Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Tevis DS[original query] |
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Harmonization of acronyms for volatile organic compound metabolites using a standardized naming system
Tevis DS , Flores SR , Kenwood BM , Bhandari D , Jacob P3rd , Liu J , Lorkiewicz PK , Conklin DJ , Hecht SS , Goniewicz ML , Blount BC , De Jesús VR . Int J Hyg Environ Health 2021 235 113749 Increased interest in volatile organic compound (VOC) exposure has led to an increased need for consistent, systematic, and informative naming of VOC metabolites. As analytical methods have expanded to include many metabolites in a single assay, the number of acronyms in use for a single metabolite has expanded in an unplanned and inconsistent manner due to a lack of guidance or group consensus. Even though the measurement of VOC metabolites is a well-established means to investigate exposure to VOCs, a formal attempt to harmonize acronyms amongst investigators has not been published. The aim of this work is to establish a system of acronym naming that provides consistency in current acronym usage and a foundation for creating acronyms for future VOC metabolites. |
Development of a pregnancy-specific referencematerial for thyroid biomarkers, vitaminD, and nutritional trace elements in serum
Boggs ASP , Kilpatrick LE , Burdette CQ , Tevis DS , Fultz ZA , Nelson MA , Jarrett JM , Kemp JV , Singh RJ , Grebe SKG , Wise SA , Kassim BL , Long SE . Clin Chem Lab Med 2020 59 (4) 671-679 Objectives Matrix differences among serum samples from non-pregnant and pregnant patients could bias measurements. Standard Reference Material 1949, Frozen Human Prenatal Serum, was developed to provide a quality assurance material for the measurement of hormones and nutritional elements throughout pregnancy. Methods Serum from non-pregnant women and women in each trimester were bottled into four levels based on pregnancy status and trimester. Liquid chromatography tandem mass spectrometry (LC-MS/MS) methods were developed and applied to the measurement of thyroid hormones, vitamin D metabolites, and vitamin D-binding protein (VDBP). Copper, selenium, and zinc measurements were conducted by inductively coupled plasma dynamic reaction cell MS. Thyroid stimulating hormone (TSH), thyroglobulin (Tg), and thyroglobulin antibody concentrations were analyzed using immunoassays and LC-MS/MS (Tg only). Results Certified values for thyroxine and triiodothyronine, reference values for vitamin D metabolites, VDBP, selenium, copper, and zinc, and information values for reverse triiodothyronine, TSH, Tg, and Tg antibodies were assigned. Significant differences in serum concentrations were evident for all analytes across the four levels (p≤0.003). TSH measurements were significantly different (p<0.0001) among research-only immunoassays. Tg concentrations were elevated in research-only immunoassays vs. Federal Drug Administration-approved automated immunoassay and LC-MS/MS. Presence of Tg antibodies increased differences between automated immunoassay and LC-MS/MS. Conclusions The analyte concentrations' changes consistent with the literature and the demonstration of matrix interferences in immunoassay Tg measurements indicate the functionality of this material by providing a relevant matrix-matched reference material for the different stages of pregnancy. |
Large differences in urinary benzene metabolite s-phenylmercapturic acid quantitation: A comparison of five LC-MS-MS methods
Tevis DS , Willmore A , Bhandari D , Bowman B , Biren C , Kenwood BM , Jacob P , Liu J , Bello K , Hecht SS , Carmella SG , Chen M , Gaudreau E , Bienvenu JF , Blount BC , De Jesús VR . J Anal Toxicol 2020 45 (7) 657-665 Benzene is a known genotoxic carcinogen linked to many hematological abnormalities. S-phenylmercapturic acid (PHMA, N-Acetyl-S-(phenyl)-L-cysteine, CAS# 4775-80-8) is a urinary metabolite of benzene and is used as a biomarker to assess benzene exposure. Pre-S-phenylmercapturic acid (pre-PHMA) is a PHMA precursor that dehydrates to PHMA at acidic pH. Published analytical methods that measure urinary PHMA adjust urine samples to a wide range of pH values using several types of acid, potentially leading to highly variable results depending on the concentration of pre-PHMA in a sample. Information is lacking on the variation in sample preparation among laboratories regularly measuring PHMA and the effect of those differences on PHMA quantitation in human urine samples. To investigate the differences in PHMA quantitation, we conducted an inter-laboratory comparison that included the analysis of 50 anonymous human urine samples (25 self-identified smokers, 25 self-identified non-smokers), quality control samples, and commercially available reference samples in five laboratories using different analytical methods to determine which sample preparation methods are currently in use and compare PHMA results. Observed urinary PHMA concentrations were proportionally higher at lower pH and results for anonymous urine samples varied widely among the methods. The method with the neutral preparation pH yielded results about 60% lower than the method using the most acidic conditions. Samples spiked with PHMA showed little variation, suggesting that the variability in results in human urine samples across methods is driven by the acid-mediated conversion of pre-PHMA to PHMA. |
