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An innovative fabric phase sorptive extraction-high performance liquid chromatography-diode array detection (FPSE-HPLC-DAD) method is developed and validated herein for the simultaneous extraction and analysis of five common antidepressants (venlafaxine, paroxetine, fluoxetine, amitriptyline, clomipramine) in human urine samples. Separation was obtained using a reverse phase column LiChroCART-LiChrospher®100 RP-8e (5 μm, 250 × 4 mm) with diode array detection monitoring at 235 nm. Gradient elution was applied at a flow rate of 1.2 mL/min with a mobile phase that consisted of acetonitrile and ammonium acetate (0.05 M). Fabric Phase Sorptive Extraction was evaluated for the first time with regards to the extraction of the examined antidepressants from human urine and proved to be a rapid, simple, environmentally friendly, efficient, and selective sample preparation approach. Sol-gel graphene sorbent, coated on cellulose FPSE media, were the most efficient among other with different polarities. The absolute recovery values were 25.5% for venlafaxine, 33.9% for paroxetine, 67.0% for fluoxetine, 43.0% for amitriptyline and 29.0% for clomipramine, while relative recoveries were higher than 90%. The developed method provides satisfactory limit of detection 0.15 ng/μL.

Capsule phase microextraction is introduced herein for the first time to determine four sulfonamide residues in milk samples (sulfanilamide, sulfadiazine, sulfamethizole, and sulfathiazole). The technique eloquently integrates filtration and stirring mechanism into the extraction device, as such no filtration of the sample is needed prior to introducing the extraction device into the sample, and when placed on a magnetic stirrer, the device spins itself in order to diffuse the sample, resulting in faster extraction equilibrium. Microextraction capsules consist of three main parts; a magnet, a cellulose fiber substrate coated with high performance sol-gel hybrid organic-inorganic sorbent, and a porous membrane. Various encapsulated sol-gel sorbents were tested in standard solutions prepared in deionized water and milk samples under different operational conditions. Analyte extraction time and elution time, type of sol-gel sorbent, elution solvent, as well as the ratio of the sorbent to the elution solvent were among the optimized conditions. The protocols that yielded the best absolute recovery rates were subsequently tested in various milk samples. Method validation was performed in terms of linearity, accuracy and precision, reusability and ruggedness using the Youden test. The examined sulfonamides were subsequently analysed by reversed phase high performance liquid chromatography with diode array detection.

A fast fabric phase sorptive extraction method is presented herein for the rapid isolation of selected beta-blocker drugs from human serum and urine. Among many high efficiency sol-gel sorbent coated FPSE membranes, sol-gel CW20 M coated FPSE membrane was identified as the best FPSE membrane for the target beta-blocker drugs possessing logP values ranging from 0.1 (highly polar) to 3.1 (moderately polar). Due to the engineered affinity towards the analytes via complementary intermolecular interactions and high mass transfer rate of the analytes from the bulk sample solution to the FPSE membrane, the extraction is accomplished in relatively short time (15 min) while its high permeability permits the direct extraction of biological samples without any other pretreatment. The advantages of the fabricated extraction membrane were exploited for the determination of six beta-blockers (namely atenolol, nadolol, metoprolol, oxprenolol, labetalol and propranolol) in biological matrices in combination with UHPLC-ESI-MS/MS. Important parameters including extraction time, sample volume, sorbent size, elution solvent, etc. affecting the performance of the extraction were systematically investigated. The linearity of the method was evaluated in the range of 50–5000 ng mL−1 by constructing weighted (1/X) matrix-matched calibration curves. The intra-day and inter-day trueness were ranged between – 17.2 to 13.3% and – 10.8 to 12.6%, respectively. The intra-day and inter-day precision were less than 11.5 and 14.5 %, respectively. The proposed analytical scheme was successfully applied to the determination of the target drugs in human serum and urine.

Galantamine (GAL), donepezil (DON) and rivastigmine (RIV) are cholinesterase inhibitors administered to patients who suffer from Alzheimer’s disease (AD). We have currently developed and validated an HPLC-DAD method for the determination of GAL, DON, RIV in cerebrospinal fluid (CSF), blood serum and urine. The retention times of the drugs were 1.5, 2.2 and 3.1 min, respectively and the total time of analysis was 5 min. Validation was performed in terms of linearity, selectivity, accuracy, precision, and stability. Following validation, the method was applied to clinical CSF, blood serum and urine samples. The currently developed method is a reliable tool for monitoring CSF, serum and urine galantamine, donepezil and rivastigmine levels in patients under treatment with these drugs.

In the present study, a novel, simple, and fast sample preparation technique is described for the determination of four sulfonamides (SAs), namely Sulfathiazole (STZ), sulfamethizole (SMT), sulfadiazine (SDZ), and sulfanilamide (SN) in cow milk prior to HPLC. This method takes advantage of a novel material that combines the extractive properties of graphene oxide (GO) and the known properties of common polyurethane sponge (PU) and that makes sample preparation easy, fast, cheap and efficient. The PU-GO sponge was prepared by an easy and fast procedure and was characterized with FTIR spectroscopy. After the preparation of the sorbent material, a specific extraction protocol was optimized and combined with HPLC-UV determination could be applied for the sensitive analysis of trace SAs in milk. The proposed method showed good linearity while the coefficients of determination (R2) were found to be high (0.991&ndash, 0.998). Accuracy observed was within the range 90.2&ndash, 112.1% and precision was less than 12.5%. Limit of quantification for all analytes in milk was 50 &mu, g kg&minus, 1. Furthermore, the PU-GO sponge as sorbent material offered a very clean extract, since no matrix effect was observed.

A method for the determination of five sulfonamide drugs: sulfadiazine (SDZ), sulfamethazine (SMTH), sulfisoxazole (SIX), sulfadimethoxine (SDMX), sulfaquinoxaline (SQX) in shrimps was developed using a high-pressure liquid chromatography–diode array detection (HPLC–DAD) instrumentation. The drugs were extracted from the samples using a solid-liquid extraction, with a mixture of acetonitrile-methanol and aqueous solution of acetic acid. The separation was achieved with LiChroCART-LiChrospher® 100 RP-18 (5 μm, 250 × 4 mm), and the mobile phase consisted of (A) aqueous solution of acetic acid 0.1% (65%) and (B) mixture of ACN-MeOH 50:50 v/v (35%), delivered at a flow rate of 0.8 mL/min isocratically. A DAD detector was used for the detection of the sulfonamides at 265 nm. The method was validated according to the 657/2002/EC decision of the European Union. The recoveries for within-day repeatability were 90.2–109.0% and for between-day precision 88.6–108.4%. The limit of quantitation for all five suflonamides was 50 μg/kg, and the limit of detection was 15 μg/kg.

