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ObjectiveTo establish a method for the determination of 1,1,1,2-tetrachloroethane (TeCA) and 1,1,2,2-TeCA in human urine using liquid-liquid extraction-gas chromatography. Methods The 5.0 mL urine sample was mixed with 2.0 g anhydrous sodium sulfate and 5.0 mL ethyl acetate, then vortexed mixing. The 1.0 mL extraction was separated by 100% dimethylpolysiloxane capillary gas chromatography column, detected by flame ionization detector, and quantified by an external standard method. Results The linear ranges of 1,1,1,2-TeCA and 1,1,2,2-TeCA were 0.250-50.750 mg/L, with both correlation coefficients of >0.999 9. The detection limit of 1,1,1,2-TeCA in urine was 0.020 mg/L, and the lower limit of quantification was 0.060 mg/L. The average recovery was 88.02%-101.32%, and the within-run and between-run relative standard deviations (RSDs) were 0.11%-0.47% and 0.39%-1.09%, respectively. The detection limit of 1,1,2,2-TeCA in urine was 0.050 mg/L, and the lower limit of quantification was 0.150 mg/L. The average recovery was 93.42%-101.32%, and the within-run and between-run RSDs were 0.28%-1.04% and 0.50%-1.03%, respectively. Both the 1,1,1,2-TeCA and 1,1,2,2-TeCA cannot be stored at room temperature. The 1,1,2,2-TeCA can be stored at 4 ℃ for at least three days. At -20 ℃, the 1,1,1,2-TeCA can only be stored for one day, while 1,1,2,2-TeCA can be stored for at least five days. Conclusion This method has high sensitivity, good specificity, simple sample pretreatment, and more intuitive and reliable results. It can be used to determine the level of 1,1,1,2-TeCA and 1,1,2,2-TeCA in urine of occupational population.
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Abstract Dasatinib, a potent oral multi-targeted kinase inhibitor against Src and Bcr-Abl, can decrease inflammatory response in sepsis. A simple and cost-effective method for determination of an effective dose dasatinib was established. This method was validated in human plasma, with the aim of reducing the number of animals used, thus, avoiding ethical problems. Dasatinib and internal standard lopinavir were extracted from 180 uL of plasma using liquid-liquid extraction with methyl tert-butil ether, followed by liquid chromatography coupled to triple quadrupole mass spectrometry in multiple reaction monitoring mode. For the pharmacokinetic study, 1 mg/kg of dasatinib was administered to mice with and without sepsis. The method was linear over the concentration range of 1-98 ng/mL for DAS in mice and human plasma, with r2>0.99 and presented intra- and interday precision within the range of 2.3 - 6.2 and 4.3 - 7.0%, respectively. Further intra- and interday accuracy was within the range of 88.2 - 105.8 and 90.6 - 101.7%, respectively. The mice with sepsis showed AUC0-t = 2076.06 h*ng/mL and Cmax =102.73 ng/mL and mice without sepsis presented AUC0-t = 2128.46 h*ng/mL. Cmax = 164.5 ng/mL. The described analytical method was successfully employed in pharmacokinetic study of DAS in mice.
