A rapid MCM‐41 dispersive micro‐solid phase extraction coupled with LC/MS/MS for quantification of ketoconazole and voriconazole in biological fluids

A rapid dispersive micro‐solid phase extraction (D‐μ‐SPE) combined with LC/MS/MS method was developed and validated for the determination of ketoconazole and voriconazole in human urine and plasma samples. Synthesized mesoporous silica MCM‐41 was used as sorbent in d ‐μ‐SPE of the azole compounds from biological fluids. Important D‐μ‐SPE parameters, namely type desorption solvent, extraction time, sample pH, salt addition, desorption time, amount of sorbent and sample volume were optimized. Liquid chromatographic separations were carried out on a Zorbax SB‐C₁₈ column (2.1 × 100 mm, 3.5 μm), using a mobile phase of acetonitrile–0.05% formic acid in 5 mm ammonium acetate buffer (70:30, v /v). A triple quadrupole mass spectrometer with positive ionization mode was used for the determination of target analytes. Under the optimized conditions, the calibration curves showed good linearity in the range of 0.1–10,000 μg/L with satisfactory limit of detection (≤0.06 μg/L) and limit of quantitation (≤0.3 μg/L). The proposed method also showed acceptable intra‐ and inter‐day precisions for ketoconazole and voriconazole from urine and human plasma with RSD ≤16.5% and good relative recoveries in the range 84.3–114.8%. The MCM‐41‐D‐μ‐SPE method proved to be rapid and simple and requires a small volume of organic solvent (200 μL); thus it is advantageous for routine drug analysis.     

Multiresidue LC–MS/MS analysis of cephalosporins and quinolones in milk following ultrasound‐assisted matrix solid‐phase dispersive extraction combined with the quick,easy, cheap,effective, rugged,and safe methodology

A sensitive and selective confirmatory method for milk‐residue analysis of ten quinolones and eight cephalosporins by LC‐MS/MS has been developed herein. For the chromatographic separation of target analytes, a Perfectsil ODS‐2 (250 × 4 mm, 5 μm) analytical column was used and gradient elution was applied, using a mobile phase of 0.1% w/w TFA in water and 0.1% w/w TFA in ACN. Ultrasound‐assisted matrix solid‐phase dispersion procedure was applied for the extraction and clean‐up procedure of antimicrobials agents from milk matrix using a mixture of Bond Elut Plexa sorbent and QuEChERS. The method was validated meeting the European Legislation determining selectivity, linearity response, trueness, precision (repeatability and between‐day reproducibility), decision limit, detection capability, and ruggedness following the Youden approach. Recoveries of all antibiotics ranged from 81.7 to 117.9%, while RSD values were lower than 13.7%. Limits of quantification for all examined compounds ranged from 2.4 to 15.0 μg/kg, substantially lower than the maximum residue limits established by the European Union (30–100 μg/kg).     

Residue analysis of tebufenozide and indoxacarb in chicken muscle,milk, egg and aquatic animal products using liquid chromatography–tandem mass spectrometry

We developed an analytical method using liquid–liquid extraction (LLE) and liquid chromatography–tandem mass spectrometry (LC‐MS/MS) to detect and quantify tebufenozide (TEB) and indoxacarb (IND) residues in animal and aquatic products (chicken muscle, milk, egg, eel, flatfish, and shrimp). The target compounds were extracted using 1% acetic acid (0.1% acetic acid for egg only) in acetonitrile and purified using n‐hexane. The analytes were separated on a Gemini‐NX C₁₈ column using (a) distilled water with 0.1% formic acid and 5 mm ammonium acetate and (b) methanol with 0.1% formic acid as the mobile phase. All six‐point matrix‐matched calibration curves showed good linearity with coefficients of determination (R²) ≥0.9864 over a concentration range of 5–50 μg/kg. Intra‐ and inter‐day accuracy was expressed as the recovery rate at three spiking levels and ranged between 73.22 and 114.93% in all matrices, with a relative standard deviation (RSD, corresponding to precision) ≤13.87%. The limits of quantification (LOQ) of all target analytes ranged from 2 to 20 μg/kg, which were substantially lower than the maximum residue limits (MRLs) specified by the regulatory agencies of different countries. All samples were collected from different markets in Seoul, Republic of Korea, and tested negative for tebufenozide and indoxacarb residues. These results show that the method developed is robust and may be a promising tool to detect trace levels of the target analytes in animal products.     