Asenapine is a novel atypical antipsychotic drug for the treatment of schizophrenia and acute mania. Although some analytical methods have been published on the determination of the drug in conventional biological samples, such as blood serum and urine, there is currently no method available for alternative biomatrices, such as hair and nail clippings, which are of utmost importance in forensic and clinical toxicology. A reversed-phase analytical column, Inertsil C8, (250 × 4.0 mm) 5 µm (MZ AnalysenTechnik, Mainz, Germany), was used at ambient temperature, with a mobile phase consisting of an acetate buffer (at pH 4.5), acetonitrile and methanol, (50:40:10%, v/v). Separation was achieved isocratically at a flow rate of 1 mL/min. Quantification was performed at 240 nm. Validation of the method was performed in terms of accuracy and precision: intra-day (n = 5) and inter-day (n = 3 × 5). Recovery rates ranged between 95.0% and 102.5% in hair samples and between 98.8% and 105% in nail samples. In hair the li...

Fabric phase sorptive extraction (FPSE), a recently introduced novel sample preparation technology, has been evaluated for the extraction of benzodiazepines from human blood serum. FPSE utilizes a flexible fabric surface as the substrate platform for creating sol-gel hybrid organic-inorganic sorbent coatings. FPSE media can be introduced directly into the sample containing the target analyte(s), requiring no need for prior sample pretreatment or clean-up. Benzodiazepines were selected as model analytes because they represent one of the most widely used therapeutic drugs in psychiatry and are also amongst the most frequently encountered drugs in forensic toxicology. The chromatographic separation of target analytes was performed on a LiChroCART-LiChrospher®100 RP-18e (5 µm, 250 × 4 mm) analytical column, operated at room temperature. Ternary gradient elution was applied with a mobile phase that consisted of acetonitrile, methanol and ammonium acetate (0.05 M), which was delivered at a flow rate of 1.0 mL/min. Diode array detection was performed with monitoring at 240 nm. FPSE was performed using cellulose fabric extraction media coated with sol-gel poly(ethylene glycol) (sol-gel PEG). Absolute recovery values in the equilibrium state for the examined benzodiazepines were found to be 27% for bromazepam, 63% for lorazepam, 42 % for diazepam and 39% for alprazolam. Copyright © 2015 John Wiley & Sons, Ltd.

Donepezil is an acetylcholinesterase inhibitor administered to patients who suffer from Alzheimer’s Disease (AD). We have currently developed and validated a UHPLC-DAD method for the determination of donepezil in cerebrospinal fluid. The retention time of the drug was 2.4 min and the total time of analysis was 6 min. Validation was performed in terms of linearity, selectivity, accuracy, precision, and stability. Following validation, the method was applied to clinical cerebrospinal fluid samples. The currently developed method is a reliable tool for monitoring CSF donepezil levels in patients under treatment with this drug.

A highly selective molecularly imprinted polymer sorbent was synthesized and employed for the simultaneous determination of six sulfonamide antibiotic residues (sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfamerazine and sulfamethizole) in milk samples. Multi-analyte imprinted particles were used as sorbent in solid phase extraction. Sulfonamides were separated on a high-performance liquid chromatography column (Merck-Lichrospher RP18e, 5 μm 250 × 4 mm) and further identified and quantified by diode array detection. Several parameters including required loading of the molecularly imprinted polymer sorbent, mass of milk, volume and type of elution solvent, as well as time for absorption and elution were investigated to obtain optimal experimental conditions. For comparison purpose, a non-imprinted polymer was applied under the optimum conditions. The validation study according to the European Union Decision 2002/657/EC was based on the investigation of linearity, selectivity, stability, limits of detection and quantitation, decision limit, detection capability, trueness, precision and ruggedness according to Youden's approach. The decision limit and detection capability values in the milk were achieved from 101.9 to 113.5 μg.kg−1 and from 114.4 to 135.4 μg.kg−1, respectively, depending on the target sulfonamide drug. Finally, the optimized protocol was successfully applied to commercial milk samples as well as to human breast milk. This article is protected by copyright. All rights reserved

The authors in a previous work had reported on the determination of seven quinolone antibiotics in gilthead sea bream using liquid chromatography–tandem mass spectrometry, which is a rather expensive and not always available analytical technique. In this work, photodiode array detection is used, so that no sophisticated instrumentation is necessary, following the same sample preparation procedure. A high performance liquid chromatography method for the determination of seven quinolone antibiotics in fish feed and gilthead sea bream (Sparus aurata L.) tissue was developed and validated in terms of selectivity, linearity, accuracy, precision, sensitivity, robustness, and stability, according to European Decision 2002/657/EC. Ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine were separated on a Perfectsil ODS-3 (250 mm × 4 mm, 5 µm) column by gradient elution, using a mobile phase consisting of 0.1% trifluoroacetic acid (pH = 1), acetonitrile, and methanol...

QuEChERS (quick, easy, cheap, effective, rugged and safe) dispersive extraction was applied for the extraction of tetracyclines (oxytetracycline, tetracycline, chlorotetracycline and doxycycline) from milk. Target analytes were determined by an accurate and sensitive chromatographic analytical method, which was validated in terms of 2002/6572/EC decision. The analytes were separated on an Orbit 100C4 (5 &mu, m, 250 &times, 4.0 mm) analytical column under a gradient mobile phase composed of a mixture of 0.01 M oxalic acid, 10&minus, 4 M Na2EDTA and acetonitrile. For the extraction of isolated compounds from sorbent, a methanol and 0.01 M oxalic acid mixture (1:1 v/v) was used, leading to relative recovery rates from 83.07% to 106.3% at concentration levels in the range 100&ndash, 200 &mu, g/kg. The within-laboratory reproducibility, expressed as a relative standard deviation, was &lt, 15.5%. Decision limits ranged between 100.3 &mu, g/kg and 105.6 &mu, g/kg and the detection capability varied between 100.6 &mu, g/kg and 109.7 &mu, g/kg. Ruggedness was evaluated by following the Youden approach, in terms of milk mass, sorbent mass, centrifugation time, vortex time, type and volume of organic solvents and evaporation temperature.

