Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Garton JW[original query] |
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Simultaneous measurement of 3-chlorotyrosine and 3,5-dichlorotyrosine in whole blood, serum and plasma by isotope dilution HPLC-MS-MS
Crow BS , Quinones-Gonzalez J , Pantazides BG , Perez JW , Winkeljohn WR , Garton JW , Thomas JD , Blake TA , Johnson RC . J Anal Toxicol 2016 40 (4) 264-71 Chlorine is a public health concern and potential threat due to its high reactivity, ease and scale of production, widespread industrial use, bulk transportation, massive stockpiles and history as a chemical weapon. This work describes a new, sensitive and rapid stable isotope dilution method for the retrospective detection and quantitation of two chlorine adducts. The biomarkers 3-chlorotyrosine (Cl-Tyr) and 3,5-dichlorotyrosine (Cl2-Tyr) were isolated from the pronase digest of chlorine exposed whole blood, serum or plasma by solid-phase extraction (SPE), separated by reversed-phase HPLC and detected by tandem mass spectrometry (MS-MS). The calibration range is 2.50-1,000 ng/mL (R2 ≥ 0.998) with a lowest reportable limit (LRL) of 2.50 ng/mL for both analytes, an accuracy of ≥93% and an LOD of 0.443 ng/mL for Cl-Tyr and 0.396 ng/mL for Cl2-Tyr. Inter- and intra-day precision of quality control samples had coefficients of variation of ≤10% and ≤7.0%, respectively. Blood and serum samples from 200 healthy individuals and 175 individuals with chronic inflammatory disease were analyzed using this method to assess background levels of chlorinated tyrosine adducts. Results from patients with no known inflammatory disease history (healthy) showed baseline levels of <LRL-4.26 ng/mL Cl-Tyr and <LRL Cl2-Tyr. Patients with inflammatory disease had baseline levels of <LRL-15.4 ng/mL Cl-Tyr and <LRL-5.22 ng/mL Cl2-Tyr. Blood exposed to 2.02 ppm chlorine gas for 15 min produced 941 ng/mL Cl-Tyr and 223 ng/mL Cl2-Tyr. This high-throughput method has been developed and analytically validated for the diagnosis of human exposure to chlorine. |
Simplified method for quantifying sulfur mustard adducts to blood proteins by ultrahigh pressure liquid chromatography-isotope dilution tandem mass spectrometry
Pantazides BG , Crow BS , Garton JW , Quinones-Gonzalez JA , Blake TA , Thomas JD , Johnson RC . Chem Res Toxicol 2015 28 (2) 256-61 Sulfur mustard binds to reactive cysteine residues, forming a stable sulfur-hydroxyethylthioethyl [S-HETE] adduct that can be used as a long-term biomarker of sulfur mustard exposure in humans. The digestion of sulfur mustard-exposed blood samples with proteinase K following total protein precipitation with acetone produces the tripeptide biomarker [S-HETE]-Cys-Pro-Phe. The adducted tripeptide is purified by solid phase extraction, separated by ultrahigh pressure liquid chromatography, and detected by isotope dilution tandem mass spectrometry. This approach was thoroughly validated and characterized in our laboratory. The average interday relative standard deviation was ≤9.49%, and the range of accuracy was between 96.1 and 109% over a concentration range of 3.00 to 250. ng/mL with a calculated limit of detection of 1.74 ng/mL. A full 96-well plate can be processed and analyzed in 8 h, which is 5 times faster than our previous 96-well plate method and only requires 50 muL of serum, plasma, or whole blood. Extensive ruggedness and stability studies and matrix comparisons were conducted to create a robust, easily transferrable method. As a result, a simple and high-throughput method has been developed and validated for the quantitation of sulfur mustard blood protein adducts in low volume blood specimens which should be readily adaptable for quantifying human exposures to other alkylating agents. |
Simultaneous measurement of tabun, sarin, soman, cyclosarin, VR, VX, and VM adducts to tyrosine in blood products by isotope dilution UHPLC-MS/MS
Crow BS , Pantazides BG , Quinones-Gonzalez J , Garton JW , Carter MD , Perez JW , Watson CM , Tomcik DJ , Crenshaw MD , Brewer BN , Riches JR , Stubbs SJ , Read RW , Evans RA , Thomas JD , Blake TA , Johnson RC . Anal Chem 2014 86 (20) 10397-405 This work describes a new specific, sensitive, and rapid stable isotope dilution method for the simultaneous detection of the organophosphorus nerve agents (OPNAs) tabun (GA), sarin (GB), soman (GD), cyclosarin (GF), VR, VX, and VM adducts to tyrosine (Tyr). Serum, plasma, and lysed whole blood samples (50 muL) were prepared by protein precipitation followed by digestion with Pronase. Specific Tyr adducts were isolated from the digest by a single solid phase extraction (SPE) step, and the analytes were separated by reversed-phase ultra high performance liquid chromatography (UHPLC) gradient elution in less than 2 min. Detection was performed on a triple quadrupole tandem mass spectrometer using time-triggered selected reaction monitoring (SRM) in positive electrospray ionization (ESI) mode. The calibration range was characterized from 0.100-50.0 ng/mL for GB- and VR-Tyr and 0.250-50.0 ng/mL for GA-, GD-, GF-, and VX/VM-Tyr (R2 ≥ 0.995). Inter- and intra-assay precision had coefficients of variation of ≤17 and ≤10%, respectively, and the measured concentration accuracies of spiked samples were within 15% of the targeted value for multiple spiking levels. The limit of detection was calculated to be 0.097, 0.027, 0.018, 0.074, 0.023, and 0.083 ng/mL for GA-, GB-, GD-, GF-, VR-, and VX/VM-Tyr, respectively. A convenience set of 96 serum samples with no known nerve agent exposure was screened and revealed no baseline values or potential interferences. This method provides a simple and highly specific diagnostic tool that may extend the time postevent that a confirmation of nerve agent exposure can be made with confidence. |
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