Simultaneous determination of piperaquine and its N‐oxidated metabolite in rat plasma using LC‐MS/MS

A sensitive and efficient liquid chromatography tandem mass spectrometry method was developed and validated for the simultaneous determination of piperaquine (PQ) and its N ‐oxidated metabolite (PQ‐M) in plasma. A simple protein precipitation procedure was used for sample preparation. Adequate chromatographic retention was achieved on a C₁₈ column under gradient elution with acetonitrile and 2 mm aqueous ammonium acetate containing 0.15% formic acid and 0.05% trifluoroacetic acid. A triple‐quadrupole mass spectrometer equipped with an electrospray source was set up in the positive ion mode and multiple reaction monitoring mode. The method was linear in the range of 2.0–400.0 ng/mL for PQ and 1.0–50.0 ng/mL for PQ‐M with suitable accuracy, precision and extraction recovery. The lower limits of detection (LLOD) were established at 0.4 and 0.2 ng/mL for PQ and PQ‐M, respectively, using 40 μL of plasma sample. The matrix effect was negligible under the current conditions. No effect was found for co‐administrated artemisinin drugs or hemolysis on the quantification of PQ and PQ‐M. Stability testing showed that two analytes remained stable under all relevant analytical conditions. The validated method was successfully applied to a pharmacokinetic study performed in rats after a single oral administration of PQ (60 mg/kg).     

Simultaneous determination of major type‐B trichothecenes and the de‐epoxy metabolite of deoxynivalenol in chicken tissues by HPLC–MS/MS

In this study, a specific and sensitive LC–MS/MS method for the simultaneous analysis of type‐B trichothecenes (deoxynivalenol, 3‐acetyldeoxynivalenol, and 15‐acetyldeoxynivalenol) and the de‐epoxy metabolite of deoxynivalenol (de‐epoxy‐deoxynivalenol) in chicken muscle, liver, kidney, and fat tissues was developed and validated. The method involved an extraction step using ethyl acetate, followed by the evaporation of the supernatant, which was further purified by an Oasis HLB SPE cartridge (Waters, Milford, MA, USA). Chromatographic separation was performed on a C₁₈ column by detection with MS in multiple‐reaction monitoring mode and using a gradient elution program with 0.1% formic acid in water and methanol. The correlation coefficients (r) for each calibration curve were >0.99 within the experimental concentration range. The extraction recoveries ranged from 73.7 to 106.4%, with intraday and interday RSD < 11.6% at three levels of concentrations of 2, 10, and 100 μg/kg. The decision limits and the detection capabilities of the analytes in the chicken tissues ranged from 0.16 to 0.92 and 0.68 to 2.07 μg/kg, respectively. The results demonstrated the applicability of this sensitive procedure to the determination of trichothecenes in chicken tissue samples.     

Determination of 19 sulfonamides residues in pork samples by combining QuEChERS with dispersive liquid–liquid microextraction followed by UHPLC–MS/MS