Assessing the stability of Cd, Mn, Pb, Se, and total Hg in whole human blood by ICP-DRC-MS as a function of temperature and time
Tevis DS , Jarrett JM , Jones DR , Cheng PY , Franklin M , Mullinex N , Caldwell KL , Jones RL . Clin Chim Acta 2018 485 1-6 BACKGROUND: Comprehensive information on the effect of time and temperature storage on the measurement of elements in human, whole blood (WB) by inductively coupled plasma-dynamic reaction cell-mass spectrometry (ICP-DRC-MS) is lacking, particularly for Mn and Se. METHODS: Human WB was spiked at 3 concentration levels, dispensed, and then stored at 5 different temperatures: -70 degrees C, -20 degrees C, 4 degrees C, 23 degrees C, and 37 degrees C. At 3 and 5weeks, and at 2, 4, 6, 8, 10, 12, 36months, samples were analyzed for Pb, Cd, Mn, Se and total Hg, using ICP-DRC-MS. We used a multiple linear regression model including time and temperature as covariates to fit the data with the measurement value as the outcome. We used an equivalence test using ratios to determine if results from the test storage conditions, warmer temperature and longer time, were comparable to the reference storage condition of 3weeks storage time at -70 degrees C. RESULTS: Model estimates for all elements in human WB samples stored in polypropylene cryovials at -70 degrees C were equivalent to estimates from samples stored at 37 degrees C for up to 2months, 23 degrees C up to 10months, and -20 degrees C and 4 degrees C for up to 36months. Model estimates for samples stored for 3weeks at -70 degrees C were equivalent to estimates from samples stored for 2months at -20 degrees C, 4 degrees C, 23 degrees C and 37 degrees C; 10months at -20 degrees C, 4 degrees C, and 23 degrees C; and 36months at -20 degrees C and 4 degrees C. This equivalence was true for all elements and pools except for the low concentration blood pool for Cd. CONCLUSIONS: Storage temperatures of -20 degrees C and 4 degrees C are equivalent to -70 degrees C for stability of Cd, Mn, Pb, Se, and Hg in human whole blood for at least 36months when blood is stored in sealed polypropylene vials. Increasing the sample storage temperature from -70 degrees C to -20 degrees C or 4 degrees C can lead to large energy savings. The best analytical results are obtained when storage time at higher temperature conditions (e.g. 23 degrees C and 37 degrees C) is minimized because recovery of Se and Hg is reduced. Blood samples stored in polypropylene vials also lose volume over time and develop clots at higher temperature conditions (e.g., 23 degrees C and 37 degrees C), making them unacceptable for elemental testing after 10months and 2months, respectively. |
Analysis of whole human blood for Pb, Cd, Hg, Se, and Mn by ICP-DRC-MS for biomonitoring and acute exposures
Jones DR , Jarrett JM , Tevis DS , Franklin M , Mullinix NJ , Wallon KL , Derrick Quarles C Jr , Caldwell KL , Jones RL . Talanta 2017 162 114-122 We improved our inductively coupled plasma mass spectrometry (ICP-MS) whole blood method [1] for determination of lead (Pb), cadmium (Cd), and mercury (Hg) by including manganese (Mn) and selenium (Se), and expanding the calibration range of all analytes. The method is validated on a PerkinElmer (PE) ELAN® DRC II ICP-MS (ICP-DRC-MS) and uses the Dynamic Reaction Cell (DRC) technology to attenuate interfering background ion signals via ion-molecule reactions. Methane gas (CH4) eliminates background signal from 40Ar2 + to permit determination of 80Se+, and oxygen gas (O2) eliminates several polyatomic interferences (e.g. 40Ar15N+, 54Fe1H+) on 55Mn+. Hg sensitivity in DRC mode is a factor of two higher than vented mode when measured under the same DRC conditions as Mn due to collisional focusing of the ion beam. To compensate for the expanded method's longer analysis time (due to DRC mode pause delays), we implemented an SC4-FAST autosampler (ESI Scientific, Omaha, NE), which vacuum loads the sample onto a loop, to keep the sample-to-sample measurement time to less than 5 min, allowing for preparation and analysis of 60 samples in an 8-h work shift. The longer analysis time also resulted in faster breakdown of the hydrocarbon oil in the interface roughing pump. The replacement of the standard roughing pump with a pump using a fluorinated lubricant, Fomblin®, extended the time between pump maintenance. We optimized the diluent and rinse solution components to reduce carryover from high concentration samples and prevent the formation of precipitates. We performed a robust calculation to determine the following limits of detection (LOD) in whole blood: 0.07 µg dL−1 for Pb, 0.10 µg L−1 for Cd, 0.28 μg L−1 for Hg, 0.99 µg L−1 for Mn, and 24.5 µg L−1 for Se. © 2016 |
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