Determination of enrofloxacin and its metabolite ciprofloxacin in goat milk by high-performance liquid chromatography with diode-array detection. Optimization and validation

A high-performance liquid chromatography-diode array detection method (HPLC-DAD) combined with liquid chromatography-mass spectrometry was developed for the determination of enrofloxacin and its metabolite ciprofloxacin in goat milk. The HPLC-DAD method validation was compliant with the "DG SANCO 1805/2000" European regulation. The residues were extracted from milk with phosphate buffer, purified on a C18 Speedisk cartridge SPE (Baker) and then analysed using HPLC-DAD set at 277 nm. The decision limit (CCa) calculated by spiking samples at 100 microg/kg with both analytes, taking into account the maximum residue limit (MRL) of 100 microg/kg established by the European Union for the sum of enrofloxacin and its metabolite ciprofloxacin in milk, was 105.3 microg/kg for enrofloxacin and 105.5 microg/kg for ciprofloxacin. The detection capability (CCbeta) was 110.7 and 110.9 microg/kg for enrofloxacin and ciprofloxacin, respectively. The mean recoveries of the method, calculated by spiking samples at 50, 100 and 150 microg/kg were 84% for enrofloxacin and 88% for ciprofloxacin. The limit of quantification was 20 microg/kg for both analytes. The HPLC-DAD validated method was successfully applied for the first time in goats milk, and proved to be suitable for the sensitive and accurate quantification and confirmation analysis of enrofloxacin and ciprofloxacin for regulatory purposes.     

A UPLC‐MS/MS method for simultaneous quantitation of three monoterpene glycosides and four alkaloids in rat plasma: application to a comparative pharmacokinetic study of Huo Luo Xiao Ling Dan and single herb extract

The objective of this study was to develop a sensitive and reliable ultra performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS) method for simultaneous quantitation of three monoterpene glycosides (paeoniflorin, alibiflorin and oxypaeoniflorin) and four alkaloids (tetrahydropalmatine, corydaline, dehydrocorydaline and berberine), the main active ingredients of Radix Paeoniae Rubra extract (RPE) and Corydalis yanhusuo extract (CYE) in Huo Luo Xiao Ling Dan (HLXLD), and to compare the pharmacokinetics of these active ingredients in normal and arthritic rats orally administrated with HLXLD or RPE/CYE alone. The analytes and internal standard (IS) (geniposide) were separated on a XBridge C₁₈ column (150 × 4.6 mm, 3.5 µm) using gradient elution with the mobile phase consisting of methanol and 0.01% formic acid in water at a flow rate of 0.6 ml/min. The detection of the analytes was performed on Acquity UPLC‐MS/MS system with an electrospray ionization and multiple reaction monitoring mode via polarity switching between negative (for monoterpene glycosides) and positive (for alkaloids) ionization mode. The lower limits of quantification were 2.5, 1, 0.5, 0.2, 0.2, 0.02 and 0.01 ng/ml for paeoniflorin, alibiflorin, oxypaeoniflorin, tetrahydropalmatine, corydaline, dehydrocorydaline and berberine, respectively. Intra‐day and inter‐day precision and accuracy of analytes were well within acceptance criteria (15%). The mean extraction recoveries of analytes and IS from rat plasma were all more than 83.1%. The validated method has been successfully applied to determination of the analytes. Results showed that there were remarkable differences in pharmacokinetic properties of the analytes between herbal formula and single herb group, normal and arthritic group. Copyright © 2015 John Wiley & Sons, Ltd.     

Determination of cadmium, chromium, copper and lead in sediments and soil samples by electrothermal atomic absorption spectrometry using zirconium containing chemical modifiers.

