple reaction monitoring (MRM). Good linearities were observed in the range of 0.025 0 - 2.50 microg/L with correlation coefficient over 0.999 0 for both analytes. The recoveries were above 80% with RSDs less than 5.0%. The limits of detection were 0.01 microg/L. The method proves to be rapid and sensitive for the trace determination of ephedrine and N-methylephedrine in urine samples.

A novel cross-H-channel interface for flow injection-capillary electrophoresis to reduce sample requirement and improve sensitivity

In this study, a cross-H-channel interface was constructed for coupling flow injection with capillary electrophoresis (FI-CE) to reduce sample requirement and sensitivity loss in the typical FI-CE. Based on this cross-H-channel interface, a new FI-CE system was established, in which sample introduction was performed by directly injecting sample solution along a thin capillary (50 μm, i.d.) to the interface from an injection syringe. The sample requirement was reduced distinctly and usual sample dilution in the sample transport process was obviously decreased, thereby spontaneously enhancing the sensitivity. Moreover, because of the unique construction of the cross-H-channel interface, field amplified sample stacking (FASS) and high-speed CE were skillfully combined to further improve the sensitivity and to shorten separation time. The versatility of this new FI-CE was demonstrated by determination of ephedrine (E) and pseudoephedrine (PE) in human urine. Up to 45 repeated injections per hour and clearly baseline separation of E and PE in less than 1 min were achieved, giving limits of detection (LODs) of 0.23 and 0.21 μg mL(-1) for E and PE, respectively, and yielding relative standard deviation (RSD) values of the migration time and the peak height (n=5) of 2.6% and 3.1% for E, 2.3% and 3.3% for PE, respectively. In contrast to typical FI-CE, approximately 8-250-fold decreases in sample volume requirement, 7-fold shortening in separation time and 50-fold improvements in sensitivity were obtained.

Determination of diastereoisomeric alkaloids in urine by capillary electrophoresis with electrochemiluminescence detection

Abstract A new and simple capillary electrophoresis with electrochemiluminescence detection was developed for the separation and the quantification of a pair of diastereoisomeric alkaloids (ephedrine and pseudoephedrine). The limits of detection (S/N = 3) were 4.5 × 10 −8 mol/L for ephedrine and 5.2 × 10 −8 mol/L for pseudoephedrine, respectively. The RSDs of migration time and peak area were less than 1.3 and 2.5% ( n = 5), respectively. The applicability of the propose method was illustrated in the determination of ephedrine and pseudoephedrine in human urine, ephedrine in nasal drops, and the monitoring of pharmacokinetics for pseudoephedrine.

Determination of Ephedrine, Pseudo-Ephedrine and Caffeine in a Dietary Product by Capillary Electrophoresis

This paper reports the determination of caffeine, ephedrine and pseudo-ephedrine in a dietary product by two rapid and simple methods utilising capillary electrophoresis (CE). The solutes were extracted from the product using 0.2 M HCl and determined by CE with background electrolytes containing 7.5% highly sulfated-β-cyclodextrin (7–11 sulfate groups per β-CD molecule) at pH 2.5 and pH 7.6. Determination of ephedrine and pseudo-ephedrine was accomplished at pH 2.5 with the anode at the detection side of the capillary whereas caffeine was quantified at pH 7.6 with a normal electrophoresis polarity mode. Triethanolamine was added to the running buffer at pH 2.5 in order to reverse the electroosmotic flow (EOF) and thereby speed up the separation of ephedrine and pseudo-ephedrine.

A systematic approach to quantitation of ephedra alkaloids in natural health products

A method for accurate determination of ephedrine (E) alkaloids in natural health products (NHP) is described. The NIST dietary supplement standard reference materials (SRMs) were selected for these studies. These SRMs comprise ground Ma Huang herb (Ephedra sinica Stapf.), a spray dried extract of the former, and commercial formulations derived from gel caps and a protein drink. The efficiency of sonication-assisted extraction and Soxhlet extraction was studied using both ammonium formate and potassium phosphate in 3% methanol as extraction media. The efficiency of SPE clean-up of the extract deteriorated rapidly when increasing amounts of sample matrix or analyte were processed, because of limited cartridge capacity. Quantitation by the method of additions was required to ensure the highest accuracy using both LC-UV and ES-LC-MS-MS techniques. Whereas the LC-UV method is more convenient and precise, the results are more questionable than ES-LC-MS-MS, because species-specific detection is not possible.