A confirmatory high pressure liquid chromatographic method for the determination of seven quinolone antibiotics in tissue of Atlantic salmon (Salmo salar L.) was developed. Ciprofloxacin (CIP), danofloxacin (DAN), enrofloxacin (ENR), sarafloxacin (SAR), oxolinic acid (OXO), nalidixic acid (NAL) and flumequine (FLU) were separated on a Perfectsil ODS-2 120 (250 mm × 4 mm, 5 μm) column by gradient elution with a mobile phase consisting of 0.1% trifluoroacetic acid (pH=1), acetonitrile and methanol at 25°C within 22 min. Analytes were monitored at 255 nm (for the determination of OXO, NAL and FLU) and 275 nm (for CIP, DAN, ENR and SAR) by means of photodiode array detector. Examined quinolones were isolated from salmon tissue by extraction with citrate buffer solution (pH=4.7) and purified by solid phase extraction using Oasis HLB (200mg/6 mL) cartridges. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity according to the European Union Decision 2002/657/EC. The accuracy of the method was additionally proved by its application to certified reference material of salmon tissue (BCR® 725).

In the present study, the impregnation of a micro – meso porous activated carbon with magnetite (Fe 3 O 4 ) was successfully achieved by sonication and the magnetic activated carbon prepared (Bmi) was evaluated as a new adsorbent for ultrasonic assisted magnetic solid phase dispersive extraction of Bisphenol A (BPA) from cow milk and human breast milk samples, prior to the determination by HPLC with UV detection. The prepared Bmi was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The effect of pH on adsorption, initial concentration, contact time and desorption were studied. The main experimental parameters influencing extraction efficiency of BPA, such as type and amount of the adsorbent, sample amount, type of desorption solvent, time of adsorption and desorption, type of precipitation solvent, were investigated and optimized. Under the optimal extraction conditions the absolute recovery of BPA was 81% and 95% in cow milk and human breast milk samples, respectively. Good linearity was observed in the investigated concentration range of 2.5 μg kg −1 –5000 μg kg −1 (R 2 = 0.9997). Limit of detection (LOD) was 0.75 μg L −1 , which is in accordance with the specific migration limit (SML) established by the European Union, and limit of quantification (LOQ) was 2.5 μg L −1 . Within-day and between-day recoveries ranged from 91.4% to 98.6% and 89.1% to 99.4% respectively and the RSDs were less than 3.7%. Due to the excellent magnetic behavior of Bmi the proposed method was shown to be simple and rapid. Besides these, this method is sensitive, low cost, efficient and environmentally friendly.

A confirmatory high-pressure liquid chromatographic method for the determination of nine tetracyclines in Sparus aurata (gilthead seabream) muscle tissue is developed and presented herein. Tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline, chlortetracycline, 4-epi-chlortetracycline, doxycycline, methacycline and demeclocycline were separated on a Kromasil, C18 (250 mm × 4 mm, 5 μm) analytical column by gradient elution with a mobile phase consisting of 0.001 M ethylenediaminetetraacetic acid/sodium salt and acetonitrile at 25°C. Diode array detection with monitoring at 280 nm (for the determination of chlortetracycline, 4-epi-chlortetracycline, methacycline and demeclocycline) and 355 nm (for tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline and demeclocycline) was applied for peak identification and quantification of analytes. Examined antibiotics were isolated from gilthead seabream tissue by leaching using a citrate buffer (pH 4.0) and purified by solid phase extraction using Oasis HLB(200 mg/6 mL) cartridges. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity according to the European Union Decision 2002/657/EC.

A novel and simple high-performance liquid chromatography method has been developed for the simultaneous determination of two selective serotonin reuptake inhibitors (fluoxetine and paroxetine) and two serotonin-norepinephrine reuptake inhibitors (venlafaxine and duloxetine) in alternative samples of toxicological interest such as hair, nail clippings, and cerebrospinal fluid (CSF). The separation was achieved on a Hichrom Kromasil 100-5C(18) (250 × 4.6 mm) 5 μm column by using ammonium acetate (0.05 M)-acetonitrile (59:41% v/v) as the mobile phase, delivered isocratically at a flow rate of 1.3 mL/min, within ca. 10 min. Ultraviolet detection at 235 nm was used for monitoring the eluting analytes. Validation was performed in terms of linearity, selectivity, accuracy, precision, and stability. Correlation coefficients were greater than 0.9954. The limits of quantitation ranged between 0.3 and 2.1 ng/μL for all analytes in the liquid matrix (CSF), while the respective values were in the range of 0.3-3.6 ng/mg for solid matrices (hair and nail clippings), with an injection volume of 20 μL. Repeatability and intermediate precision (relative standard deviation, RSD%) were less than 16.6%. The method was successfully applied to actual hair and nail samples from a patient under fluoxetine treatment.

A HPLC method with diode-array detection, at 265 nm, was developed and validated for the determination of ten sulfonamides (SAs): sulfadiazine (SDZ), sulfathiazine (STZ), sulfamethoxine (SMTH), sulfamethizole (SMZ), sulfamethoxypyridazine (SMPZ), sulfamonomethoxine (SMMX), sulfamethoxazole (SMXZ), sulfisoxazole (SIX), sulfadimethoxine (SDMX), and sulfaquinoxaline (SQX) in milk. A mixture of ethyl acetate, n-hexane, and isopropanol was used for the extraction of target analytes from milk. The mobile phase, a mixture of 0.1% v/v formic acid, CH(3) CN, and CH(3) OH was delivered to the analytical column under a gradient program. The procedure was validated according to the European Union regulation 2002/657/EC in terms of selectivity, stability, decision limit, detection capability, accuracy, and precision. Mean recoveries of sulfonamides from milk samples spiked at three concentration levels (0.5×MRL, 1×MRL, and 1.5×MRL) (MRL, maximum residue level) were 93.9-115.9% for SDZ, 97.8-102.9% for STZ, 94.6-107.0% for SMTH, 98.3-111.5% for SMZ, 95.3-108.4% for SMPZ, 97.9-106.0% for SMMX, 97.6-111.3% for SMXZ, 94.3-104.6% for SIX, 96.4-109.1% for SDMX, and 98.2-111.2% for SQX. All RSD values were lower than 8.8%. The decision limits CCa calculated by spiking 20 blank milk samples at MRL (100 μg/kg) ranged from 101.61 to 106.84 μg/kg, whereas the detection capability CCb ranged from 105.64 to 119.01 μg/kg.