A method for direct determination of cadmium, chromium, copper and lead in sediments and soil samples by electrothermal atomic absorption spectrometry using Zr, Ir, etylenediamine acetic acid (EDTA), Zr + EDTA, Ir + EDTA, Zr + Ir and Zr + Ir + EDTA as chemical modifiers in 0.5% (v/v) Triton X-100 plus 0.2% (v/v) nitric acid mixture used as diluent was developed. The effects of mass and mass ratio of modifiers on analytes in sample solutions were studied. The optimum masses and mass ratios of modifiers: 20 microg of Zr, 4 microg of Ir, 100 microg of EDTA and 20 microg of Zr + 4 microg of Ir + 100 microg of EDTA, were used to enhance the analyte signals. Pyrolysis and atomization temperatures, atomization and background absorption profiles, characteristic masses, and detection limits of analytes in samples were compared in the presence or absence of a modifier. The detection limits and characteristic masses of analytes in a 0.5% (m/v) dissolved sample (dilution factor of 200 ml g(-1)) obtained with Zr + Ir + EDTA are 8.0 ng g(-1) and 1.2 pg for Cd, 61 ng g(-1) and 4.3 pg for Cr, 32 ng g(-1) and 23 pg for Cu, and 3.4 ng g(-1) and 19 pg for Pb, respectively. The Zr + Ir + EDTA modifier mixture was found to be preferable for the determination of analytes in sediment and soil-certified and standard reference materials. Depending on the sample type, the percent recoveries of analytes were increased from 81 to 103% by using the proposed modifier mixture; the results obtained are in good agreement with the certified values.     

Monitoring of priority pesticides and other organic pollutants in river water from portugal by gas chromatography-mass spectrometry and liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) were optimized and applied for the trace-level determination of 42 priority pesticides and 33 priority organic pollutants from European Union Directive EC 76/464. First, off-line solid-phase extraction of 200 ml of river water using an OASIS solid-phase extraction cartridge, followed by GC-MS was used. Next, selected samples that were positive to GC-MS were analyzed by LC-APCI-MS in order to detect further polar byproducts or to improve the determination of previously detected polar analytes. The transformation products of triazine pesticides like deethylatrazine (DEA) and deisopropylatrazine (DIA) and compounds such as diuron and several chlorophenols were positively identified by LC-APCI-MS. The present methodology has also been used for searching for new analytes not included in the EC 76/464 list, like Irgarol, DEA and DIA. In addition it was applied to target pollutants in 43 river water samples from Portugal during a pilot survey from April to July 1999. Atrazine followed by simazine and 2,4,6-trichlorophenol were the most ubiquitous compounds detected in this area. The levels detected of the different compounds were in the range of: 0.01-2.73 microg/l, 0.05-0.74 microg/l, 0.02-1.65 microg/l, 0.02-5.43 microg/l, 0.01-0.40 microg/l, 0.01-0.26 microg/l, 0.02-0.61 microg/l, 0.01-3.90 microg/l, 0.01-1.24 microg/l, 0.02-2.3 microg/l, 0.01-0.13 microg/l and 0.01-0.5 microg/l for atrazine, simazine, terbuthylazine, alachlor, metolachlor, Irgarol, propanil; tributhylphosphate, diuron, 2,4,6-trichlorophenol, deisopropylatrazine and deethylatrazine, respectively.     

Analysis of fumonisins B(1), B(2) and B(3) in corn-based baby food by pressurized liquid extraction and liquid chromatography/tandem mass spectrometry

A sensitive and reliable method using pressurized liquid extraction (PLE) and liquid chromatography (LC)/electrospray ionization (ESI) tandem mass spectrometry with a triple quadrupole (QqQ) analyzer has been developed for the analysis of fumonisin B(1) (FB(1)), fumonisin B(2) (FB(2)) and fumonisin B(3) (FB(3)) in corn-based baby foods. Influence of several extraction parameters that affect PLE efficiency such as temperature, pressure, solvent extraction, number of cycles and dispersant/clean-up agents were studied. The selected PLE operating method was: 3g of sample was packed into 11 ml stainless-steel cell and fumonisins were extracted with methanol at 40 degrees C, 34 atm in one cycle of 5 min at 60% flush. The analytes were ionized in ESI operating with positive ion mode and identified by selecting two monitoring transitions, permitting quantification and confirmation in a single injection. Recoveries ranged from 68% to 83% at fortification levels of 200 microg kg(-1) with relative standard deviation (RSD) from 4% to 12%. The limits of quantification were from 2 microg kg(-1) for FB(1) and FB(2), and 5 microg kg(-1) for FB(3), which are below the maximum residue level established by the European Union legislation in infant formulas. The proposed method was successfully applied to the analysis of twenty seven samples of baby food products collected from different markets, and one positive sample with a content of 15.9 microg kg(-1) for FB(1), 9.2 microg kg(-1)for FB(2) and 5.8 microg kg(-1) for FB(3) was obtained. Given the simplicity and potential of the proposed procedure, its application for safety control is recommended.     