Rapid and sensitive determination of ephedrine and pseudoephedrine by micellar electrokinetic chromatography with on-line regenerating covalent coating.

A rapid, sensitive and reproducible micellar electrokinetic chromatographic method using hexamethyldisilazane as on-line regenerating covalent coating was developed for the quantification of ephedrine (E) and pseudoephedrine (PE). E and PE were derivatized with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazol for laser-induced fluorescence detection. The on-line regenerating covalent coating formed a combinative double coating with the subsequently produced dynamic SDS coating. The total coating can be easily removed and conveniently regenerated on-line. The simple coating procedure was described. By a series of optimization, a running buffer of 20 mm Na(2)B(4)O(7) + 16 mm SDS was applied for the separation of the derivatives. Linear relationships for E and PE were obtained in the range of 0.044-6.60 microg mL(-1) (correlation coefficients: 0.9975 for E, 0.9981 for PE), and the detection limits for E and PE were 1.71 and 0.67 ng mL(-1), respectively. The separation speed, the reproducibility and the sensitivity were much improved over those of other capillary electrophoresis methods more recently reported. The method was applied to the analysis of the two alkaloids in traditional herbal preparations with recoveries in the range 92.8-104.8%.

Micellar electrokinetic chromatography with laser‐induced fluorescence detection for sensitive determination of ephedrine and pseudoephedrine

A selective and sensitive micellar electrokinetic chromatography method with laser-induced fluorescence detection was developed for the quantification of ephedrine (E) and pseudoephedrine (PE) derivatized with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole. After conducting a series of optimizations, a running buffer of 10 mM sodium borate + 16 mM SDS was used for separation of the derivatives. A linear relationship for E and PE was obtained in the range of 0.044-6.6 microg mL(-1) (correlation coefficient: 0.9943 for E, 0.9946 for PE), and the detection limits for E and PE were 0.70 and 0.30 ng mL(-1), respectively. The sensitivity of E and PE was improved by several multiples of ten over those of CZE-LIF method. The method was applied to the analysis of the two alkaloids in ephedra herbal medicine and preparations with recoveries in the range of 98.3-107.1%.

Determination of ephedrine in compound furaclin and ephedrine nasal drops by ultraviolet spectrophotometry

目的 建立呋麻滴鼻液中盐酸麻黄碱的紫外分光光度法的含量测定方法.方法次氯酸钠为氧化剂,测定由盐酸麻黄碱被次氯酸钠氧化后的氧化产物苯甲醛,检测波长为249 nm.结果盐酸麻黄碱在2～18μg/ml范围内,线性关系良好(r=0.9996),平均回收率为98.05%(n=9,RSD=0.72%).结论本法灵敏度高,快捷准确。

Composition and stability of complexes of Ephedrine hydrochloride with Ni2+, Zn2+, and Cd2+ as toxic ions

The complexes of Ephedrine with Nickel, Zinc and Cadmium ions have been investigated spectrophotometricalfy using the method of corresponding solutions [I-3] and pH-metrically using Irving and Rossoti technique [4] Two compositions were observed spectrophotometrically 1 : 1 and 2: 1 (L: M) for concentration of metal ions (0.5 x 10-3 M and 1 x 10-3 M) hile the first composition only predominate at concentration of metal ions (1.5 x 10-3 M and 2 x 10-3 M ). The stability of complexes show that complexes of Ni2+ are more stable than that of Zn2+ an Cd2+, Moreover, the composition and stabilities of complexes were studied pHmetrically in aqueous medium at 0.1 M NaCl and two different temperatures 30°C and 40°C; hence the value of the free energy change (ΔG°), the enthalpy (ΔH°) and the entropy (ΔS°) were calculated at 30°C. Beside the role of Ephedrine as chelating agent to toxic elements, the complexometric method was used for the determination of Ephedrine in its pure form and in tablets.

Separation and determination of ephedrine and pseudoephedrine by combination of flow injection with capillary electrophoresis.