The availability of a sensitive and rapid analytical method for the determination of opiates, and other substances of forensic interest, in a variety of biological specimens is of utmost importance to forensic laboratories. Solid-phase extraction is very popular in the pre-treatment of forensic samples. Nevertheless, a new approach, disposable pipette extraction (DPX), is gaining increasing interest in sample preparation. DPX has already been applied to the analysis of drugs of abuse in common biological matrices, such as urine and blood, but has not yet been evaluated on alternative biological samples, such as vitreous humor. The objective of this study was to evaluate the applicability of DPX on the analysis of opiates in vitreous humor. The currently developed method is fast, reliable, and easy to perform. The sensitivity, precision, and accuracy are satisfactory. Recoveries obtained are within the range of 72-91%, whereas the sample volume of vitreous humor required is only 100 μL.

Fast and accurate analysis is a prerequisite in all analytical fields especially in food, biological, pharmaceutical, and environmental samples. The new trend of ultra performance liquid chromatography (LC) has the main drawback of expensive instrumentation, which can't be easily found in low-budget analytical laboratories. The evolution of core shell technology has contributed to this direction, since ultra high efficiency can be achieved on common LC instrument platforms. Herein the novel core shell analytical column, KINETEX ™2.6 µm, (150 mm × 4.6 mm) was comparatively studied against two conventional reversed-phase silica-based and one monolithic column. Eight antimicrobial agents representing two different classes: penicillins and amphenicols, were separated using a typical 400 bar high performance liquid chromatography (HPLC) equipment. Comparison of column performance was carried out by calculation of the number of theoretical plates N, the tailing factor Tf, the relative retention time RRT, the retention factor k, the resolution factor Rs, and the precision of the retention time and peak area. Optimal chromatographic conditions were used to validate the method. Its applicability was proven by the analysis of veterinary drug formulations. The examined antibiotics were well resolved within 17 min. Limit of quantitation values were 25.9 ng for amoxicillin, 14.1 ng for ampicillin, 41.6 ng for thiamphenicol, 9.6 ng for oxacillin, 23.5 ng for florfenicol, 26.7 for cloxacillin, 23.5 ng for chloramphenicol and 42.3 ng for dicloxacillin for 20 µL injection volume. The developed method can be easily and readily transferred to any laboratory. Copyright © 2010 John Wiley & Sons, Ltd.

A reversed phase high performance liquid chromatographic (HPLC) method is developed and validated for the simultaneous determination of anabolic steroids: testosterone (TES), epitestosterone (EPI), and nandrolone (NAN). The analytical column, Inertsil C8, 5 µm, 250 × 4 mm, was operated at ambient temperature. Isocratic elution was performed using a mixture of 50% buffer solution CH3COOH 0.11% –CH3COONa 7.5 mmol/L, pH = 4, 45% CH3CN and 5% CH3OH, at a flow rate of 1.1 mL/min. UV detection was performed at 238 nm. The detection limits of the method were 2.4 ng for NAN, 3.6 ng for TES, and 2.6 ng for EPI in blood plasma, and 2.7 ng for NAN, 1.1 ng for TES, and 3.8 ng for EPI in urine, per 20 µL injection volume. Alprazolam was used as internal standard at a concentration of 2 ng/µL. Validation of the method was performed in terms of accuracy and precision: intra-day assay (n = 6) and inter-day assay (n = 3 × 6) and was found to be satisfactory, with high accuracy and precision results. Sample prepar...

A simple, sensitive, selective, and reproducible RP-HPLC method with DAD detection at 240 nm was developed for the determination of six 1,4-benzodiazepines: bromazepam (BRZ), clonazepam (CLZ), diazepam (DZP), flunitrazepam (FNZ), lorazepam (LRZ), alprazolam (APZ); and two metabolites: alpha-hydroxyalprazolam (HALZ) and alpha-hydroxytriazolam (HTZL) in human plasma, urine, and saliva, using colchicine as internal standard, after SPE using Nexus Varian cartridges. Separation was performed on a Kromasil C(8) (250 mm x 5 mm, 5 microm) analytical column with a gradient mobile phase containing methanol, ACN and 0.05 M ammonium acetate. Linearity was held within the range 0.3-20.0 ng/microL, with coefficients of determination (r(2)) better than 0.997. The within- and between-day assay RSD at 2, 4, 8 ng/microL ranged from 0.03 to 4.7% and 0.5 to 7.0%, respectively in standards, from 1.3 to 7.9% and 3.3 to 7.3%, respectively in plasma, from 2.1 to 6.0% and 2.1 to 7.8%, respectively in urine and at 0.5, 1.0, 2.0 ng/microL ranged from 2.22 to 5.8% and 2.2 to 8.1%, respectively, in saliva. The mean relative recoveries were 96.3-108.6, 96.0-108.2, 94.3-107.1, 97.0-107.0% in within-day assay and 96.8-107.7, 94.6-107.6, 93.2-105.8, 96.0-108.6 in between-day assay for standard, plasma, urine, and saliva, respectively. The LOD and LOQ were 0.02-0.47 and 0.07-1.57 ng/microL, respectively.

An HPLC method with diode array detection, at 355 nm, was developed and validated for the determination of seven tetracyclines (TCs) in bovine and porcine muscle tissues. Examined tetracyclines include: minocycline (MNC), tetracycline (TC), oxytetracycline (OTC), methacycline (MTC), demeclocycline (DMC), chlortetracycline (CTC), and doxycycline (DC). These were extracted from tissues using oxalate buffer (pH 4). Samples were purified by SPE on Nexus cartridges, using MeOH/ACN/0.05 M C2H2O4 (30:30:40 v/v/v) as elution solvent. The separation was achieved on a Kromasil C18, 5 µm, 250 × 4 mm, analytical column, operating at ambient temperature. The mobile phase, a mixture of A: 0.01 M oxalic acid and B: CH3CN, was delivered using a gradient program. The procedure was validated according to the Decision 2002/657/EC, by determining selectivity, stability, decision limit, detection capability, accuracy, and precision. Overall recoveries of TCs from bovine and porcine samples ranged from 89–114.1%. All ...

The widespread use of antibiotics in veterinary medicine for prophylactic, therapeutic and growth promoting purposes may result in the presence of residues in foodstuff of animal origin. Sulfonamides, N‐derivatives of 4‐amino‐benzenesulfonamide, belong to a diverse class of synthetic antibiotics consisting of chemically related compounds. A number of them e.g., sulfamethazine, sulfadiazine, sulfaquinoxaline and sulfamethoxypyridazine, are widely used in animal husbandry. Their residues in food are of great concern because of their potential carcinogenic character and because they may contribute to the development of antibiotic resistance in humans. These facts have induced most of the regulatory activities on sulfonamides. Regulatory bodies in the European Union as well as in other countries have set different maximum residue limits in various tissues. These regulations have stimulated the development of fast, accurate and sensitive analytical methods for monitoring sulfonamide residues in food samples of...