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Animals , Male , Mice , Plasma , Chromatography, Liquid/methods , Tandem Mass Spectrometry/methods , Dasatinib/analysis , PharmacokineticsABSTRACT
Aim To develop an LC-MS/MS method for the determination of prucalopride(PCP)in human plasma.Methods Prucalopride -13CD3(dPCP)was used as the internal standard.The analytes were extracted from human plasma through liquid-liquid extraction method using ethyl acetate, followed by being dried, and then the reconstitution was injected into LC-MS/MS systems.Agilent ZORBAX SB C18(3.0×100 mm, 3.5 μm)column and isocratic elution system composing of methanol and 1 mmol·L-1 ammonium acetate(80:20, V/V)provided chromatographic separation of PCP and dPCP.AB Sciex API4000 mass spectrometer equipped with an electrospray ionization source in positive ion mode was employed for mass detection, and data acquisition was carried out in multiple reaction monitoring(MRM)mode.The mass transition ion-pair was followed as m/z 368.4/196.0 for PCP and m/z 374.4/198.0 for dPCP.Results PCP and dPCP were eluted at 3.6 min, with no interference in human blank plasma.PCP in human plasma showed good linearity over the concentration range of 0.058 96-7.547 μg·L-1 with the correlation coefficient of 0.996 3-0.999 6.The lower limit of quantitation of this method was 0.058 96 μg·L-1.The intra-batch and inter-batch accuracy ranged from 98.29% to 108.2%, with good precision(CV<5.2%).The average matrix factors of normal, haemolysed and lipaemic matrix human samples all ranged from 96.48% to 106.3% with CV less than 8.39%.The average extraction recoveries of PCP at low, medium and high concentrations were 89.88%, 95.27% and 94.52% respectively, with CV less than 7.21%.PCP was stable in human samples after 6 h at room temperature, 60 h at -20 ℃, 56 days or three freeze-thaw cycles at -80 ℃; meanwhile, the processed plasma samples remained stable after being stored for 24 hours in autosampler at 8 ℃.Furthermore, PCP in human blood samples was proved to be stable after 4 h at room temperature.Conclusions The present LC-MS/MS method for the determination of PCP in human plasma was convenient, accurate, sensitive, stable, specific and reproducible and was proved to be suitable for the clinical pharmacokinetics and bioequivalence studies of PCP preparations.
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RESUMO O estudo teve como objetivo o desenvolvimento e a validação de um método analítico para detecção e quantificação de ácidos haloacéticos por meio da extração líquido-líquido e da análise por cromatografia gasosa acoplada à espectrometria de massas. Para a validação, consideraram-se parâmetros como linearidade, precisão, limites de detecção e quantificação e seletividade. Adicionalmente, aplicou-se o método para avaliar a formação de ácidos haloacéticos em ensaios de cloração de células de Cylindrospermopsis raciborskii com o oxidante hipoclorito de cálcio, simulando situações em estações de tratamento de água. O método apresentou baixo tempo de análise, excelente seletividade, precisão, repetitividade e sensibilidade, com possibilidade de aplicação para análises de rotina em substituição à cromatografia a gás por captura de elétrons. Observou-se a formação de ácidos haloacéticos durante os ensaios com doses de 2,5 e 5,0 mg.L-1 do oxidante, com destaque para os ácidos dicloroacético e tricloroacético.
ABSTRACT The objective of the study was to develop and validate an analytical method for the detection and quantification of haloacetic acids through liquid-liquid extraction and gas chromatography-mass spectrometry analysis. For validation, parameters such as linearity, precision, detection and quantification limits, and selectivity were considered. Additionally, the method was applied to evaluate the formation of haloacetic acids in in Cylindrospermopsis raciborskii cell chlorination assays with the calcium hypochlorite oxidant, simulating full scale situations in water treatment plants. The method presented low analysis time, excellent selectivity, precision, repeatability, and sensitivity, with possibility of application for routine analysis in substitution gas chromatography by electron capture. The formation of haloacetic acids was observed during the tests with 2.5 and 5.0 mg.L-1 doses of the oxidant, with emphasis on dichloroacetic and trichloroacetic acids.
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OBJECTIVE:To establish a method for concentration determination of anlotinib in human plasma and apply it in the clinic. METHODS :The plasma samples were pretreated by salting-out assisted with liquid-liquid extraction with ammonium acetate as salting out assistant and acetonitrile as solvent. Using voriconazole as internal standard ,LC-MS/MS method was adopted. The separation was performed on Waters X Bridge C 18 column with mobile phase consisting of 0.2% formic acid solution- acetonitrile(gradient elution )at the flow rate of 1 mL/min. The column temperature was set at 40 ℃,and sample size was 10 μL. The split ratio was 3∶7. The electrospray ion source and multiple reaction monitoring mode were used for the analysis. The ion pair of anlotinib and internal standard under positive ion mode were m/z 408.3→339.3 and m/z 350.2→281.3,respectively. RESULTS : Anlotinib showed a good linear relationship in the concentration range of 0.2-200 ng/mL(R2>0.996 7). The lowest limit of quantitation was 0.2 ng/mL. Intra-day and inter-day RSDs were no more than 12% (n=6 or n=3). Accuracies were 90.92%-108.00%(n=6 or n=3). The average extraction recoveries were 87.51%-100.00%(RSD<8%,n=6). The average matrix effects were 96.66%-99.93%(RSD<5%,n=6). The plasma concentration of 3 patients with NSCLC treated with anlotinib was 8.74-65.60 ng/mL. CONCLUSIONS :The method is simple ,accurate and specific ,and is suitable for the plasma concentration monitoring of anlotinib in NSCLC patients.