A new simple and rapid pretreatment method for simultaneous determination of 19 sulfonamides in pork samples was developed through combining the QuEChERS method with dispersive liquid–liquid microextraction followed by ultra‐high performance liquid chromatography with tandem mass spectrometry. The sample preparation involves extraction/partitioning with QuEChERS method followed by dispersive liquid–liquid microextraction using tetrachloroethane as extractive solvent and the acetonitrile extract as dispersive solvent that obtained by QuEChERS. The enriched tetrachloroethane organic phase by dispersive liquid–liquid microextraction was evaporated, reconstituted with 100 μL acetonitrile/water (1:9 v/v) and injected into an ultra‐high performance liquid chromatography with a mobile phase composed of acetonitrile and 0.1% v/v formic acid under gradient elution and separated using a BHE C₁₈ column. Various parameters affecting the extraction efficiency were investigated. Matrix‐matched calibration curves were established. Good linear relationships were obtained for all analytes in a range of 2.0–100 μg/kg and the limits of detection were 0.04–0.49 μg/kg. Average recoveries at three spiking levels were in the range of 78.3–106.1% with relative standard deviations less than 12.7% (n = 6). The developed method was successfully applied to determine sulfonamide residues in pork samples.     

Simultaneous determination of spinosad,temephos, and piperonyl butoxide in animal‐derived foods using LC–MS/MS

Pesticides, which are used as plant protection products, can enter the food chain, and exposure to these xenobiotics can cause a wide array of health problems in humans. Therefore, the objective of the present study was to develop an analytical method for the simultaneous determination of residual spinosad (sum of spinosyn A and D), temephos and piperonyl butoxide in porcine muscle, egg, milk, eel, flatfish and shrimp (sampling period: February to June 2018) using liquid chromatography–triple quadrupole tandem mass spectrometry (LC–MS/MS). The target analytes were extracted with a combination of acidified acetonitrile and ethyl acetate and subsequently purified with original QuEChERS kits (composed of magnesium sulfate and sodium chloride) as well as n‐hexane. All analytes were separated on a reversed‐phase analytical column using a mobile phase of (A) 0.1% formic acid containing 10 mm ammonium formate in distilled water and (B) methanol. Good linearity (R² ≥ 0.980) was achieved over the tested concentration range (3.5–35 μg/kg for spinosyn A; 1.5–15 μg/kg for spinosyn D; 5–50 μg/kg for temephos and piperonyl butoxide) in matrix‐matched standard calibrations. Fortified samples at three spiking levels yielded recoveries in the range of 71–105% with relative standard deviations ≤9.2%. The applicability of the method was evaluated via evaluating samples collected from a large wholesale market located in Seoul, and none of the samples contained any of the target analytes. In conclusion, the current approach is simple, efficient and reliable and can successfully determine the residual levels of spinosad, temephos and piperonyl butoxide in complex animal‐derived food products.     

Development and validation of a simple solid‐phase extraction method coupled with liquid chromatography–triple quadrupole tandem mass spectrometry for simultaneous determination of lincomycin,tylosin A and tylosin B in royal jelly

We have developed an analytical method for the determination of lincomycin, tylosin A and tylosin B residues in royal jelly using liquid chromatography–triple quadrupole tandem mass spectrometry analysis. For extraction and purification, we employed 1% trifluoroacetic acid and 0.1 m Na₂EDTA solutions along with an Oasis HLB cartridge. The target antibiotics were well separated in a Kinetex EVO C₁₈ reversed‐phase analytical column using a combination of 0.1% formate acid in ultrapure water (A) and acetonitrile (B) as the mobile phase. Good linearity was achieved over the tested concentration range (5–50 μg/kg) in matrix‐matched standard calibration. The coefficients of determination (R²) were 0.9933, 0.9933 and 0.996, for tylosin A, tylosin B and lincomycin, respectively. Fortified royal jelly spiked with three different concentrations of the tested antibiotics (5, 10 and 20 μg/kg) yielded recoveries in the range 80.94–109.26% with relative standard deviations ≤4%. The proposed method was applied to monitor 11 brand of royal jelly collected from domestic markets and an imported brand from New Zealand; all the samples tested negative for lincomycin, tylosin A and tylosin B residues. In conclusion, 1% trifluoroacetic acid and 0.1 m Na₂EDTA aqueous solvents combined with solid‐phase extraction could effectively complete the sample preparation process for royal jelly before analysis. The developed approach can be applied for a routine analysis of lincomycin, tylosin A and tylosin B residues in royal jelly.     