Herein an HPLC method with diode array detection, at 355 nm, is described for the determination of seven tetracyclines in liver and kidney muscle tissues: minocycline, tetracycline, oxytetracycline, methacycline, demeclocycline, chlortetracycline, and doxycycline. The examined TCs were extracted from both tissues with 20% TFA and 0.4 M oxalate buffer (pH 4). For further purification of liver and kidney tissues Discovery and LiChrolut SPE cartridges were used, respectively, with 0.01 M C2H2O4/CH3CN/CH3OH (40:30:30 v/v/v) as elution solvent. The separation was achieved on a Kromasil ODS-3, 5 µm, 250 × 4 mm, analytical column. The mobile phase, a mixture of 0.01 M oxalic acid and CH3CN, was delivered using a gradient program. The procedure was validated according to the Decision 2002/657/EC, determining selectivity, stability, decision limit, detection capability, accuracy, and precision. Overall recoveries ranged from 93.2–125.5% and 81.3–120.4% for liver and kidney tissues, respectively. All RSD v...

Herein, an HPLC method with diode-array detection, at 355 nm, is described for the determination of seven tetracyclines in chicken muscle and egg yolk: minocycline, tetracycline, oxytetracycline, methacycline, demeclocycline, chlortetracycline, and doxycycline. The examined TCs were extracted from chicken muscle with 15% TFA and 0.4 M oxalate buffer (pH 4) and from egg yolk with 40% TFA and 0.4 M oxalate buffer (pH 4). LiChrolut and Nexus SPE cartridges were used for further purification of chicken tissue and egg yolk extracts, respectively, with 0.01 M C2H2O4/CH3CN/CH3OH (40:30:30 v/v/v) as elution solvent. The separation was achieved on a Kromasil ODS-3, 5 µm, 250 × 4 mm, analytical column. The mobile phase, a mixture of 0.01 M oxalic acid and CH3CN, was delivered using a gradient program. The procedure was validated according to the Decision 2002/657/EC, determining selectivity, stability, decision limit, detection capability, accuracy, and precision. Overall recoveries ranged from 92–110.1% a...

The issue of antimicrobial use in animals used as food is of global concern. Antimicrobials are used in animal agriculture to improve health and welfare of animals, meat quality, the economic efficiency of growth and production and public health by decreasing shedding of zoonotic pathogens. However, large quantities are often used without professional supervision. The growth-promotant (now reclassified as zootechnical feed additives) effect of low levels of antibiotics in animal feeds was first described in the late 1940s. Already in 1969 the Swann Committee recommended that use of antibiotics as a supplement in animal feedstuff should be restricted to those with little or no application as therapeutic agents for humans and animals, which would not impair the efficacy of therapeutic antibiotics through the development of resistant strains of organisms. Antimicrobials like avoparcin, ardacin, zinc bacitracin, virginiamycin, tylosin, spriramycin, carbadox and olaquindox were withdrawn within the period 1997-1999. Four others (monensin sodium, salinomycin sodium, avilamycin and flavophospholipol) were still permitted for use as growth promoters in animal feed to animals marketed in the European Union (EU). Since January 2006, they have been banned as well. This review focuses on the analytical methods developed to be an effective tool for monitoring compliance with the ban.

In the present study, an HPLC method was developed and validated for the determination of four sulphonamides: sulphadiazine (SDZ), sulphaquinoxaline (SQX), suplhamethazine (SMTH), and sulphadimethoxine (SDM). Two of them, SQX and SDM, were determined in cow's milk. The analytical column, a Kromasil, C18 5 µm, 250×4 mm analytical column, was operated at ambient temperature. The mobile phase, a mixture of 0.5% acetic acid as solvent A, CH3CN as solvent B, and CH3OH was delivered to the analytical column according to a gradient program. PDA detection was performed for the detection and confirmation of separated analytes with monitoring at 260 nm. Method validation was performed by means of intra‐day (n=5) and inter‐day accuracy and precision (n=5), sensitivity, and linearity. Limits of detection (LOD) and limits of quantification (LOQ) were 13 and 40 µg/kg, respectively. Solid phase extraction was applied to remove all matrix interference from milk samples after deproteinization with 8 M HCl. High e...

A sensitive multi-residue analytical method was developed for the determination of ten quinolones: enoxacin, ofloxacin, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine in bovine liver and porcine kidney. A simple liquid extraction step followed by a solid phase extraction clean up procedure was applied for the extraction of quinolones from liver and kidney tissues. Recoveries of the extraction varied between 82 and 88% for bovine liver and 92 and 95% for porcine kidney. Separation was performed on an ODS-3 PerfectSil Target (250 x 4 mm) 5 microm analytical column at 25 degrees C. The mobile phase consisted of a mixture of TFA 0.1%-CH(3)CN-CH(3)OH, delivered at a flow rate of 1.2 mL/min according to a gradient program. Elution of quinolones and the internal standard (caffeine, 7.5 ng/microL) was complete within 27 min. Photodiode array detection was used for monitoring the eluants at 275 and 255 nm. The method was fully validated according to the European Union Decision 2002/657/EC, determining linearity, selectivity, decision limit, detection capability, accuracy, and precision. The LODs of the specific method of quinolone determination in bovine liver varied between 3 and 7 microg/kg and in porcine kidney between 3 and 4 microg/kg.

Fabric phase sorptive extraction (FPSE), a novel sorbent-based microextraction method, was evaluated as a simple and rapid strategy for the extraction of four penicillin antibiotic residues (benzylpenicillin, cloxacillin, dicloxacillin and oxacillin) from cows' milk, without prior protein precipitation. Time-consuming solvent evaporation and reconstitution steps were eliminated successfully from the sample preparation workflow. FPSE utilizes a flexible fabric substrate, chemically coated with sol-gel derived, highly efficient, organic-inorganic hybrid sorbent as the extraction medium. Herein short-chain poly(ethylene glycol) provided optimum extraction sensitivity for the selected penicillins, which were analysed using an RP-HPLC method, validated according to the European Decision 657/2002/EC. The limit of quantitation was 10μg/kg for benzylpenicillin, 20μg/kg for cloxacillin, 25μg/kg dicloxacillin and 30μg/kg oxacillin. These are a similar order of magnitude with those reported in the literature and (with the exception of benzylpenicillin) are less than the maximum residue limits (MRL) set by European legislation.