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@#A deuterated internal standard quantitative analysis method based on liquid-liquid extraction-ultra performance liquid chromatography-tandem mass spectrometry (LLE-UPLC-MS/MS) for simultaneous determination of 10 illicit drugs in wastewater was established.Wastewater samples were concentrated by liquid-liquid extraction with dichloromethane: ethyl acetate (1∶1), and separated by a linear gradient of 0.1% formic acid-5 mmol/L ammonium formate aqueous solution and acetonitrile on a C18 column. The samples were then detected by ESI positive ion mode and multiple reaction monitoring mode (MRM) for quantitative analysis.All analytes had a good linear relationship (r ≥ 0.995 7) within the range of their respective standard curves; the limit of quantification was 1 ng/L (except amphetamine at 2.5 ng/L); the relative recovery rate ranged from 96.36% to 106.43%, and the intra- and inter-day precisions were less than 4.70%.This method is accurate, reliable and reproducible, and is suitable for the quantitative determination of 10 illicit drugs in wastewater.It is also suitable for wastewater with complex matrixes that affect solid phase extraction and enrichment.It provides a new analytical method for real-time monitoring of drug abuse.
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Objective To establish an analysis method for simultaneous determination of 13 sedative substances and their metabolites in blood by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology and to apply the method to actual cases. Methods The samples were extracted with ethyl acetate after an internal standard was added. The extract was condensed until it was nearly dry and then its residues were dissolved with methanol, filtered through 0.22 μm filter and finally determined. The 13 sedative substances and their metabolites were separated through the C18 chromatographic column, then gradient elution was performed on them with methanol and 20 mmol/L ammonium formate (containing 0.1% formic acid) solution. After that, they were determined in the electrospray positive ion mode and quantified by internal standard method. Results The 13 sedative substances and their metabolites in blood showed good linearity in the range of 5-200 μg/L with correlation coefficients ranging from 0.990 3 to 0.999 8. The detection limits were 0.1-1.0 μg/L. Recovery rates of sedative substances were in the range of 71.2%-93.4% when solutions with concentrations of 10, 50 and 200 μg/L were added. The deviations of intra-day and inter-day relative standard deviations (RSD) were not more than 8.6%. Accuracies (bias) were within ±9.8%. Conclusion This method is rapid, simple, effective and sensitive, and can be applied to analysis of 13 sedative substances and their metabolites in blood in forensic toxicology.
Subject(s)
Chromatography, High Pressure Liquid , Chromatography, Liquid , Forensic Toxicology , Hypnotics and Sedatives , Tandem Mass SpectrometryABSTRACT
@#An analytical liquid-liquid extraction-gas chromatography–mass spectrometry (LLE-GC-MS) method was established for the determination of genotoxic impurities including methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS) and isopropyl methanesulfonate (IMS) in methanesulfonic acid. An Agilent HP-1MS capillary column (30 m × 0.32 m, 1 μm) was used for separating the analytes by programmed heating with the inlet temperature of 220 °C. Mass spectrometry was operated in positive ion mode, and selective ion monitors were set at m/z 80 for MMS, m/z 79 for EMS, m/z 123 for IMS and m/z 56 for internal standard butyl methanesulfonate (BMS). Results showed that the baseline separation of MMS, EMS and IMS was achieved, and the blank extraction solution had no interference; good linearity was achieved in the range of 37-1 480 ng/mL for three alkyl methanesulfonates; The mean recoveries of MMS, EMS, IMS were 104.99%, 107.26%,108.85%, respectively, with RSD ≤ 4.54%. The established method has the characteristics of specific, sensitive, accurate, stable and good versatility, and has been used for the detection and control of alkyl methanesulfonate impurities in methanesulfonic acid from a variety of manufacturers.