Development of an ASE‐GC‐MS/MS method for detecting dinitolmide and its metabolite 3‐ANOT in eggs

An accelerated solvent extraction coupled with gas chromatography‐tandem mass spectrometry (ASE‐GC‐MS/MS) method for detecting dinitolmide residue and its metabolite (3‐amino‐2‐methyl‐5‐nitrobenzamide, 3‐ANOT) in eggs was developed and optimized. The samples were extracted using ASE with acetonitrile as the extractant and were purified by passage through a neutral alumina solid‐phase extraction column. Then, the samples were analyzed using the GC‐MS/MS method. The optimized method parameters were validated according to the requirements set forth by the European Union and the Food and Drug Administration. The average recoveries of dinitolmide and 3‐ANOT from eggs (egg white, egg yolk, and whole egg) at the limit of quantification (LOQ), 0.5 maximum residue limit (MRL), 1 MRL, and 2 MRL were 82.74% to 87.49%, the relative standard deviations (RSDs) were less than 4.63%, and the intra‐day RSDs and the inter‐day RSDs were 2.96% to 5.21% and 3.94% to 6.34%, respectively. The limits of detection and the LOQ were 0.8 to 2.8 μg/kg and 3.0 to 10.0 μg/kg, respectively. The decision limits (CC_α) were 3001.69 to 3006.48 μg/kg, and the detection capabilities (CC_β) were 3001.74 to 3005.22 μg/kg. Finally, the new method was successfully applied to the quantitative determination of dinitolmide and 3‐ANOT in 50 commercial eggs from local supermarkets.     

液相色谱串联质谱法测定猪肉和猪肝中9种磺胺类药物的残留

建立了高效液相色谱-串联质谱法(HPLC/MS/MS)同时测定猪肉及猪肝中9种磺胺类药物残留的检测方法.样品经10％的Na2SO4溶液和乙腈-氯仿(10:1)提取,乙腈饱和正己烷去脂,使用乙二胺-N-丙基硅烷(PSA)和十八烷基键合相硅胶(ODS C18-N)两种基质分散净化剂净化,采用LC-MS/MS多反应监测(MRM)正离子模式测定,内标法定量.9种磺胺检出限为0.1 ～0.8 μg/kg,在5,10,20μg/kg 3个浓度添加水平,回收率为74.1％ ～ 115.8％,相对标准偏差均小于6.2％(n=6).     

Development and validation of a confirmatory method for the determination of 12 non steroidal anti-inflammatory drugs in milk using liquid chromatography-tandem mass spectrometry

A rapid and reliable LC-MS/MS method for the simultaneous confirmation of twelve non steroidal anti-inflammatory drugs (NSAIDs) in bovine milk was developed and fully validated in accordance with the European Commission Decision 2002/657/EC. The validation scheme was built in accordance with the MRLs or target analytical levels (EU-CRL recommended concentrations and detection capabilities) of the analytes, except for diclofenac for which the lower level of validation achieved was 0.5 μg kg(-1) whereas its MRL is 0.1 μg kg(-1). The NSAIDs investigated were as follows: phenylbutazone (PBZ), oxyphenylbutazone (OPB), naproxen (NP), mefenamic acid (MF), vedaprofen (VDP), flunixin (FLU), 5-hydroxyflunixin (FLU-OH), tolfenamic acid (TLF), meloxicam (MLX), diclofenac (DC), carprofen (CPF) and ketoprofen (KTP). Several extraction procedures had been investigated during the development phase. Finally, the best results were obtained with a procedure using only methanol as the extraction solvent, with an evaporation step included and no further purification. Chromatographic separation was achieved on a C18 analytical column and the run was split in 2 segments. Matrix effects were also investigated. Data acquisition implemented for the confirmatory purpose was performed by monitoring 2 MRM transitions per analyte under the negative electrospray mode. Mean relative recoveries ranged from 94.7% to 110.0%, with their coefficients of variation lying between 2.9% and 14.7%. Analytical limits expressed in terms of decision limits (CCα) were evaluated between 0.69 μg kg(-1) (FLU) and 27.54 μg kg(-1) (VDP) for non-MRL compounds, and at 0.10 (DC), 15.37 (MLX), 45.08 (FLU-OH), and 62.96 μg kg(-1) (TLF) for MRL compounds. The validation results proved that the method is suitable for the screening and confirmatory steps as implemented for the French monitoring plan for NSAID residue control in bovine milk.     