An HPLC method with diode-array detection, at 355 nm, was developed and validated for the determination of seven tetracyclines (TCs) in milk: minocycline (MNC), TC, oxytetracycline (OTC), methacycline (MTC), demeclocycline (DMC), chlortetracycline (CTC), and doxycycline (DC). Oxalate buffer (pH 4) was used with 20% TCA as a deproteinization agent for the extraction of analytes from milk followed by SPE. The separation was achieved on an Inertsil ODS-3, 5 microm, 250 x 4 mm(2 )analytical column at ambient temperature. The mobile phase, a mixture of A: 0.01 M oxalic acid and B: CH(3)CN, was delivered using a gradient program. The procedure was validated according to the European Union decision 2002/657/EC determining selectivity, stability, decision limit, detection capability, accuracy, and precision. Mean recoveries of TCs from spiked milk samples (50, 100, and 200 ng/g) were 93.8-100.9% for MNC, 96.8-103.7% for OTC, 96.3-101.8% for TC, 99.4-107.2% for DMC, 99.4-102.9% for CTC, 96.3-102.7% for MTC, and 94.6-102.1% for DC. All RSD values were lower than 8.5%. The decision limits CC(a) calculated by spiking 20 blank milk samples at MRL (100 microg/kg) ranged from 101.25 to 105.84 microg/kg, while detection capability CC(b )from 103.94 to 108.88 microg/kg.

The aim of this work was to develop an HPLC method for the simultaneous determination of ten quinolones: enoxacin, ofloxacin, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, oxolinic acid, nalidixic acid, and flumequine, in various tissues of food-producing animals. Separation was achieved on a PerfectSil Target column (250 mm x 4 mm, ODS-3, 5 microm), by MZ-Analysentechnik (Germany), at room temperature. The mobile phase consisted of 0.1% TFA-CH(3)OH-CH(3)CN and was delivered by a gradient program of 35 min. The detection and quantitation was performed on a photodiode array detector at 275 and 255 nm. Caffeine (7.5 ng/microL) was used as the internal standard (IS). Analytes were isolated from tissue samples by 0.1% methanolic TFA solution. SPE, using LiChrolut RP-18 cartridges, was applied for further purification. The extraction protocol was optimized and the final recoveries varied between 92.0 and 107.4%. The method was fully validated according to Commission Decision 2002/657/EC. Limits of quantitation for the examined quinolones extracted from each tissue were much lower than the respective Maximum Residue Levels, ranging between 30 and 50 microg/kg for bovine tissue, between 30 and 55 microg/kg for ovine tissue, and between 40 and 50 microg/kg for porcine tissue.

An HPLC method was developed and validated for the determination of the cephalosporins cefotaxime and cephalexine in skimmed bovine milk. The analytical column, Kromasil C18 (250 mm × 4.0 mm, 5 µm) was operated at ambient temperature. Mobile phase consisted of CH3OH-acetate buffer (pH = 4.0) and it was delivered isocratically at a flow rate of 1.0 mL · min−1. Total analysis time was less than 5 min. Caffeine was used as internal standard (5 ng · µL−1). UV detection was performed at 265 nm. Method validation was performed by means of intra-day (n = 5) and inter-day accuracy and precision (n = 8), sensitivity and linearity. Limits of detection (LOD) and limits of quantification (LOQ) were 0.1 and 0.3 ng · µL−1, respectively. The method was applied to the analysis of a veterinary drug (CEPOREX) containing cephalexine. The results were quite accurate with the relative error varying from −8.0 to −3.5%. Solid-phase extraction was applied to remove all matrix interference from milk samples. High extraction recoveries (average 84–121%) were achieved by using Abselut NEXUS cartridges with acetonitrile as eluent and a rinsing step with water and n-butanol. A pre-concentration step was necessary in a 1/10 level to reach the EU MRL concentration level (100 µg · kg−1). RSD values were less than 7% for both cephalosporins.

A reversed‐phase high performance liquid chromatographic (HPLC) method is developed and validated for the simultaneous determination of anabolic steroids: testosterone and its major metabolite, epitestosterone. The analytical column, Inertsil ODS‐2, 5 µm, 250×4 mm, was operated at ambient temperature. Isocratic elution was performed using 35% of A=buffer solution 0.11% CH3COOH‐CH3COONa 7.5 mmol/L, pH=4 and 65% of B=CH3CN, at a flow rate of 0.8 mL/min. Inlet pressure was 155 bar. UV detection was performed at 236 nm. The limit of detection was 0.02 ng per 20 µL injection volume, while linearity held up to 2 ng/µL. p‐Cresol was used as internal standard at a concentration of 2 ng/µL. Validation of the method was performed in terms of accuracy and precision: intra‐day assay (n=6) and inter‐day assay (n=3×5) and was found to be satisfactory, with high accuracy and precision results. The method was successfully applied to biological fluids after solid phase extraction (SPE) on Nexus cartridges. Recove...

Fabric phase sorptive extraction (FPSE) is a novel sample preparation technique which utilizes advanced material properties of sol-gel derived microextraction sorbents and the hydrophilic property of the cellulose fabric substrate, resulting in a highly sensitive and fast microextraction device, capable of extracting target analyte(s) from any complex aqueous sample matrices. Due to the low organic solvent consumption, FPSE meets all green analytical chemistry (GAC) criteria. This technique was applied, for the first time, for the determination of sulfonamides residues in milk using a highly polar sol-gel poly(ethylene glycol) (sol-gel PEG) coated FPSE media. The developed HPLC method was validated according to the European Union Decision 2002/657/EC. Decision limit (CCα) values were 116.5 μg kg(-1) for sulfamethazine, 114.4 μg kg(-1) for sulfisoxazole and 94.7 μg kg(-1) for sulfadimethoxine, whereas the corresponding results for detection capability (CCβ) were 120.4 μg kg(-1) for sulfamethazine, 118.5 μg kg(-1) for sulfisoxazole and 104.1 μg kg(-1) for sulfadimethoxine.