Application of liquid-phase microextraction and gas chromatography-mass spectrometry for the determination of polychlorinated biphenyls in blood plasma

This study investigated the feasibility of applying liquid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS) to determine polychlorinated biphenyls (PCBs) in blood plasma. An efficient and simple extraction technique has been developed for the enrichment of PCBs from human blood plasma samples using single-step liquid-phase microextraction (LPME) in conjunction with a hollow fibre membrane (HFM). An eight PCB congener mixture was spiked into 2.5 ml of blood plasma, and the solution was then adjusted to pH 10.5 with a salinity of 20% (w/v) prior to making the total volume to 5 ml with ultrapure water. The porous HFM, filled with 3 microl of organic solvent, was then immersed into the solution, which was continuously agitated at 700 rpm for 30 min. Extract (1 microl) containing the pre-concentrated analytes was then injected into a GC-MS without further pre-treatment. Using an optimised extraction procedure, a large enrichment factor of the analytes, i.e. up to 241-fold was achieved in 30 min. The procedure resulted in a relative standard deviation of < 11% (n = 6), and a linear calibration range from 2.5 to 150 microg/l (r > 0.999), and detection limits between 0.07 and 0.94 microg/l, respectively. To demonstrate the feasibility of the procedure, PCB concentrations were determined in actual blood samples collected from the local population in Singapore using the optimised LPME technique.     

Simultaneous determination of cyclophosphamide, ifosfamide, doxorubicin, epirubicin and daunorubicin in human urine using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry: bioanalytical method validation

A reversed-phase high-performance liquid chromatography (rp-HPLC) system interfaced with an electrospray ionization (ESI) source coupled to tandem mass spectrometry (MS/MS) was developed and validated for the determination of cyclophosphamide (CP), ifosfamide (IF), daunorubicin (DNR), doxorubicin (DXR), and epirubicin (EPI) in human urine. The analysis of samples containing multiple analytes with a dissimilar range of polarities was carried out using a conventional reversed-phase chromatographic BDS Hypersil C8 column. The analytical run was 15 min. The triple quadrupole mass spectrometer was operated in positive ion mode and multiple reaction monitoring (MRM) was used for drug quantification. The method was validated over a concentration range of 0.2 to 4.0 microg.L(-1) for CP, IF, DXR, EPI and 0.15-2.0 microg.L(-1) for DNR in human urine. The lower limit of quantification (LLOQ) was 0.2 microg.L(-1) for CP, IF, EPI and was set at 0.3 and 0.15 microg.L(-1) for DXR and DNR, respectively. The relative standard deviations (RSD%) were <11.2% for inter- and intra-day precisions. The overall accuracy was also within 114.7% for all analytes at the concentrations of the quality control samples. The potential of ionization suppression resulting from the endogenous biological material on the rp-HPLC/MS/MS method was evaluated and measured. The feasibility of the proposed HPLC/ESI-MS/MS procedure was demonstrated by analyzing urine samples from pharmacy technicians and nurses working in hospitals or personnel employed in drug-manufacturing plants.     