Validated UHPLC–MS/MS assay for quantitative determination of etoposide,gemcitabine, vinorelbine and their metabolites in patients with lung cancer

A fully valid UHPLC–MS/MS method was developed for the determination of etoposide, gemcitabine, vinorelbine and their metabolites (etoposide catechol, 2′,2′‐difluorodeoxyuridine and 4‐O ‐deacetylvinorelbine) in human plasma. The multiple reaction monitoring mode was performed with an electrospray ionization interface operating in both the positive and negative ion modes per compound. The method required only 100 μL plasma with a one‐step simple de‐proteinization procedure, and a short run time of 7.5 min per sample. A Waters ACQUITY UPLC HSS T3 column (2.1 × 100 mm, 1.8 μm) provided chromatographic separation of analytes using a binary mobile phase gradient (A, 0.1% formic acid in acetonitrile, v /v; B, 0.1% formic acid in water, v /v). Linear coefficients of correlation were >0.995 for all analytes. The relative deviation of this method was <10% for intra‐ and inter‐day assays and the accuracy ranged between 86.35% and 113.44%. The mean extraction recovery and matrix effect of all the analytes were 62.07–105.46% and 93.67–105.87%, respectively. This method was successfully applied to clinical samples from patients with lung cancer.     

Simultaneous analysis of 11 main active components in Cirsium setosum based on HPLC‐ESI‐MS/MS and combined with statistical methods

A novel method based on high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry was developed for simultaneous determination of the 11 major active components including ten flavonoids and one phenolic acid in Cirsium setosum. Separation was performed on a reversed‐phase C₁₈ column with gradient elution of methanol and 0.1‰ acetic acid (v/v). The identification and quantification of the analytes were achieved on a hybrid quadrupole linear ion trap mass spectrometer. Multiple‐reaction monitoring scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. Full validation of the assay was carried out including linearity, precision, accuracy, stability, limits of detection and quantification. The results demonstrated that the method developed was reliable, rapid, and specific. The 25 batches of C. setosum samples from different sources were first determined using the developed method and the total contents of 11 analytes ranged from 1717.460 to 23028.258 μg/g. Among them, the content of linarin was highest, and its mean value was 7340.967 μg/g. Principal component analysis and hierarchical clustering analysis were performed to differentiate and classify the samples, which is helpful for comprehensive evaluation of the quality of C. setosum.     

Determination of cefoperazone and sulbactam in serum by HPLC‐MS/MS: An adapted method for therapeutic drug monitoring in children

A rapid, accurate and specific high‐performance liquid chromatography–tandem mass spectrometry method has been validated for the simultaneous determination of cefoperazone and sulbactam in a small volume sample for children. A Shim‐pack XR‐ODS C₁₈ column with gradient elution of water (0.1% formic acid) and acetonitrile (0.1% formic acid) solution was used for separation at a flow rate of 0.3 mL/min. The calibration curves of two analytes in serum showed excellent linearity over the concentration ranges of 0.03–10 μg/mL for cefoperazone, and 0.01–3 μg/mL for sulbactam, respectively. This method involves simple sample preparation steps and was validated according to standard US Food and Drug Administration and European Medicines Agency guidelines in terms of selectivity, linearity, detection limits, matrix effects, accuracy, precision, recovery and stability. This assay can be easily implemented in clinical practice to determine concentrations of cefoperazone and sulbactam in children.     