A quantitative method for the determination of four penicillin antibiotics, amoxicillin (AMO), oxacillin (OXA), cloxacillin (CLO), and dicloxacillin (DICLO), has been developed. Separation was achieved on an Inertsil ODS-3 (250 x 4 mm, 5 microm) column after selective extraction of penicillin drugs from biological matrices by means of SPE. Gradient elution with a mobile phase consisting of 0.1% TFA (pH 1) and ACN, and PDA detection with monitoring at 240 nm was applied. Salicylic acid (5 ng/microL) was used as the internal standard. RP-8 Adsorbex Merck cartridges provided high absolute recoveries (98-101%). The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 8) and between-day precision (n = 8) revealed RSD

A novel sorbent material of ultrapure silica gel provided with novel State of the Art Bonding- and Endcapping Technology commercially available under the name PerfectSil Target (250 x 4 mm, ODS-3, 5 microm, by MZ-Analysentechnik, Germany) was used and validated for the sensitive HPLC determination of ten quinolone antibiotics: enoxacin, ofloxacin, norfloxacin, ciprofloxacin, danofloxacin (DAN), enrofloxacin (ENR), sarafloxacin, oxolinic acid (OXO), nalidixic acid (NAL), and flumequine. The analytical column validation was performed in terms of separation efficiency, precision, and peak asymmetry. The separation was achieved at ambient temperature using a mobile phase of TFA (0.1%)-CH3OH-CH3CN delivered under the optimum gradient program, at a flow rate of 1.2 mU/min. Photodiode array detection was used and eluant was monitored at 275 nm. For the quantitative determination caffeine (7.5 ng/microL) was used as internal standard. The achieved LODs were 0.03 ng/microL per 50 microL injected volume for OXO, 0.1 ng/microL for DAN, ENR, and NAL, and 0.2 ng/microL for the remaining six studied quinolones. The method was validated in terms of interday (n = 6) and intraday (n = 5) precision and accuracy. The proposed method was successfully applied to the analysis of pharmaceutical formulations destined either for human or for veterinary use.

A simple and rapid reversed‐phase high performance liquid chromatographic (RP‐HPLC) method was developed for the routine determination of quinine in soft drinks, which is added when a bitter taste is required. The analytical column, an MZ Kromasil, C18, 5 µm, 250 × 4 mm2, was operated at ambient temperature with backpressure of 230 kg/cm2. The mobile phase consisted of CH3OH–CH3CN–CH3COONH4 0.1 M, (45:15:40 %v/v/v) and was delivered at a flow rate of 1.0 mL/min. Fluorescence detection was performed at 325 nm (excitation) and 375 nm (emission). For the quantitative determination of quinine, salicylic acid was used as internal standard at a concentration of 0.5 ng/µL, resulting in a detection limit (signal‐to‐noise ratio 3:1) of 0.3 ng, while the upper limit of linear range was 0.7 ng/µL. Analysis time was less than 5 min. The statistical evaluation of the method was examined performing intra‐day (n = 8) and inter‐day calibration (n = 8) and was found to be satisfactory, with high accuracy and prec...

A simple, sensitive, reliable, and fast analytical method was developed for the simultaneous determination of amphenicols residues in raw milk by combining fabric phase sorptive extraction (FPSE) and high-performance liquid chromatography-diode array detection. FPSE, a new generation green sample preparation technique, efficiently incorporates the advanced and tunable material properties of sol–gel derived microextraction sorbents with the rich surface chemistry of a cellulose fabric substrate, resulting in a flexible, highly sensitive, and fast microextraction device capable of extracting target analytes directly from complicated sample matrices. Due to the strong chemical bonding between the sol–gel sorbent and substrate, the microextraction device demonstrates a very high chemical and solvent stability. Therefore, any organic solvent/solvent mixture can be used as the eluent/back-extraction solvent. Herein, a highly polar polymer coated FPSE media was created using short-chain poly(ethylene glycol) (PEG) and the applicability of this novel microextraction device to extract highly polar amphenicol antibiotics from raw milk was investigated. Due to the intense affinity of amphenicols towards the strongly polar sol–gel PEG-coated FPSE device, absolute recovery of the selected antibiotics residues were found to be 44% for thiamphenicol, 66.4% for florfenicol, and 81.4% for chloramphenicol. The developed method was validated in terms of sensitivity, linearity, accuracy, precision, and selectivity according to European Decision 657/2002/EC. Decision limit (CCα) values were 52.49 μg kg−1 for thiamphenicol, 55.23 μg kg−1 for florfenicol, and 53.8 μg kg−1 for chloramphenicol, while the corresponding results for detection capability (CCβ) were 56.8 μg kg−1, 58.99 μg kg−1, and 55.9 μg kg−1, respectively.

An improved high performance liquid chromatographic-photodiode array method, using a multi-linear gradient elution, is described for the simultaneous determination of caffeine and its eight primary metabolites: xanthine (XA), 7-methylxanthine (7-MX), 3-methylxanthine (3-MX), 1-methylxanthine (1-MX), isocaffeine (IC), theobromine (TB), paraxanthine (PA) and theophylline (TP). The separation method Is based on mobile phase optimization and off-line solid-phase extraction (SPE) from human biological fluids: blood serum and urine. The eluting system consisted of ammonium acetate 0.05 M (pH=7) and methanol (90:10 v/v) changing to (40:60 v/v) over a period of 30 min. Identification of metabolites was achieved by photodiode array detector at 270 nm resulting in 2 ng limit of detection, while linearity held up to 20 ng/μL for each compound. Lamotrigine was used as internal standard at a concentration of 10.0 ng/μL. The statistical evaluation of the method was examined performing intra-day (n=8) and inter-day (n=8...

A rapid, accurate and sensitive method has been developed for the quantitative determination of ciprofloxacin, a new second-generation quinolone carboxylic acid antimicrobial agent, with high in vitro activity against a wide range of Gram- negative pathogens and Gram-positive cocci. A Lichrosorb RP-18 250 x 4.0 mm, 5 μm analytical column was used with an eluting system consisting of a mixture of CH3CN-CH3OH-Citric acid 0.4 M (1:3:6 v/v). Detection was performed with a variable wavelength UV-visible detector at 275 nm resulting in a limit of detection of 0.2 ng per 20 μl injection. For the quantitative determination theophylline was used as chromatographic internal standard at a concentration of 1.56 ng/μl. A rectilinear relationship was observed up to 20 ng/μl. Analysis time was less than 6 min. The statistical evaluation of the method was examined performing intra-day (n=8) and inter-day calibration (n=8) and was found to be satisfactory with highly accurate and precise results. The method was a...

According to the International Conference on Harmonization (ICH), “any component of the drug product that is not the chemical entity defined as the drug substance or an excipient in the drug product” is considered as impurity. Impurities can arise from various steps during synthesis, manufacture, storage or transportation. The great importance of their detection, structure elucidation and quantitation is beyond any doubt, since they may cause various health problems. Their presence even in small quantities may give rise to safety, efficacy, purity, stability as well as quality issues. For this reason, regulatory authorities such as ICH, the United States Food and Drug administration (FDA), different Pharmacopoeias like British Pharmacopoeia, have set guidelines regarding their profiling in pharmaceutical formulations.