A simple, rapid, and accurate method for the separation and determination of ephedrine and pseudoephedrine using direct UV absorbance detection has been developed by the combination of flow injection with capillary electrophoresis for the first time. The buffer solution used is a 40 mM borate solution with the pH adjusted to 9.5 using a 2 M NaOH solution. The linear calibration range is 50 to 1000 microg/mL (r = 0.9996) for both analytes, and the recoveries are 91.2-108.2% for ephedrine and 92.6-107.3% for pseudoephedrine, respectively. The relative standard deviation of the peak area is 1.6% for ephedrine and 1.3% for pseudoephedrine (n = 6) at a concentration of 500 microg/mL, respectively. A series of samples is injected repeatedly without current interruption and subsequent rinsing, and the contents of these two alkaloids in three marketed drugs and the medical plant, Ephedra sinica, are determined with satisfactory results by this method.

DETERMINATION OF EPHEDRINE, GASTRODIN, AND LIGUSTRAZIN IN SPIKED RAT PLASMA BY CAPILLARY MICELLAR ELECTROKINETIC CHROMATOGRAPHY

A simple and rapid capillary micellar electrokinetic chromatography (MEKC) method was developed for the separation and determination of ephedrine, gastrodin and ligustrazin in tetraborate buffer by direct UV detection at 200 nm. The effect of separation voltage, the concentration of sodium dodecyl sulfate (SDS) and the buffer pH value on separation was optimized and the following conditions was selected: 20 kV voltage, 15 mM SDS in 50 mM tetraborate buffer at pH = 9.50. The detection limit of these substances was below 1.0 μg/mL, respectively, and the linear range spanned two orders of magnitude. This method was applied to the detection of ephedrine, gastrodin and ligustrazin spiked in rat plasma.

Determination of ephedrines in urine by gas chromatography–mass spectrometry

A selective gas–liquid chromatographic method with mass spectrometry (GC–MS) for the simultaneous confirmation and quantification of ephedrine, pseudo-ephedrine, nor-ephedrine, nor-pseudoephedrine, which are pairs of diastereoisomeric sympathomimetic amines, and methyl-ephedrine was developed for doping control analysis in urine samples. O-Trimethylsilylated and N-mono-trifluoroacetylated derivatives of ephedrines — one derivative was formed for each ephedrine — were prepared and analyzed by GC–MS, after alkaline extraction of urine and evaporation of the organic phase, using d 3-ephedrine as internal standard. Calibration curves, with r 2>0.98, ranged from 3.0 to 50 μg/ml depending on the analyte. Validation data (specificity, % RSD, accuracy, and recovery) are also presented.

Determination of ephedrine, theophylline and phenobarbital in a tablet dosage form by capillary electrophoresis

A capillary electrophoresis method was developed to separate and quantitate ephedrine (ED), theophylline (TP) and phenobarbital (PB) in a tablet dosage form. Tablets were ground and extracted with methanol using ultrasonication. Aliquots of standard stock solution were hydrodynamically injected for 5 s at the anodic end. Separation was performed on a fused silica capillary (72 cm×50 μm i.d.; 50 cm to detector) at an applied voltage of 20 kV with a phosphate run buffer (pH 8.0, 50 mM). Analysis was performed at ambient temperature (23±1°C) and the total run time was 9 min with detection at 220 nm. Calibration curves were prepared for ED, TP and PB with methyl p-hydroxy benzoate as internal standard. For each analyte, the correlation coefficients were >0.999 ( n=4). The RSD% of ten replicate injections for each analyte were <1%. The method was applied to the quantitation of ED, TP and PB in a commercial tablet dosage form.

Potentiometric and Optical Measurements for the Determination of Ephedrine

A PVC membrane electrode based on the ephedrine reineckate ion pair was constructed. Small ion pair percentages (0.1–5% w/w) were tested successfully giving Nernstian behavior. The slope of the calibration graph was 56 mV/decade for the 5% ion pair. The optimum working pH range of the electrode is 4.0–9.0. The linear usable concentration range is 2 × 10−6to 10−1M ephedrine. The suitable selectivity of the electrode toward ephedrine relative to other cations, amines, sugars, and some pharmaceuticals was recorded. The potential drift of the electrode did not exceed 0.58 mV/day. The effect of temperature on electrode performance was studied in the range of 25–95°C and it worked with Nernstian behavior up to 85°C. Electrode performance is compared with that of previously reported electrodes. The determination of ephedrine in its pharmaceutical preparations was performed with a mean recovery of 98.7% and average relative standard deviation of 1.9%. Application of the membrane to optical measurements for ephedrine was attempted at different pH values.

