Simultaneous quantification of the organophosphorus pesticides dimethoate and omethoate in porcine plasma and urine by LC–ESI-MS/MS and flow-injection-ESI-MS/MS

John, Harald; Eddleston, Michael; Clutton, R Eddie; Worek, Franz; Thiermann, Horst

doi:10.1016/j.jchromb.2010.01.003

Cited by 44 publications

(28 citation statements)

References 45 publications

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“…Similar methods are now used in many nationwide neonatal screening programs [23,24]. In the fields of pesticide determination [25,26,27], therapeutic drug monitoring [28] and analysis of adulterated dietary supplements [29], FIA-MS/MS has recently been presented as an adequate alternative to LC-MS/MS. For FIA-MS/MS the mass spectrometer is directly coupled to a pump delivering a continuous flow of eluent solvents, whereas the LC column compartment is bypassed.…”

Section: Introductionmentioning

confidence: 99%

Determination of Creatinine in Human Urine with Flow Injection Tandem Mass Spectrometry

Niesser

Koletzko²,

Peißner³

2012

Ann Nutr Metab

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Background/Aims: Excretion of urinary compounds in spot urine is often estimated relative to creatinine. For the growing number of liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays of urine-excreted molecules, a fast and accurate method for determination of creatinine is needed. Methods: A high-throughput flow injection tandem mass spectrometry method for exact quantitation of creatinine in urine has been developed and validated. Sample preparation used only two-step dilution for protein precipitation and matrix dilution. Flow injection analysis without chromatographic separation allowed for total run times of 1 min per sample. Creatinine concentrations were quantitated using stable isotope dilution tandem mass spectrometry. Selectivity and coelution-free quantitation were assured by qualifier ion monitoring. Results: Method validation revealed excellent injection repeatability of 1.0% coefficient of variation (CV), intraday precision of 1.2% CV and interday precision of 2.4% CV. Accuracy determined from standard addition experiments was 106.1 ± 3.8%. The linear calibration range was adapted to physiological creatinine concentrations. Comparison of quantitation results with a routinely used method (Jaffé colorimetric assay) proved high agreement (R² = 0.9102). Conclusions: The new method is a valuable addition to the toolbox of LC-MS/MS laboratories where excretion of urinary compounds is studied. The ‘dilute and shoot’ approach to isotope dilution tandem mass spectrometry makes the new method highly accurate as well as cost- and time-efficient.

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Section: Introductionmentioning

confidence: 99%

Determination of Creatinine in Human Urine with Flow Injection Tandem Mass Spectrometry

Niesser

Koletzko²,

Peißner³

2012

Ann Nutr Metab

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“…[31] Pesticides were chromatographed under standard conditions except the run time was prolonged to 40 min and the DAD was set to monitor absorbance between 200 and 356 nm. [31] Pesticides were chromatographed under standard conditions except the run time was prolonged to 40 min and the DAD was set to monitor absorbance between 200 and 356 nm.…”

Section: Selectivitymentioning

confidence: 99%

Quantification of pralidoxime (2‐PAM) in urine by ion pair chromatography‐diode array detection: application to in vivo samples from minipig

