An analytical procedure for the determination of different therapeutic drugs in surface waters

2009 ◽  
Vol 60 (2) ◽  
pp. 449-458 ◽  
Author(s):  
Irena Baranowska ◽  
Bartosz Kowalski
Keyword(s):  
Analytical Procedure ◽  
Solid Phase ◽  
Beta Blockers ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Therapeutic Drugs ◽  
Array Detectors ◽  
Oasis Hlb ◽  
Spe Method

An analytical procedure for the determination of 10 drugs belonging to three different therapeutic groups was analysed. Several compounds were investigated which comprise of beta-blockers: sotalol (SOT), metoprolol (MET), propranolol (PRO), carvedilol (CAR); corticosteroids: prednisolone (PRE), dexamethasone (DEX); analgesic, non-steroidal anti-inflammatory (NSAID): paracetamol (PAR), metamizole (MTZ), aspirin (ASP) and ketoprofen (KET). Reversed-phase liquid chromatography with gradient elution, fluorescence (FL) and diode array detectors (DAD) was applied for the selective investigation of the drugs. Three solvents were used as the mobile phase: methanol, 0.05% trifluoroacetic acid (TFA) in water and acetonitrile. The solid phase extraction (SPE) method using the Oasis HLB column was proposed for the preconcentration step. The recovery level for most of the drugs was above 80%. The low values of limits of detection (LOD) for PAR, SOT, MTZ, MET, SAL, PRO, PRE, CAR, DEX and KET were achieved: 106 ng L−1, 1,048 ng L−1, 2.48 ng L−1, 2.17 ng L−1, 16.5 ng L−1, 1.10 ng L−1, 160 ng L−1, 6.62 ng L−1, 76.5 ng L−1 and 45.2 ng L−1, respectively. The suggested method was used for the determination of drugs in spiked surface water.

scholarly journals Development of a Solid-Phase Extraction Method for Determination of Pheophorbide a and Pyropheophorbide a in Health Foods by Liquid Chromatography

2004 ◽  
Vol 87 (4) ◽  
pp. 937-942 ◽  
Author(s):  
Harumi Oshima ◽  
Eiji Ueno ◽  
Isao Saito ◽  
Hiroshi Matsumoto
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Official Method ◽  
Phase Extraction ◽  
Pheophorbide A ◽  
Significant Difference ◽  
Spe Method

Abstract A simple solid-phase extraction (SPE) method was developed for the liquid chromatography (LC) determination of pheophorbide (Phor) a and pyropheophorbide (Pyro) a in health foods such as chlorella, spirulina, etc. The food sample was extracted with 85% (v/v) acetone. The extract was acidified with hydrochloric acid and loaded on a C18 cartridge. After washing with water, Phor a and Pyro a were eluted with the LC mobile phase. Phor a and Pyro a were separated by isocratic reversed-phase LC and quantitated by fluorescence detection. The recoveries for spiked samples of chlorella and the extract were 87.1–102.0%. Commercial health foods (chlorella, spirulina, aloe, kale, Jews mallow, and green tea leaves) were analyzed using the SPE method. The values found for Phor a and Pyro a ranged from 2 to 788 μg/g and from <1 to 24 μg/g, respectively. There was no significant difference between the SPE method and the official method in Japan (spectrophotometry after liquid–liquid extraction). The advantages of the SPE method are the short extraction times, lack of emulsions, and reduced consumption of organic solvents compared with the official method in Japan. The SPE method is considered to be useful for the screening of Phor a and Pyro a in health foods.

scholarly journals UPLC-MS/MS method for determination of retinol and α-tocopherol in serum using a simple sample pretreatment and UniSpray as ionization technique to reduce matrix effects

2020 ◽  
Vol 58 (5) ◽  
pp. 769-779 ◽  
Author(s):  
Nele Peersman ◽  
Jan Van Elslande ◽  
Yannick Lepage ◽  
Samira De Amicis ◽  
Koenraad Desmet ◽  
...  
Keyword(s):  
Matrix Effects ◽  
Solid Phase ◽  
Sample Pretreatment ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Single Step ◽  
Limit Of Quantification ◽  
Phase Gradient ◽  
Ionization Technique