Analysis of Antihistamines in Cough Syrup

An efficient and simple high performance liquid chromatography method was developed for determination of Ephedrine. Noscapine, Promethazine and Bromhexine in cough syrup. Cough syrup samples could be cleaned up by anionic exchange solid phase extraction disk. The method has been validated with good recovery, linearity, reproducibility and selectivity for simultaneous determination of common antihistamines in over-the-counter cough syrup mixtures.

Hair analysis for drugs of abuse XIX. Determination of ephedrine and its homologs in rat hair and human hair

A sensitive GC-MS method was developed for the quantitative analysis of ephedrine (EP), phenylpropanolamine (PPA) and methylephedrine (ME) in animal and human hair. After washing with 0.1% sodium dodecyl sulfate, hair samples (10 mg) were added with deuterated internal standards, extracted by 1-h sonication and over night soaking in 2 ml of 5 M HCl-methanol (1:20) at room temperature. Following evaporation of the liquid phase, the residue was dissolved in phosphate buffer solution (pH 6.0) and purified using a solid-phase extraction procedure with Bond Elut Certify columns. Two types of derivatization were compared - using trifluoroacetic anhydride (TFAA) and pentafluoropropionic anhydride (PFPA) - for discrimination of EP and methamphetamine (MA). Derivatized extracts were analyzed by GC-MS in the EI mode using a capillary column (OV-1 equivalent). From the results comparing three GC-MS conditions, PFP-derivatives separated with a temperature gradient of 20°C/min from 60°C to 280°C gave the best resolution between EP and MA. ME was analyzed as a trimethylsilyl derivative using N, O-bis-trimethylsilyl acetamide at the above GC condition. The assay was linear from 0.5 to 50 ng/mg ( r=0.998) and capable of detecting less than 50 pg of derivatized EP, PPA and ME on-column. Intra-assay precision was characterized by C.V. values from 5 to 16% in the concentration range of 1–10 ng/mg hair. The method was used for the quantitative determination of EP, PPA and ME in the hair obtained from three rats with dark brown hair after ten intraperitoneal injections (5 mg/kg/day) of the three drugs and from three male and one female volunteers with black hair after an oral dose of 50 mg/day of EP-HCl for three days. Hair samples were collected by shaving from the back of rats and cutting from the scalp of humans 28 days after the first dose. The incorporation rates of EP, PPA and ME into hair (the ratios of [hair concentration] to [AUC]) obtained from the animal experiment were 0.10, 0.07 and 0.03, respectively, which are a little lower than those (0.14, 0.10 and 0.04) of their desoxy-compounds, MA, amphetamine and dimethylamphetamine. EP was detected at an average of 2.25 ng/mg ( n=4) in human scalp hair and at a range of 1–29 ng/mg ( n=3) in human beard hair until day 14, but its metabolite (PPA) was at a trace level in the hair of the four subjects. The method was successfully used for detection of ME and EP in the hair of a neonate and its mother who was abusing Bron syrup containing ME during the pregnancy.

Effect of using mixed ion-pairs on PVC-membrane electrodes for ephedrine

Mixed ion-pairs based on the use of ephedrinium (EPH)-TPB plus EPH-reineckate (II) and phenylephrine-TPB plus EPH-reineckate (III) were tried for use in plastic membranes. The results were compared to those of an EPH-reineckate (I) single ion-pair electrode. The Nernstian slopes were 50, 49 and 55 mV decade−1 for membranes I, II and III, respectively. The linear concentration ranges were 10−5−10−1, 4.0 × 10−5−10−1 and 6.3 ×−5−10−1M ephedrine. The detection limits were 4 ×−6,10−5 and 1.2 × 10−5M ephedrine for membranes I, II and III, respectively. The pH ranges were 4−9, 3−9 and 2−8 for I, II and III-membranes, respectively. Selectivity coefficient values for membrane II were better than those for membranes I and III. The effects of increasing KC1 concentration and temperature changes were explained for the three electrodes. The isothermal temperature coefficients were 0.00145, 0.0007 and 0.00055 V/ °C for electrodes I, II and III. Electrode III was applied for the determination of ephedrine in its pharmeaceutical preparations with an overall relative standard deviation range of 1.3–2.4% and an overall mean recovery value of 98.1%.