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OBJECTIVE: To establish a method for rapid determination of 2,5-hexanedion in urine by liquid-liquid extraction-gas chromatography. METHODS: Two mL of urine simple was acidified using 100 μL of hydrochloric acid. Anhydrous sodium sulfate 0.5 g was added for salting out. Extraction was carried out using 1 mL of chromatographic grade ethyl acetate vortex, separated by Rtx®-WAX chromatographic column, and detected with flame ionization detector. RESULTS: The good linear range of 2,5-hexanedion was 0.25-15.00 mg/L. The correlation coefficient was 0.999 7. The detection limit was 0.08 mg/L and the minimum detection concentration was 0.25 mg/L. The average recovery rate was 93.0%-110.0%. The within-run relative standard deviation(RSD) was 1.9%-5.4% and the between-run RSD was 5.0%-11.2%. CONCLUSION: This method is simple, sensitive and accurate, which is suitable for detecting urine 2,5-hexanedion in occupational n-hexane exposed workers and suspected patients with occupational chronic n-hexane poisoning.
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An ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) method was developed to evaluate the chemical consistency of triterpene acids in ethanol extracts of Poria and acetic ether extracts thereof. First, high resolution mass spectrometry data were obtained with Full scan mode, by comparing with MS data from the reference compounds and literatures, a total of 23 components were unequivocally or tentatively identified in ethanol extracts and acetic ether extracts thereof. Then, a mimic multiple reaction monitoring (mMRM) mode was established using UPLC-QTOF-MS/MS to quantify the triterpene acids in ethanol extracts and acetic ether extracts thereof. Eleven components were absolutely quantified with reference compounds, while 12 components without reference compounds were relatively quantified with peak areas, the transfer and enrichment rate of triterpene acids during liquid-liquid extraction were calculated. It was found all of the 23 triterpene acids identified in Poria ethanol extracts could be transferred into acetic ether extracts with high transfer and enrichment rate. The present study provides not only scientific evidence for further extraction of triterpene acids in Poria by acetic ether, but also an approach for comprehensive evaluation of the chemical consistency of herbal medicine extracts before and after the liquid-liquid extraction.
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Steroid hormone, the component of the endocrine system, plays an extremely important role in body development, immune regulation, and birth control. The accurate determination of steroid hormone is important for the prevention, diagnosis, and treatment of clinical endocrine diseases. In recent years, the determination of endogenous steroid hormones in biological samples has become increasingly widespread in clinical applications. In this article, the commonly used analysis methods of typical blood steroids from 2013 to 2018 were generalized and compared in order to provide more reference for the accurate determination of steroid hormone levels, and also provide more accurate basis for later clinical diagnosis and treatment.
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A selective, sensitive and rugged liquid chromatography–tandem mass spectrometry (LC–MS/MS) assay has been developed for the simultaneous determination of doxepin (Dox) and its pharmacologically active metabolite, nordoxepin (NDox) in human plasma. The analytes and their internal standards (IS) were extracted from 500 μL of human plasma by liquid-liquid extraction using methyl tert-butyl ether. Chromatographic separation was achieved on Hypurity C8 column (100 mm × 4.6 mm, 5 μm) using a mixture of acetonitrile-methanol (95:5, v/v) and 2.0 mM ammonium formate in 93:7 (v/v) ratio. Detection was accomplished by tandem mass spectrometry in the positive ionization and multiple reaction monitoring acquisition mode. The protonated precursor to product ion transitions studied for Dox, NDox, and their corresponding ISs, propranolol and desipramine, were m/z 280.1-107.0, 266.0 -107.0, 260.1-116.1 and 267.1-72.1, respectively. A linear dynamic range of 15.0–3900 pg/mL for Dox and 5.00– 1300 pg/mL for NDox was established with mean correlation coefficient (r2) of 0.9991 and 0.9993, respectively. The extraction recovery ranged from 86.6%–90.4% and 88.0%–99.1% for Dox and NDox, respectively. The intra-batch and inter-batch precision (% CV) across quality control levels was ≤ 8.3% for both the analytes. Stability evaluated under different storage conditions showed no evidence of degradation and the % change in stability samples compared to nominal concentration ranged from 4.7% to 12.3%. The method was successfully applied to a bioequivalence study of 6 mg doxepin hydrochloride orally disintegrating tablet in 41 healthy Indian subjects under fasting and fed conditions.