Development and validation of a liquid chromatography-electrospray tandem mass spectrometry method for mebendazole and its metabolites hydroxymebendazole and aminomebendazole in sheep liver

A quantitative liquid chromatography-electrospray tandem mass spectrometry method for the determination of mebendazole and its hydrolysed and reduced metabolites in sheep liver has been developed and validated. The benzimidazole substances were extracted with ethyl acetate after the sample mixture had been made alkaline. The HPLC separation was performed on a reversed-phase C18 column with gradient elution using a mobile phase consisting of water containing 0.1% formic acid and acetonitrile. The analytes were detected after atmospheric pressure electrospray ionization on a tandem quadrupole mass spectrometer in MS-MS mode. The components were measured by the MS-MS transitions of the molecular ion to the two most abundant daughter ions. The detection limits are lower than 1 microg kg(-1). For this application, the validation limit was set at 50 microg kg(-1). The examined validation parameters were in accordance with the permitted tolerances ranges stipulated in the proposed new European validation criteria for residue surveillance. For the three analytes, the overall recovery was higher than 90%. The RSD for the repeatability ranged from 5 to 11%. The range for the within-laboratory reproducibility was between 2 and 17%. The decision limits for mebendazole, the hydrolysed and the reduced metabolite were 56.6, 61.8 and 64.2 microg kg(-1), respectively. The detection capabilities for these substances were 60.0, 86.1 and 90.9 microg kg(-1), respectively.     

Residue analysis of macrolides in poultry muscle by liquid chromatography-electrospray mass spectrometry

A liquid chromatography-mass spectrometry method is proposed for the determination of seven macrolides authorised in the EU as veterinary drugs for food-producing animals. Sample treatment involves extraction of the analytes with a water-methanol mixture containing metaphosphoric acid and clean-up by SPE with a cation-exchange cartridge. Separation was carried out in an end-capped silica-based C18 column and mobile phases consisting of water/acetonitrile mixtures containing trifluoroacetic acid. A gradient elution, from 28 to 40% acetonitrile was used. Detection was performed by mass spectrometry with electrospray ionisation in the positive mode. Several parameters affecting the mass spectra were studied. The protonated molecular ion was selected for quantitation purposes under selected ion monitoring mode. Detection limits were in the range 1-20 microg l(-1). Recoveries ranged between 56 and 93% with RSD lower than 12%. The method has been successfully applied for multiresidue determination of seven macrolides below the MRLs established by the European Union.     

液相色谱-串联质谱法检测玩具中的3种异噻唑啉酮类防腐剂

建立了液相色谱-串联质谱快速测定玩具中异噻唑啉酮类防腐剂(2-甲基-4-异噻唑啉-3-酮、5-氯-2-甲基-4-异噻唑啉-3-酮和1,2-苯并异噻唑啉-3-酮)的分析方法。样品经去离子水超声提取后进行液相色谱-串联质谱分析。色谱流动相为甲醇-水(15:85, v/v),等度洗脱,在选择反应监测(SRM)模式下定性和定量分析。3种被分析物的工作曲线线性范围均为2.0～1 000 μg/L,方法的定量限(信噪比大于10)为0.04 mg/kg,灵敏度优于欧盟玩具协调标准EN71-11-2005中推荐的方法。两种类型玩具样品中的加标回收率分别为95.9%～105.2%和94.7%～102.8%,精密度分别为3.04%～4.96%和2.36%～4.79%。应用本方法对10种玩具样品进行了测试,结果完全能满足欧盟玩具协调标准EN71-9-2005对玩具中异噻唑啉酮类防腐剂的检测要求。     

Determination of ondansetron and its hydroxy metabolites in human serum using solid-phase extraction and liquid chromatography/positive ion electrospray tandem mass spectrometry

Ondansetron and its hydroxylated metabolites were determined in human serum using solid-phase extraction (SPE) and liquid chromatography/positive ion electrospray tandem mass spectrometry. Pyrimethamine was used as the internal standard. The analytes were eluted from the SPE cartridge using 2 x 1 ml of methanol containing 0.5% triethylamine, evaporated under vacuum and the residue was reconstituted in the mobile phase. The liquid chromatographic separation was achieved on a silica column using a mobile phase of aqueous 20 mM ammonium acetate (pH 4.7)-acetonitrile (85 : 15, v/v) at a flow-rate of 0.4 ml min(-1). The method was linear over the range 1-500 ng ml(-1) for ondansetron and each of the metabolites in human serum. The intra-day accuracy was better than 9.1% and the precision was <10.3%; the inter-day accuracy was better than 9.5% and the precision was <12.6%. The limit of detection was 250 pg ml(-1) based on a signal-to-noise ratio of 3. The absolute recovery from serum for all analytes was >90%.     