AbstractBackgroundOur goal was to develop a simple, rapid and precise ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of retinol and α-tocopherol in serum. Currently published LC-MS/MS methods either require complex extraction procedures (liquid-liquid or solid-phase) or do not meet desirable specifications for imprecision in serum (coefficient of variation [CV] <6.8% and 6.9%, respectively).MethodsSample preparation consisted of a simple protein precipitation with ethanol and acetonitrile. Stable isotope-labeled internal standards (IS) and a homemade calibration curve were used for quantification. The analysis was performed using an Acquity I-class Xevo TQ XS LC-MS/MS. Chromatographic runtime was 6.0 min using a reversed phase gradient elution. UniSpray (US) as an ionization technique was compared to electrospray ionization (ESI). Analytical validation included matrix effect, recovery and trueness compared to National Institute of Standards and Technology (NIST) standards and United Kingdom National External Quality Assessment Service (UK NEQAS) samples.ResultsIntra- and inter-run CVs were <4.9% for retinol and <1.7% for α-tocopherol, both complying with desirable specifications for imprecision. Bias compared to NIST standards was <3.1% for both compounds. The method was linear over the entire tested range. The lower limit of quantification (LLOQ) with US was lower than with ESI for both retinol (0.022 vs. 0.043 mg/L) and α-tocopherol (0.22 vs. 0.87 mg/L). Matrix effects were not significant (<15%) for retinol. However, for α-tocopherol matrix effects of on average 54.0% were noted using ESI, but not with US.ConclusionsWe developed a fast, precise and accurate UPLC-MS/MS method for the determination of retinol and α-tocopherol in human serum using a single-step sample pretreatment. Ionization using US eliminated the matrix effects for α-tocopherol.

scholarly journals Determination of Chlorotetracycline and Doxycycline in Medicated Feedingstuffs by Liquid Chromatography

2012 ◽  
Vol 56 (3) ◽  
pp. 329-333 ◽  
Author(s):  
Ewelina Patyra ◽  
Ewelina Kowalczyk ◽  
Krzysztof Kwiatek
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Analytical Procedure ◽  
Solid Phase ◽  
Gradient Elution ◽  
Diode Array ◽  
Chromatography Method ◽  
Array Detection ◽  
Liquid Chromatography Method

Abstract High performance liquid chromatography method with diode array detection (HPLC-DAD) was developed and optimised for the determination of tetracyclines (TCs) in medicated feedingstuffs. The extraction of the analyte from feedingstuffs was performed with Na2EDTA-McIlvaine buffer (pH 2.5 and pH 4). The extracts were cleaned up by solid phase extraction using octadecyl cartridges (C18). The samples were dried up and redissolved in the mixture of oxalic acid and methanol. Separation was performed on reserved phase column (Phenomenex C18, 250 x 4.6 mm, 5 μm) by multistep gradient elution, which provided better chromatographic separation. The analysis was performed at a wavelength of 390 nm. Validation study of the method revealed that all obtained calibration curves showed good linearity R= 0.9985 for doxycycline (DC) and R= 0.9981 for chlorotetracycline (CTC) over the range of 25-2,000 mg/kg. The analytical procedure was successfully adapted for quantitative determination of DC and CTC in medicated feedingstuff samples. Validation included determination of specificity, linearity, and repeatability. Mean recovery for spiked samples was 93.1% for CTC and 93.2% for DC. The results of validation of the analytical procedure proved that presented method is efficient, precise and useful for quantification of DC and CTC in medicated feedingstuffs.

scholarly journals Screening method for the determination of selected tetracyclines in water by liquid chromatography with diode array detector