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OBJECTIVE: To develop a liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for the determination of B07 in rabbit plasma. METHODS: Analytes were separated from plasma by a combination of alkalinized protein precipitation and liquid-liquid extraction with methyl tert-butyl ether. Chromatographic separation was performed on a Waters Symmetry C18 (4.6 mm×150 mm, 5 μm)column with the mobile phase consisted of acetonitrile (containing 0.2% acetic acid)-40 mmol·L-1 ammonium acetate (containing 0.2% acetic acid) in water (80∶20). A tandem mass spectrometer equipped with electrospray ionization source was used as detector and operated in the positive ion mode. Quantification was performed using multiple reaction monitoring (MRM) of the transitions m/z 529.3→335.4 and m/z 237.1→194.1 for B07 and carbamazepine (internal standard), respectively. RESULTS: The method showed a good linearity in a concentration range of 0.31-310 ng·mL-1 for B07 was more than 0.99. The intra- and inter-day precision was less than 15% and the absolute recovery was above 75%. CONCLUSION: This method was selective and rapid, sensitive for investigating blood drug concentrations in rabbit.
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Objective@#To establish a method for determing the trichloroethylene(TCE)and trichloroethanol(TCOH)in blood samples by liquid-liquid extraction-gas chromatography with electron capture detector.@*Methods@#With this method,ether was used as extraction solvent and trichloromethane was used as an internal standard. The whole blood sample was extracted with ether, and dehydrated by anhydrous sodium sulfate. Then the analytes were separated on HP-5 capillary column(30m×0.32mm×0.15μm)and detected byECD.The retention time was for qualitative analysis and the internal standard was for quantitation.@*Results@#The standard curves of TCE and TCOH showed significant linearity between 95.5μg/L-7640.0μg/L(r=0.9997)and 19.0μg/L-1520.0μg/L(r=0.9992). The average recovery was 95.5%-103.6%.The intra-day and inter-day precisions(RSD)were 2.5%-6.8%(n=6)and 1.6%-4.3%(n=6) respectively. The detect limit of TCE and TCOH were 2.10 μg/L and 0.56μg/L(S/N=3)respectively.The blood can be kept 7 days at-20℃ refrigerator without significantly loss.@*Conclusion@#This method is proved to be simple,practical and highly sensitive. It can satisfy the request for the determination of blood samples of humans exposed to TCE.
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This study describes the development of a rapid, selective, precise and sensitive reverse phase high-performance liquid chromatography method for the quantitative determination of Levocetirizine Dihydrochloride (LCD) in human plasma and pharmaceutical dosage form. Extraction of drug from plasma was done by employing optimized liquid-liquid extraction procedure. The sample was analyzed using Acetonitrile: Methanol: 20mM Ammonium Acetate Buffer pH-5 (25:55:20 % v/v/v) as mobile phase. Chromatographic separation was achieved on Prontosil C-18 column (4.6 x 250mm, 5μ particle size) as stationary phase using isocratic elution (at a flow rate of 1 mL/min). The peak was detected using UV-PDA detector set at 232 nm and retention time was found to be 8 min for LCD. The calibration curve obtained was linear (r2= 0.9998) over the concentration range of 2-10 μg/mL. Method was validated for precision, robustness and recovery. The limit of detection (LOD) and limit of quantitation (LOQ) was 0.0057 and 0.174 µg/mL respectively. There was no significant difference between the amount of drug spiked in plasma and the amount recovered and plasma did not interfere in estimation. Thus, the proposed method is suitable for the analysis of LCD in tablet dosage forms and human plasma.