凝胶渗透色谱净化-超高效液相色谱-串联质谱法测定皮革制品中7种尼泊金酯类防腐剂

利用超高效液相色谱-串联质谱(UPLC-MS/MS)结合凝胶渗透色谱(GPC)技术,建立了一种快速分离和测定皮革制品中7种尼泊金酯类防腐剂的分析方法。样品经超声提取、浓缩、GPC净化,甲醇-水溶液(1:1, v/v)溶解,采用Acquity UPLCBEH C18柱(50 mm×2.1 mm, 1.7 μm)分离,以甲醇和水为流动相,梯度洗脱,电喷雾负离子模式电离,采用多反应监测模式检测和外标法定量。该方法在0.1～1.0 mg/L范围内线性关系良好(r＞0.99);在添加量为0.5～3.0 mg/kg时,平均回收率为(79.44±5.67)%～(98.07±9.50)%,相对标准偏差(RSD)为4.24%～14.00%;方法的检出限(LOD)为4～12 μg/kg,定量限(LOQ)为13.2～39.6 μg/kg。该方法操作简便、快捷、灵敏、准确,适合皮革中多种尼泊金酯类防腐剂的确证和定量测定。     

Simultaneous determination and pharmacokinetics of five alkaloids in rat plasma by ultra high performance liquid chromatography with tandem mass spectrometry after the oral administration of Corydalis bungeana Turcz extract

Pharmacokinetic studies were conducted on rats for protopine, corynoline, 7′‐(3′,4′‐dihydroxyphenyl)‐N‐[(4‐methoxyphenyl)‐ethyl]propenamide, acetylcorynoline, and 8‐oxocorynoline, five main active components from Corydalis bungeana Turcz (C. bungeana Turcz). An ultra high performance liquid chromatography with tandem mass spectrometry method has been developed and validated for the simultaneous determination of the pharmacokinetic characteristics of these components in rat plasma. Chromatographic separation was achieved on an Agilent SB‐C₁₈ column (1.8 μm, 150 × 2.1 mm) using a gradient elution program with a mobile phase consisting of acetonitrile and water containing 0.1% acetic acid at a flow rate of 0.3 mL/min. The analytes were detected in the multiple reaction monitoring mode with positive electrospray ionization. Lower limits of quantification were >0.680 ng/mL and matrix effects ranged from 91.26 to 100.38%. The mean extraction recoveries of quality control samples were less than 79.32%, and the precision and accuracy were within the acceptable limits. All analytes were proven to be stable during sample storage and analysis procedures. The validated method was successfully applied to the pharmacokinetic study of five alkaloid components after oral administration of C. bungeana Turcz extract to rats. The obtained results may be helpful to reveal the mechanism of action and to guide the clinical application of C. bungeana Turcz.     

Determination of famotidine in low-volume human plasma by normal-phase liquid chromatography/tandem mass spectrometry

A rapid, sensitive and robust assay procedure using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) for the determination of famotidine in human plasma and urine is described. Famotidine and the internal standard were isolated from plasma samples by cation-exchange solid-phase extraction with benzenesulfonic acid (SCX) cartridges. The urine assay used direct injection of a diluted urine sample. The chromatographic separation was accomplished by using a BDS Hypersil silica column with a mobile phase of acetonitrile-water containing trifluoroacetic acid. The MS/MS detection of the analytes was set in the positive ionization mode using electrospray ionization for sample introduction. The analyte and internal standard precursor-product ion combinations were monitored in the multiple-reaction monitoring mode. Assay calibration curves were linear in the concentration range 0.5--500 ng ml(-1) and 0.05--50 microg ml(-1) in plasma and urine, respectively. For the plasma assay, a 100 microl sample aliquot was subjected to extraction. To perform the urine assay, a 50 microl sample aliquot was used. The intra-day relative standard deviations at all concentration levels were <10%. The inter-day consistency was assessed by running quality control samples during each daily run. The limit of quantification was 0.5 ng ml(-1) in plasma and 0.05 microg ml(-1) in urine. The methods were utilized to support clinical pharmacokinetic studies in infants aged 0-12 months.     