固相萃取/液相色谱-串联质谱法检测医院废水中21种抗生素药物残留

应用固相萃取及高效液相色谱-串联质谱技术,建立了医院废水中12种磺胺、4种喹诺酮、3种四环素以及罗红霉素和甲氧苄氨嘧啶等21种抗生素的定性定量方法。水样经HLB小柱萃取富集,使用10%甲醇溶液净化,经甲醇洗脱定容后,以高效液相色谱-串联质谱多反应监测离子模式(MRM)对目标物进行分析。在优化实验条件下,21种抗生素的线性范围为1.0～500μg/L,相关系数r2>0.99,方法检出限为0.005～0.022μg/L。在加标量为0.05μg/L和1.0μg/L时,空白加标回收率分别为71%～105%和76%～111%,RSD均小于15%。以医院废水为基质,21种抗生素的加标回收率为71%～135%,RSD小于25%。该方法简捷、快速、准确,能够实现医院废水中多种抗生素药物残留的同时分析。     

Preparation of dummy template‐imprinted polymers for the rapid extraction of nonsteroidal anti‐inflammatory drugs residues in aquatic environmental samples

A molecularly imprinted polymer was synthesized and applied as a sorbent in the solid‐phase extraction device. The imprinted polymer was characterized by fourier‐transform infrared spectroscopy and scanning electron microscope. The results revealed that imprinted polymer possess sensitive selectivity and reliable adsorption properties for five NSAIDs. The imprinted polymer was successfully applied to the pre‐concentration for five NSAIDs in different water samples prior to UPLC‐MS/MS. In the early studies, several factors were investigated, including pH adjustment, the kind of elution solvent and the volume of elution solvent. Finally, we found that the pH 5 and an aliquot of 2 mL methanol were suitable for the water samples. The limits of detection and limits of quantitation of five nonsteroidal anti‐inflammatory drugs varied from 0.007 to 0.480 μg L⁻¹ and 0.03 to 1.58 μg L⁻¹, respectively. The spiking recoveries of the target analytes were 50.33‐127.64% at the levels of 0.2 μg L⁻¹, 2 μg L⁻¹ and 5 μg L⁻¹. The precision and accuracy of this method showed a great increase compared with traditional solid‐phase extraction. The developed method was successfully applied to extraction and analysis of NSAIDs in different water samples with satisfactory results which could help us better understand their environmental fate and risk to ecological health.     

Temperature‐controlled ionic liquid dispersive liquid‐phase microextraction for the sensitive determination of triclosan and triclocarban in environmental water samples prior to HPLC‐ESI‐MS/MS

A novel dispersive liquid‐phase microextraction method without dispersive solvents has been developed for the enrichment and sensitive determination of triclosan and triclocarban in environmental water samples prior to HPLC‐ESI‐MS/MS. This method used only green solvent 1‐hexyl‐3‐methylimidazolium hexafluorophosphate as extraction solvent and overcame the demerits of the use of toxic solvents and the instability of the suspending drop in single drop liquid‐phase microextraction. Important factors that may influence the enrichment efficiencies, such as volume of ionic liquid, pH of solutions, extraction time, centrifuging time and temperature, were systematically investigated and optimized. Under optimum conditions, linearity of the method was observed in the range of 0.1–20 μg/L for triclocarban and 0.5–100 μg/L for triclosan, respectively, with adequate correlation coefficients (R>0.9990). The proposed method has been found to have excellent detection sensitivity with LODs of 0.04 and 0.3 μg/L, and precisions of 4.7 and 6.0% (RSDs, n=5) for triclocarban and triclosan, respectively. This method has been successfully applied to analyze real water samples and satisfactory results were achieved.     