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Abstract Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used by the general population to alleviate inflammation and pain after oral surgeries. Piroxicam is among the most commonly used NSAIDs and excels in controlling pain, swelling, trismus and other common symptoms of inflammation. This study aimed to evaluate different concentrations of piroxicam and its major metabolite, 5'-hydroxypiroxicam, in human plasma samples over time using high performance liquid chromatography (HPLC) after liquid-liquid extraction. Briefly, 10 volunteers participated in this study after approval by the Ethics Committee of Bauru School of Dentistry, Universidade de São Paulo - USP, Brazil. Volunteers received a single dose oral of piroxicam (20 mg) and had blood collected at various times following an established protocol. The methodology of liquid-liquid extraction was effective for determining concentrations of piroxicam in plasma using HPLC in 10 out of 10 volunteers while 5'-hydroxypiroxicam was only detected in 2 out of 10 volunteers.
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Humans , Piroxicam/analogs & derivatives , Piroxicam/blood , Anti-Inflammatory Agents, Non-Steroidal/blood , Chromatography, High Pressure Liquid/methods , Liquid-Liquid Extraction/methods , Reference Values , Time Factors , Piroxicam/pharmacokinetics , Anti-Inflammatory Agents, Non-Steroidal/pharmacokinetics , Naproxen/blood , Naproxen/pharmacokinetics , Reproducibility of ResultsABSTRACT
An analytical procedure for the determination of water-and methanol-extractable pentachlorophenol ( PCP) in soils using vortex assisted liquid-liquid extraction ( VALLE ) and gas chromatography ( GC ) was developed. Significant extraction parameters, such as liquid-liquid ratio and vortex speed were optimized. The recovery of PCP was the highest ( 97. 4%) at the vortex rotation speed of 2000 r/min, with good reproducbility and a small relative sdandard deviation ( RSD, 0. 5%), with regard to the volume ratio of derivatization solution to n-hexane, the recovery of PCP was 103% with an RSD of 0. 7% at 10:4. The linearity of the calibration ranged from 1. 25 μg/L to 4000 μg/L, with a correlation coefficient ( R2 ) of 0. 9999. The detection limit of the PCP in water was below 0. 2 μg/L. Compared with traditional liquid-liquid extraction ( LLE) and solid phase extraction ( SPE) , the VALLE method was more simple and more economic in terms of chemical consumption, also with a recovery of 96. 8% and a RSD of 3. 7%. Four different soils were used to check the reliability of this method. The soils were respectively extracted with water once and methanol three times. The total recoveries were 89. 5%-98. 9% and 88. 7%-98. 4% at the PCP spiking level of 1 and 10 mg/kg, respectively. It is concluded that the VALLE method satisfied the extraction and determination of water and methanol extractable PCP in soils with varying PCP polluting rates.
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A sensitive, selective and high-throughput liquid chromatography–tandem mass spectrometry (LC–ESI–MS/MS) method was developed and validated for the quantitation of tolvaptan in rabbit plasma. Sample clean-up involved liquid–liquid extraction (LLE) and chromatography was performed on Zorbax SB C18 analytical column (50 mm ? 2.1 mm, 3.5 mm) using 0.1%formic acid:methanol (20:80, v/v) as the mobile phase. The parent-product ion transitions for the drug (m/z 449.2-252.1) and IS (m/z 456.2-259.2) were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) and positive ion mode. The method was validated over the concentration range of 0.10–1000.00 ng/mL and successfully applied to a pharmacokinetic study of healthy rabbits.
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Aim: A new, simple, rapid, very sensitive and accurate high performance thin-layer chromatographic (HPTLC) method has been developed and validated for estimation of Gemifloxacin in rabbit plasma. Study Design: Validation study. Methodology: HPTLC was performed on silica gel 60F254 plates with ethanol: ethyl acetate: hexane, 2:7:1 (v/v), as mobile phase. Densitometry scanning was performed in absorbance mode at λ=254 nm. Result: The RF value was 0.21. The response was a linear function of concentration over the range 0.1–0.7μg mL−1 (r2=0.996). A maximum recovery of drug from plasma was obtained by using chloroform and glacial acetic acid. Mean extraction recovery was 80%. Intra-day and inter-day precision (% RSD) of the assay were in the range 1.19–2.85% and accuracy was 1.7-5.66% Conclusion: This method can be applied to pharmacokinetic studies in rabbit plasma.