Development of a simultaneous liquid-liquid extraction and chiral derivatization method for stereospecific GC-MS analysis of amphetamine-type stimulants in human urine using fractional factorial design

A stereospecific gas chromatography-mass spectrometry analysis method for amphetamine-type stimulants in human urine was recently developed. For maximum efficiency, liquid-liquid extraction and chiral derivatization of the analytes using (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride were performed simultaneously. The effects of (1) use of saturated sodium chloride in 2.0 m sodium hydroxide, (2) extraction solvent volume, (3) percentage of triethylamine, (4) derivatization reagent volume, (5) sample mixing time, (6) incubation temperature and (7) incubation time on method sensitivity and variability were assessed using a two-level, eight-run Plackett-Burman design followed by a fold-over design. The use of saturated sodium chloride solution and the derivatization reagent volume were significant factors (ANOVA, p < 0.01). The saturated sodium chloride solution decreased sensitivity whereas an increased volume of derivatization reagent increased sensitivity. Calibration curves for all analytes were linear between 5 and 500 microg/L, with correlation coefficients of >0.99. Detection limits were 相似文献   

Screening for and validated quantification of phenethylamine-type designer drugs and mescaline in human blood plasma by gas chromatography/mass spectrometry

In recent years, several newer designer drugs of the so-called 2C series such as 2C-D, 2C-E, 2C-P, 2C-B, 2C-I, 2C-T-2, and 2C-T-7 have entered the illicit drug market as recreational drugs. Some fatal intoxications involving 2C-T-7 have been reported. Only scarce data have been published about analyses of these substances in human blood and/or plasma. This paper describes a method for screening and simultaneous quantification of the above-mentioned compounds and their analog mescaline in human blood plasma. The analytes were analyzed by gas chromatography/mass spectrometry in the selected-ion monitoring mode, after mixed-mode solid-phase extraction (HCX) and derivatization with heptafluorobutyric anhydride. The method was fully validated according to international guidelines. Validation data for 2C-T-2 and 2C-T-7 were unacceptable. For all other analytes, the method was linear from 5 to 500 microg/L and the data for accuracy (bias) and precision (coefficient of variation) were within the acceptance limits of +/-15% and <15%, respectively (within +/-20% and <20% near the limit of quantification of 5 microg/L).     

Simultaneous determination of paracetamol and caffeine by flow injection-solid phase spectrometry using C18 silica gel as a sensing support.

A continuous and simple UV-photometric flow-through biparameter-sensing device has been developed for the simultaneous determination of paracetamol and caffeine at 275 nm. The sensor is based on temporary sequentiation in the arrival of the analytes to the sensing zone by on-line separation using C18 bonded phase beads (the same as that used in the sensing zone) placed into a minicolumn just before the flow cell. The sample containing these compounds is injected into the carrier solution; paracetamol is determined first because it passes through the minicolumn, while caffeine is strongly retained in it. Then, caffeine is conveniently eluted from the precolumn and develops its transitory signal. Using 200 microl of a sample and deionized water as a carrier, the analytical signal showed a very good linearity in the ranges of 10-160 microg ml(-1) and 3.5-50 microg ml(-1) with detection limits of 0.75 and 0.56 microg ml(-1) for paracetamol and caffeine, respectively. If deionized water with the pH adjusted at 12 was used as a carrier solution, these parameters were 25-400 and 4-55 microg ml(-1) with 2.0 and 0.50 microg ml(-1) as the detection limits, respectively. The biparameter optosensor was satisfactorily applied to the simultaneous determination of these two analytes in pharmaceuticals.     

