Median Regression for Longitudinal Left-Censored Biomarker Data Subject to Detection Limit

A sensitive colorimetric determination of fluoride in drinking water has been developed using a polymeric zirconium complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline as fluoride reagents. The method allowed a reliable determination of fluoride in range of (0.0-1.5) mg L-1. The molar absorptivity of the complex formation is 7695 ± 27 L mol-1 cm-1 at 460 nm. The sensitivity, detection limit, quantitation limit, and percentage recovery for 1.0 mg L-1 fluoride for the proposed method were found to be 0.353 ± 0.013 μg mL-1, 0.1 mg L-1, 0.3 mg L-1, and 101.7 ± 4.1, respectively.

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Insecticide Residues on 1972 U.S. Auction-Market Tobacco

Beiträge zur Tabakforschung International/Contributions to Tobacco Research ◽

10.2478/cttr-2013-0353 ◽

1975 ◽

Vol 8 (1) ◽

Author(s):

J. J. Domanski ◽

P. L. Haire ◽

T.J. Sheets

Keyword(s):

Detection Limit ◽

Auction Market ◽

Insecticide Residues ◽

Low Detection Limit ◽

Average Residue ◽

The Individual ◽

In Fire

AbstractAverage residue Ievels of DDT + TDE in flue-cured tobacco decreased from 6.1 ppm in 1970 to 0.85 ppm in 1972. DDT + TDE residues in Burley also dropped sharply from previous levels. In 1972 one sample from Kentucky contained 8.17 ppm; all other Burley samples were less than 0.25 ppm. DDT + TDE residues also declined in fire-cured and air-cured types; of these samples Tennessee dark air-cured tobacco contained the highest average residue (3.5 ppm of DDT + TDE). In 1972 over 90 % of the flue-cured samples were positive for toxaphene. Since each of our samples was a composite of tobacco from 10 farmers, we cannot conclude from this result that 90 % of the individual piles contained toxaphene. Significant amounts of toxaphene were found in other types also; for example, 50 % of the 1972 Burley samples had toxaphene concentrations greater than 0.5 ppm. Average endosulfan levels decreased between 1970 and 1972 in flue-cured and Burley tobaccos. However, in all of the dark air and dark fire-cured samples from Tennessee endosulfan residues exceeded 5 ppm. Average endrin residues were at or near the low detection limit in alI samples except fire-cured and dark air-cured tobacco from Tennessee; these averaged 0.26 and 0.17 ppm, respectively.

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Analytical Performance of the NOVEOS Allergen-Specific IgE Assay: Precision and Detection Limit Studies.

10.26226/morressier.5acc8acfd462b8028d89a87f ◽

2018 ◽

Author(s):

Douglas Evans

Keyword(s):

Detection Limit ◽

Specific Ige ◽

Analytical Performance ◽

Assay Precision

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Oil to Source Rock Correlation Using Biomarker Data Through Pattern Matching and Fingerprinting Analysis in “Kitkat” Field, Jabung Block, South Sumatra Basin

Proc. Indon. Petrol. Assoc., Digital Technical Conference, 2020 ◽

10.29118/ipa20-sg-251 ◽

2020 ◽

Author(s):

S., R. Muthasyabiha

Keyword(s):

Pattern Matching ◽

Source Rock ◽

Vitrinite Reflectance ◽

Hydrocarbon Exploration ◽

Source Rocks ◽

Maturity Level ◽

Fingerprinting Analysis ◽

Kerogen Type ◽

Oil Characteristics ◽

Biomarker Data

Geochemical analysis is necessary to enable the optimization of hydrocarbon exploration. In this research, it is used to determine the oil characteristics and the type of source rock candidates that produces hydrocarbon in the “KITKAT” Field and also to understand the quality, quantity and maturity of proven source rocks. The evaluation of source rock was obtained from Rock-Eval Pyrolysis (REP) to determine the hydrocarbon type and analysis of the value of Total Organic Carbon (TOC) was performed to know the quantity of its organic content. Analysis of Tmax value and Vitrinite Reflectance (Ro) was also performed to know the maturity level of the source rock samples. Then the oil characteristics such as the depositional environment of source rock candidate and where the oil sample develops were obtained from pattern matching and fingerprinting analysis of Biomarker data GC/GCMS. Moreover, these data are used to know the correlation of oil to source rock. The result of source rock evaluation shows that the Talangakar Formation (TAF) has all these parameters as a source rock. Organic material from Upper Talangakar Formation (UTAF) comes from kerogen type II/III that is capable of producing oil and gas (Espitalie, 1985) and Lower Talangakar Formation (LTAF) comes from kerogen type III that is capable of producing gas. All intervals of TAF have a quantity value from very good–excellent considerable from the amount of TOC > 1% (Peters and Cassa, 1994). Source rock maturity level (Ro > 0.6) in UTAF is mature–late mature and LTAF is late mature–over mature (Peters and Cassa, 1994). Source rock from UTAF has deposited in the transition environment, and source rock from LTAF has deposited in the terrestrial environment. The correlation of oil to source rock shows that oil sample is positively correlated with the UTAF.

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