2014 ◽  
Vol 58 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Ewelina Patyra ◽  
Ewelina Kowalczyk ◽  
Krzysztof Kwiatek
Keyword(s):  
Oxalic Acid ◽  
Water Samples ◽  
Solid Phase ◽  
Screening Method ◽  
Gradient Elution ◽  
Environmental Water ◽  
Array Detector ◽  
Chromatographic Procedure ◽  
Oasis Hlb

Abstract A chromatographic procedure for determination of oxytetracycline (OXT), tetracycline (TC), chlorotetracycline (CTC), and doxycycline (DC) in water samples was developed and was applied for the analysis of water samples collected from poultry and pig farms and environmental water samples. Samples were acidified with trifluoroacetetic acid to pH 3 and further purified by solid phase extraction using Oasis HLB cartridges. The samples were dried up and redissolved in the mixture of oxalic acid and methanol. Separation was performed on reserved phase column (Phenomenex column C18 , 250 mm × 4.6 mm, 5 μm) by multistep gradient elution, and detection was carried out at 360 nm for OTC and TC, 370 nm for CTC, and 350 nm for DC. The tetracyclines were eluted with the mobile phase of 0.05 M oxalic acid (pH 2.5), acetonitrile, and methanol. This method provided average recoveries of 83.53% to 108.59%, with coefficient of variations (CVs) of 2.41% to 8.64% in the range of 10 to 1000 μg/L OTC, TC, CTC, and DC in water. The linearity for the tetracyclines was determined by HPLC-DAD in the range 10 to 1000 μg/L, with the correlation coefficient (R) > 0.99. The LOD and LOQ for the tetracyclines in water samples ranged from 1.51 to 4.00 and 2.51 to 5.93 μg/L, respectively.

scholarly journals Determination of Tranquilizers in Swine Urine by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3215 ◽  
Author(s):  
Yingyu Wang ◽  
Xiaowei Li ◽  
Yuebin Ke ◽  
Chengfei Wang ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
Solid Phase ◽  
Multiple Reaction Monitoring ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Single Step ◽  
Swine Urine ◽  
Relative Standard ◽  
Positive Mode

A rapid, reliable, and sensitive method was developed for the determination of ten tranquilizers in swine urine. Sample preparation was based on solid-phase extraction, which combined isolation of the compounds and sample cleanup in a single step. Separation was performed on a reversed phase C18 column by gradient elution with a chromatographic run time of seven minutes, consisting of 0.1% formic acid in water and acetonitrile as the mobile phase. Multiple reaction monitoring in positive mode was applied for data acquisition. Matrix-matched calibration was used for quantification and good linearity was obtained with coefficients of determination higher than 0.99. The average recoveries of fortified samples at concentrations between 0.05 and 10 µg/L ranged from 85% to 106% with interday relative standard deviations of less than 13% in all cases. The limits of detection and limits of quantification obtained for tranquilizers in the urine were in the ranges of 0.03–0.1 µg/L and 0.05–0.25 µg/L, respectively. The applicability of the proposed method was demonstrated by analyzing real samples; diazepam was detected at concentrations between 0.3 and 0.6 μg/L.

scholarly journals Determination of Benzoylurea Insecticides in Apples and Pears by Solid-Phase Extraction Cleanup and Liquid Chromatography with UV Detection

1999 ◽  
Vol 82 (1) ◽  
pp. 213-216 ◽  
Author(s):  
Nicholas G Tsiropoulos ◽  
Pipina G Aplada-Sarlis ◽  
George E Miliadis
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Relative Standard ◽  
Benzoylurea Insecticides ◽  
Preliminary Extraction ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed and statistically validated for simultaneous determination of 5 benzoylurea insecticides (di-flubenzuron, triflumuron, teflubenzuron, flufenoxuron, and lufenuron) in apples and pears. It involves preliminary extraction with ethyl acetate–sodium sulfate and cleanup on silica solid-phase extraction cartridges using dichloromethane–2-propanol (9 + 1) as eluant. The eluate is dried under nitrogen and redissolved in methanol. Benzoylurea insecticides are determined by reversed-phase LC with gradient elution at 42°C and UV diode array detection. Recoveries from samples fortified with the 5 insecticides at 0.02–0.5 mg/kg ranged from 83 to 102% for apples and from 75 to 99% for pears. Relative standard deviations were 0–12%. Limits of detection were 0.01 mg/kg for apples and 0.02 mg/kg for pears.