Quantitative determination of five ergot alkaloids in rye flour by liquid chromatography-electrospray ionisation tandem mass spectrometry

A confirmatory method for detecting five ergot alkaloids, ergocristine, ergotamine, ergonovine, ergocornine and alpha-ergokryptine, in rye flour is described using high performance liquid chromatography coupled to tandem mass spectrometry detection by monitoring two transition reactions per analyte. The procedure entails a liquid-liquid extraction followed by a clean-up step using a C18 solid-phase extraction (SPE) cartridge. An analogue compound, methysergide hydrogen maleinate, was used to assess both repeatability sample preparation and potential MS response fluctuations. The method was fully validated according to the European Union (EU) criteria. Detection and quantification limits of all analytes were calculated ranging from 7 to 11 microg/kg and from 23 to 37 microg/kg, respectively. Fifteen rye flour samples were investigated with the newly developed method, and none of them were above the current Swiss limits of 200mg/kg for total ergot alkaloids.     

Development and validation of a gas chromatographic-mass spectrometric method for simultaneous identification and quantification of marker compounds including bilobalide,ginkgolides and flavonoids in Ginkgo biloba L. extract and pharmaceutical preparations

A gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the simultaneous determination of seven major chemical markers (bilobalide, ginkgolides A, B, C, kaempferol, quercetin and isorhamnetin) in phytopharmaceuticals of Ginkgo biloba L. The intra-day relative standard deviations (RSD) and inter-day RSD's were based on the analysis of the standardized Ginkgo biloba L. extract on the same day and on the following 3 consecutive days. The intra-day RSD's ranged from 1.21% (bilobalide) to 6.20% (kaempferol). The inter-day RSD's ranged from 2.10% (bilobalide) to 10.42% (isorhamnetin). Mean recoveries ranged from a low of 63.0 +/- 5.3% (isorhamnetin) to a maximum of 103.5 +/- 6.0% (ginkgolide A). Calibration curves were linear in ranges between 2.73 and 36.36 microg/ml for the markers. Limits of detection ranged from a low of 0.5 microg/ml (bilobalide) to a high of 2.5 microg/ml (quercetin). The limits of quantitation were a low of 1.1 microg/ml (gingkolides A, B, C) to a high of 7.5 microg/ml (kaempferol). The method was applied to a standard extract (>6% total terpenoids and >24% total flavonoids) and six ginkgo capsule phytopharmaceuticals.     

Simultaneous determination of seventeen glucocorticoids residues in milk and eggs by ultra-performance liquid chromatography/electrospray tandem mass spectrometry

A comprehensive analytical method has been developed and validated for the simultaneous determination of seventeen glucocorticoid residues in eggs and milk. The mass spectrometer parameters, the composition of the mobile phase and the sample preparation method were firstly optimized to obtain maximum sensitivity. The samples were deconjugated with beta-glucuronidase/arylsulfatase enzyme and concentrated using an Oasis HLB solid-phase extraction cartridge, followed by cleanup with a dual Sep-pak silica and aminopropyl cartridge. The analytes were quantified by ultra-performance liquid chromatography (using a C18 column)/electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS) operating in the negative ion mode. The assay for the 17 glucocorticoids was linear over the range of 1-200 microg/L for milk and egg samples with a high correlation coefficient (>0.99). The limits of quantification (LOQs) for the target analytes were 0.04-1.27 microg/kg for the egg samples and 0.03-0.73 microg/kg for the milk samples. The average extraction recoveries of the glucocorticoids from eggs and milk at two concentration levels (spiked at 0.40 and 2.00 microg/kg) were 65.6-118.7% and 61.5-119.6%, respectively, with relative standard deviations between 1.8-17.0% and 2.4-18.4%, respectively. Because of its high sensitivity, good precision and specificity, the method was found to be suitable for trace analysis of synthetic and natural glucocorticoids in complex biosamples such as eggs and milk.