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Se realizó un estudio comparativo de dos metodologías para la determinación de residuos de plaguicidas en agua potable con el fin de establecer cuál de ellas es más adecuada como metodología de análisis. Las metodologías evaluadas involucraron extracción en fase sólida empleando el adsorbente polimérico LiChrolut®EN y extracción líquido-líquido utilizando n-hexano como solvente de extracción. La determinación se realizó por cromatografía de gases con detectores µ-ECD y NPD. El estudio involucró 50 plaguicidas, entre los que se encuentran diferentes familias químicas, tales como organofosforados, organoclorados y piretroides entre otros. Para comparar las metodologías, se evaluó la capacidad de detección y cuantificación estableciendo los límites de detección y cuantificación; la exactitud con experimentos de recuperación y la dispersión por medio de la precisión. Se estableció que estas presentan detección adecuada frente a las concentraciones máximas permitidas por la normativa colombiana, excepto para el insecticida monocrotofos, para el cual se obtuvo un límite de detección superior al exigido. Los experimentos de recuperación mostraron que la totalidad de plaguicidas organoclorados y piretroides pueden ser analizados empleando extracción líquido-líquido, mientras que la extracción en fase sólida es más adecuada para los plaguicidas más polares, tales como los organofosforados y azoles. Se determinó que 22 compuestos se pueden analizar por cualquiera de las dos metodologías, que por extracción en fase solida es posible analizar 36 de los 50 compuestos evaluados mientras que empleando extracción líquido-líquido se pueden analizar 28 de ellos.
Um estudo comparativo de dois métodos foi realizada para a determinação de resíduos de pesticidas em água potável, a fim de estabelecer qual deles é mais adequado como um método de análise. As metodologias avaliadas envolvendo extracção em fase sólida, utilizando o adsorvente polimérico LiChrolut®EN e extracção líquido-líquido utilizando n-hexano como solvente de extracção. A determinação foi realizada por detectores de GC-ECD e NPD. O estudo envolveu 50 pesticidas, incluindo aqueles que são diferentes famílias químicas, tais como os organofosforados, organoclorados e piretróides, entre outros. Para comparar os métodos, a capacidade de detectar e quantificar a estabelecer os limites de detecção e quantificação foi avaliada; a precisão e as experiências de recuperação usando precisão dispersão. Foi estabelecido que estes apresentaram taxas de detecção adequados para as concentrações máximas permitidas pela legislação colombiana, com exceção de monocrotofós inseticida, para que requerido foi obtido um limite de detecção de. Ensaios de recuperação, mostraram que todos os pesticidas organoclorados e piretróides podem ser analisados utilizando-se extracção líquido-líquido, enquanto que a extracção da fase sólida é mais adequado para os pesticidas mais polares, tais como organofosfatos e azóis. Determinou-se que 22 compostos podem ser analisados por qualquer um de dois métodos, que a extracção de fase sólida, é possível analisar 36 dos 50 compostos avaliados, enquanto utilizando a extracção liquido-liquido 28 pode analisar.
A comparative study of two methodologies for the determination of pesticide residues in drinking water was performed in order to establish which of them is more suitable of a method of analysis. The assessed methodologies involved solid phase extraction using polymeric adsorbent LiChrolut ® EN and liquid-liquid extraction using n-hexane as the extraction solvent; its determination was performed by GC with µECD and NPD detectors. The study involved 50 pesticides, including different chemical families, such as organophosphates, organochlorines and pyrethroids among others. The detection capability was assessed by establishing the limits of detection and quantification, and the accuracy and precision performing recovery experiments. It was determined that the two methodologies have suitable detection regarding the maximum concentrations permitted by the Colombian regulations, except for monocrotophos insecticide, for which a limit of detection obtained was slightly above to the required value. The recovery experiments showed that all organochlorine and pyrethroid pesticides can be analyzed using liquid-liquid extraction, while the solid phase extraction is more suitable for the more polar pesticides such as organophosphates and azoles; It was determined that 22 compounds can be analyzed by either of the two methods, that is possible to analyze 36 of the 50 compounds evaluated by solid phase extraction, while using liquid liquid extraction 28 can be analyzed.