Ion Chromatography is a well-established analytical technique for the simultaneous determination of ions. This paper focuses on the analytical determination of eight inorganic anions: fluoride, hydrogen carbonate, chloride, nitrite, bromide, nitrate, hydrogen phosphate and sulphate, using conductometric detection. The separation of the cited anions was achieved on a low capacity anion exchange column Hamilton PRP-X100 100 × 4.1 mm, 10 μm, with a mobile phase consisted of 2.5 mM p-hydroxybezoic acid and 2.0 mM sodium benzoate at a pH 9.0 adjusted with 1N NaOH and 8% Ch3OH as organic modifier, at a flow rate 0.7 ml/min. For the quantitative determination bromide was used as internal standard at a concentration of 7.8 mg/l. A rectilinear relationship was observed up to 40 mg/l for all ions except for carbonate that was up to 30 mg/l. The detection limits (S/N = 3) were 100 μg/l for carbonate and 50 μg/l for the rest of the cited anions, when 50 μ/l of the samples were injected onto the analytical co...

Background: Disposable pipette extraction with reversed-phase sorbent is proposed for the fast and simple GC determination of the antipsychotic drugs chlorpromazine, olanzapine, clozapine and biperiden – an anticholinergic drug – in human urine. The method was validated and successfully applied to postmortem urine samples. The analytical run was 11 min and lidocaine was used as the internal standard. Results: The developed method showed good linearity, over the range of 0.34 to 5 ng/µl, for all compounds. The within-day and between-day precision and accuracy assays revealed values ≤15%, while the recoveries ranged from 85 to 120%. LOD and LOQ ranged from 0.28 to 0.42 ng/µl and from 0.85 to 3.58 ng/µl, respectively. Conclusion: The developed method is a user-friendly technique, which is simple and fast.

Background: Risperidone, quetiapine, amisulpride and aripiprazole are atypical antipsychotics increasingly prescribed in Greece. Results: We have developed and validated a UHPLC–diode array detector method for the determination of these drugs in whole blood, urine and cerebrospinal fluid, following SPE. The separation was achieved within 7 min. Validation was performed in terms of linearity, selectivity, accuracy, precision and stability. Following validation, the method was applied to post-mortem blood, urine and cerebrospinal fluid samples. Conclusion: The method proved fast and simple for the determination of four atypical antipsychotic drugs in whole blood, urine and cerebrospinal fluid. To the best of our knowledge, this is the only available method for the simultaneous determination of these drugs in cerebrospinal fluid.

The application of ultrasound-assisted matrix solid phase dispersive extraction for the confirmatory analysis of 12 β-lactam antibiotics in milk by high performance liquid chromatography with photodiode array detection has been proposed herein. Four penicillins (cloxacillin, dicloxacillin, oxacillin, and amoxicillin) and eight cephalosporins (cefaclor, cefadroxil, ceftiofur, cefuroxime, cefoperazone, cefazolin, cephalexin, and cefotaxime) are effectively extracted using a mixed sorbent of Quick Easy Cheap Effective Rugged Safe technique and OASIS HLB providing a matrix free from any endogenous interference. Examined analytes were well resolved on an Inertsil ODS-3 analytical column with a mobile phase of CH(3)COONH(4) (0.05 M) and acetonitrile delivered under a gradient program. 1,7-Dimethyl-xanthine was used as internal standard. The method was validated meeting the European Legislation determining linearity, selectivity, stability, decision limit, detection capability, accuracy, precision, and ruggedness according to the Youden approach. Recoveries of all antibiotics rated from 85.0 to 115.7%, while RSD values were

An isocratic Reversed - Phase High Performance Liquid Chromatographic (RP -HPLC) method is presented for the simultaneous determination of atropine sulphate and scopolamine-N-butylbromide. The analytes were separated on a Brownlee RP-18, Spheri-5, 220 × 4.6mm I.D. column with a mobile phase consisting of 0.05M ammonium acetate - methanol-acetonitrile (48:32:20 v/v). Flufenamic acid was used as internal standard and the analysis was completed within approximately 10 rnin. The detection was performed with a variable wavelength UV - visible detector at 220 nm resulting in detection limits of 18 ng of each alkaloid per 10 μl injection. The peak area ratios of each analyte relative to internal standard showed a linear relationship with concentrations between 1.81 - 90.4 ng/μl for atropine sulphate and 1.87 - 104 ng/μl for scopolamine-N-butylbromide. The average relative standard deviation for injection reproducibility was approximately 2%. The method was applied to the direct determination of scopolam...

A confirmatory high performance liquid chromatography method for the determination of six penicillin antibiotics and three amphenicol antibiotics in gilthead seabream (Sparus Aurata) tissue was developed. Ampicillin (AMP), penicillin G (PG), penicillin V (PV), oxacillin (OXA), cloxacillin (CLO), dicloxacillin (DICLO), thiamphenicol (TAP), florfenicol (FFC) and chloramphenicol (CAP) were separated on an Inertsil, C(8) (250×4 mm, 5 μm) column by gradient elution with a mobile phase consisting of ammonium acetate 0.05 M and acetonitrile at 25°C. Diode array detection with monitoring at 225 nm (for the determination of AMP, PG, PV, TAP and FFC), 240 nm (for OXA, CLO and DICLO) and 278 nm (for CAP) was applied. Examined antibiotics were isolated from gilthead seabream tissue by liquid-liquid extraction and further clean-up was performed by solid phase extraction using Oasis HLB (200 mg/6 mL) cartridges. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity according to the European Union Decision 2002/657/EC.

Venlafaxine is a very popular antidepressant in Greece. There is an increasing rate of self-poisoning cases with this drug presenting at the emergency departments around the country. We have developed a simple HPLC method with ultraviolet detection for the simultaneous determination of venlafaxine and its major metabolite, O-desmethylvenlafaxine, in human serum following solid-phase extraction. The developed method was validated in terms of sensitivity, linearity, accuracy, precision, stability and selectivity both for therapeutic and toxic serum ranges, and was applied to human serum samples. The method currently developed and validated is simple, does not require expensive instrumentation and can therefore be easily applied in the clinical toxicology setting for the diagnosis and management of acute venlafaxine intoxication.

Blood serum samples of patients undergoing theophylline therapy were analysed in parallel with a new RP-HPLC method and the therapeutic drug monitoring TDx system. Both techniques are accurate, precise, technically easy, rapid, but the results taken by the TDx method are in all cases higher than HPLC. The mean increase is of about 56%.