John

Eddleston

Clutton

et al. 2011

Drug Testing and Analysis

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Pralidoxime (2-PAM) is a monopyridinium oxime used as an antidote for the treatment of poisoning with organophosphorus (OP) compounds, for example, pesticides and nerve agents, reactivating OP-inhibited acetylcholinesterase. However, appropriate dosing and efficacy remains a matter of discussion requiring experimental data. Therefore, we developed and validated an ion pair chromatography-diode array detection (IPC-DAD) method suitable for quantitative analysis of 2-PAM in human and porcine urine. Before injection of 20 µl, urine was acidified with trichloroacetic acid, mixed with internal standard (pyridine-4-aldoxime, 4-PAO), and diluted with IPC solvent yielding a total dilution of 1:49.5 and a 100% recovery. Isocratic separation was carried out at 25 °C on a LiChrospher 60 RP-select B column (125 x 4.0 mm I.D.) using phosphate buffer (7.5 mM Na(2) HPO(4) , 7.5 mM KH(2) PO(4) , pH 2.6) mixed with octanesulfonate (2.5 mM) as ion pair reagent and acetonitrile (6% v/v) as organic modifier (1 ml/min). 2-PAM was detected at 293 nm and 4-PAO at 275 nm. The method is rugged, selective, and characterized by good intra-day and inter-day precision (RSD, 1.3-6.0%) and accuracy (88-100%) with a limit of detection at 4.9 µg/ml, a limit of quantification at 9.8 µg/ml, and a broad calibration range from 4.9-2500 µg/ml. The procedure was applied to urine samples obtained from dimethoate poisoned minipigs receiving 2-PAM therapy (intravenous bolus injection and infusion). Results indicate that 60-80% of infused 2-PAM is rapidly (within 1-2 h) excreted in the urine.

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“…Recently, we introduced a novel, precise, and accurate enzymatic enantioselective HPLC-MS/MS procedure for sensitive quantification of both hyo variants in plasma, which allows for the stereoselective analysis of concentration-time profiles in in vivo studies. [6,[23][24][25] Therefore this study has applied the recently published enantioselective HPLC-MS/MS procedure to monitor hyoscamine concentrations in swine plasma after i.v. [6,[23][24][25] Therefore this study has applied the recently published enantioselective HPLC-MS/MS procedure to monitor hyoscamine concentrations in swine plasma after i.v.…”

Section: Introductionmentioning

confidence: 99%

Application of an enantioselective LC‐ESI MS/MS procedure to determine R‐ and S‐hyoscyamine following intravenous atropine administration in swine

John¹,

Mikler

Worek³

et al. 2011

Drug Testing and Analysis

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S-hyoscyamine (S-hyo) is a natural plant tropane alkaloid acting as a muscarinic receptor (MR) antagonist. Its racemic mixture (atropine) is clinically used in pre-anaesthesia, ophthalmology and for the antidotal treatment of organophosphorus (OP) poisoning with nerve agents or pesticides even though R-hyo exhibits no effects on MR. Further investigative research is required to optimize treatment of OP poisoning. Swine are often the animal model utilized due to similarities in physiology and antidote response to humans. However, no studies have been reported that elucidated differences in the kinetics of R- and S-hyo. Therefore, the concentration-time profiles of total hyo as well as both enantiomers were analyzed in plasma after intravenous administration of atropine sulfate (Atr(2) SO(4) , 100 µg/kg) to anaesthetized swine. For quantification plasma samples were incubated separately with human serum (procedure A) and rabbit serum (procedure B). The rabbit serum used contained atropinesterase, which is suitable for stereoselective hydrolysis of S-hyo, while human serum does not hydrolyze either enantiomer. After incubation samples were precipitated and the supernatant was analyzed by RP-HPLC-ESI MS/MS. Procedure A allowed determination of total hyo and procedure B remaining R-hyo concentrations. S-hyo was calculated as the difference of the two procedures. Concentration data were regressed by a two-phase decay according to a two-compartment open model revealing similar kinetics for both enantiomers thus indicating distribution, metabolism and elimination without obvious stereoselective preference in tested swine.

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Simultaneous quantification of the organophosphorus pesticides dimethoate and omethoate in porcine plasma and urine by LC–ESI-MS/MS and flow-injection-ESI-MS/MS

Cited by 44 publications

References 45 publications

Determination of Creatinine in Human Urine with Flow Injection Tandem Mass Spectrometry

Determination of Creatinine in Human Urine with Flow Injection Tandem Mass Spectrometry

Quantification of pralidoxime (2‐PAM) in urine by ion pair chromatography‐diode array detection: application to in vivo samples from minipig

Application of an enantioselective LC‐ESI MS/MS procedure to determine R‐ and S‐hyoscyamine following intravenous atropine administration in swine

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