Simultaneous determination of 32 antibiotics in aquaculture products using LC-MS/MS

An analytical multiclass, multi-residue method for the determination of antibiotics in aquaculture products was developed and validated. A fast, cheap, and straightforward extraction procedure followed by liquid chromatography-tandem mass spectrometry analysis was proposed. This method covers 32 antibiotics of different classes, which are frequently used in aquaculture. Three different extraction procedures were compared, and the extraction with acetonitrile (0.1 vol. % formic acid) showed the best results. The selected extraction procedure was validated at four different fortification levels (10 μg kg^?1, 25 μg kg^?1, 50 μg kg^?1, and 100 μg kg^?1). Recoveries of the tested antibiotics ranged from 70 % to 120 %, with the relative standard deviation (RSD) of triplicates lower than 20 %. The limits of quantification (LOQ) ranged from 0.062 μg kg^?1 to 4.6 μg kg^?1, allowing for the analysis of trace levels of these antibiotics in aquaculture products. The method was applied to the analysis of selected antibiotics in fish and shrimp meat available in the Czech market.     

LC‐MS/MS analysis of Δ9‐tetrahydrocannabinolic acid A in serum after protein precipitation using an in‐house synthesized deuterated internal standard

An assay based on liquid chromatography/tandem mass spectrometry is presented for the fast, precise and sensitive quantitation of Δ9‐tetrahydrocannabinolic acid A (THCA) in serum. THCA is the biogenetic precursor of Δ9‐tetrahydrocannabinol in cannabis and has aroused interest in the pharmacological and forensic field especially as a potential marker for recent cannabis use. After addition of deuterated THCA, synthesized from D₃‐THC as starting material, and protein precipitation, the analytes were separated using gradient elution on a Luna C18 column (150 × 2.0 mm × 5 µm) with 0.1% formic acid and acetonitrile/0.1% formic acid. Data acquisition was performed on a triple quadrupole linear ion trap mass spectrometer in multiple reaction monitoring mode with negative electrospray ionization. After optimization, the following sample preparation procedure was used: 200 μL serum was spiked with internal standard solution and methanol and then precipitated ‘in fractions’ with 500 μL ice‐cold acetonitrile. After storage and centrifugation, the supernatant was evaporated and the residue redissolved in mobile phase. The assay was fully validated according to international guidelines including, for the first time, the assessment of matrix effects and stability experiments. Limit of detection was 0.1 ng/mL, and limit of quantification was 1.0 ng/mL. The method was found to be selective and proved to be linear over a range of 1.0 to 100 ng/mL using a 1/x weighted calibration model with regression coefficients >0.9996. Accuracy and precision data were within the required limits (RSD ≤ 8.6%, bias: 2.4 to 11.4%), extractive yield was greater than 84%. The analytes were stable in serum samples after three freeze/thaw cycles and storage at ?20 °C for one month. Copyright © 2012 John Wiley & Sons, Ltd.     

Development of a fast LC‐MS/MS assay for the determination of deferiprone in human plasma and application to pharmacokinetics

A fast and accurate liquid chromatography/tandem mass spectrometric (LC‐MS/MS) assay was first developed and validated for the determination of deferiprone in human plasma. The analytes were extracted with acetonitrile from only 50 μL aliquots of human plasma to achieve the protein precipitation. After extraction, chromatographic separation of analytes in human plasma was performed using a Synergi Fusion‐RP 80A column at 30 °C. The mobile phase consisted of methanol and 0.2% formic acid containing 0.2 mM EDTA (60:40, v/v). The flow rate of the mobile phase was 0.8 mL/min. The total run time for each sample analysis was 4 min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the precursor‐to‐parent ion transitions m/z 140.1 → 53.1 for deferiprone and m/z 143.1 → 98.1 for internal standard. A linear range was established from 0.1 to 20 µg/mL. The limit of detection was determined as 0.05 µg/mL. The validated method was estimated for linearity, recovery, stability, precision and accuracy. Intraday and interday precisions were 4.3–5.5 and 4.6–7.3%, respectively. The recovery of deferiprone was in the range of 80.1–86.8%. The method was successfully applied to a pharmacokinetic study of deferiprone in six thalassemia patients. Copyright © 2012 John Wiley & Sons, Ltd.