scholarly journals Optimization of QuEChERS Method for Simultaneous Determination of Neonicotinoid Residues in Pollinator Forage

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2732 ◽  
Author(s):  
Maura J. Hall ◽  
Viet Dang ◽  
Steven P. Bradbury ◽  
Joel R. Coats
Keyword(s):  
Crop Production ◽  
Large Scale ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Soybean Seed ◽  
Leaf Tissue ◽  
Gradient Elution ◽  
Reversed Phase ◽  
History Of

Consistent with the large-scale use of pesticide seed treatments in U.S. field crop production, there has been an increased use of neonicotinoid-treated corn and soybean seed over the past decade. Neonicotinoids can move downwind to adjacent off-field pollinator habitats in dust from planting and/or move downslope to habitats in surface water. The extent of potential neonicotinoid exposure to pollinators from neonicotinoid movement into these adjacent pollinator habitats is unclear. Pollen and leaf tissue extractions were completed using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction procedure. Samples were subjected to a clean-up step using dispersive solid-phase extraction (dSPE) techniques prior to analysis. The compounds in the extracts were separated on a reversed-phase column with gradient elution and confirmed with tandem mass spectrometry. The extraction method showed acceptable recoveries of analytes ranging from 78.4 to 93.6% and 89.4 to 101% for leaf tissue and pollen, respectively. The method’s detection limits ranged from 0.04 to 0.3 ng/g in milkweed leaf tissue and 0.04 to 1.0 ng/g in pollen. The method is currently being employed in ongoing studies surveying pollen from a diversity of forbs and milkweed leaves obtained from habitat patches established within fields with a history of using neonicotinoid-treated seeds.

Simultaneous determination of deoxynivalenol, and 15- and 3-acetyldeoxynivalenol in cereals by HPLC-UV detection

2013 ◽  
Vol 6 (2) ◽  
pp. 117-125 ◽  
Author(s):  
D. Yang ◽  
Z.M. Geng ◽  
J.B. Yao ◽  
X. Zhang ◽  
P.P. Zhang ◽  
...  
Keyword(s):  
Solid Phase ◽  
Animal Health ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Uv Detection ◽  
Cereal Grains ◽  
Cereal Crop ◽  
Head Blight ◽  
Crop Disease

Fusarium head blight is an important cereal crop disease, which not only causes yield losses but also mycotoxin contamination in wheat and other cereal grains. Developing an accurate, rapid and efficient assay is critical to minimise the risk of Fusarium mycotoxins for human and animal health. In this study, HPLC with UV detection was used to separate and quantify deoxynivalenol, 15-acetyldeoxynivalenol and 3-acetyldeoxynivalenol in cereals. Samples were extracted with water, and the extracting solution was precipitated by adding an equal volume of ethanol followed by solid-phase extraction. The analytes were separated on a reversed-phase C18 column by a mobile phase composed of acetonitrile and 1 mM H3PO4 with gradient elution. 15- and 3-acetyldeoxynivalenol showed effective baseline separation. All analytes were well-resolved from matrix co-extractives and detected at 224 nm. The results showed good linearity of calibration curves (R2 ranged from 0.997 to 0.999) and excellent precision for inter- and intra-day determinations. Average recovery rates for the tested matrices ranged from 71 to 92%. The limits of detection and quantification ranged from 16 to 25 ng/g and 48 to 60 ng/g, respectively. The results indicate that the feasibility and practicality of the presented LC-UV method are excellent and that the method is suitable for routine analysis of DON and its acetyl derivatives in cereal grains.

scholarly journals Multiresidue Determination of Eleven Quinolones in Milk by Liquid Chromatography with Fluorescence Detection

2005 ◽  
Vol 88 (6) ◽  
pp. 1688-1694 ◽  
Author(s):  
Guixiang Yang ◽  
Baoyin Lin ◽  
Zhenling Zeng ◽  
Zhangliu Chen ◽  
Xianhui Huang
Keyword(s):  
Fluorescence Detection ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Phase Gradient ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Multiresidue Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method with fluorescence detection was developed for simultaneous determination of norfloxacin, ofloxacin, ciprofloxacin, pefloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, and flumequine in milk. The samples were extracted with 10% trichloroacetic acid/acetonitrile (9 + 1, v/v) and cleaned by Strata-X reversed-phase solid-phase extraction cartridges. The 11 quinolones were separated on a reversed-phase C18 column (Hypersil BDS-C18) with mobile phase gradient elution and detected with fluorescence by means of a wavelength program. The recoveries for milk fortified with the 11 quinolones at 3 levels were 69–88%, with acceptable relative standard deviations of &lt;9% (intraday) and &lt;14% (interday). The limits of detection were 23 μg/L for enrofloxacin, and 1–9 μg/L for the other 10 quinolones.

LC–MS-MS Method for the Determination of Antidepressants and Benzodiazepines in Meconium

2020 ◽  
Vol 44 (6) ◽  
pp. 580-588
Author(s):  
A López-Rabuñal ◽  
E Lendoiro ◽  
M Concheiro ◽  
M López-Rivadulla ◽  
A Cruz ◽  
...  
Keyword(s):  
Extraction Efficiency ◽  
Solid Phase ◽  
Gradient Methods ◽  
Reversed Phase ◽  
Process Efficiency ◽  
Limit Of Quantification ◽  
Mode 2 ◽  
Positive Mode ◽  
Compound Method

Abstract An LC–MS-MS method for the determination of 14 benzodiazepines (BZDs) (alprazolam, α-hydroxyalprazolam, clonazepam, bromazepam, diazepam, nordiazepam, lorazepam, lormetazepam, oxazepam, flunitrazepam, 7-aminoflunitrazepam, triazolam, midazolam and zolpidem) and 15 antidepressants (ADs) (amitriptyline, nortriptyline, imipramine, desipramine, clomipramine, norclomipramine, fluoxetine, norfluoxetine, sertraline, norsertraline, paroxetine, venlafaxine, desmethylvenlafaxine, citalopram and desmethylcitalopram) in meconium was developed and validated. Meconium samples (0.25 ± 0.02 g) were homogenized in methanol and subjected to mixed-mode cation exchange solid-phase extraction. Chromatographic separation was performed in reversed phase, with a gradient of 0.1% formic acid in 2 mM ammonium formate and acetonitrile. Two different chromatographic gradient methods were employed, one for the separation of ADs and another for BZDs. Analytes were monitored by tandem mass spectrometry employing electrospray positive mode in MRM mode (2 transitions per compound). Method validation included: linearity [n = 5, limit of quantification (LOQ) to 400 ng/g], limits of detection (n = 6, 1–20 ng/g), LOQ (n = 9, 5–20 ng/g), selectivity (no endogenous or exogenous interferences), accuracy (n = 15, 90.6–111.5%), imprecision (n = 15, 0–14.6%), matrix effect (n = 10, −73 to 194.9%), extraction efficiency (n = 6, 35.9–91.2%), process efficiency (n = 6, 20.1–188.2%), stability 72 h in the autosampler (n = 3, −8.5 to 9%) and freeze/thaw stability (n = 3, −1.2 to −47%). The method was applied to four meconium specimens, which were analyzed with and without hydrolysis (enzymatic and alkaline). The authentic meconium samples tested positive for alprazolam, α-hydroxyalprazolam, clonazepam, diazepam, nordiazepam, fluoxetine, norfluoxetine, clomipramine and norclomipramine. Therefore, the present LC–MS-MS method allows a high throughput determination of the most common BZDs and ADs in meconium, which could be useful in clinical and forensic settings.

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