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A novel CuS grafted PEDOT:PSS conducting paper-based electrochemical immunosensor has been successfully fabricated for the detection of EpCAM antigen. Electrical conductivity is further improved by doping the CuS@PEDOT:PSS/WP electrode with different organic solvents such as N,N-dimethyl formamide (DMF), N,N-dimethyl acetamide (DMA), ethylene glycol (EG) and dimetyl sulfoxide (DMSO). It is observed that DMSO doped conducting paper shows the highest conductivity (6.1 × 10−2 S/cm) among all these solvents. This low cost, biodegradable electrochemical paper-based immunosensor (BSA/anti-EpCAM/EP) possesses a broad linear range from 0.01 pg/mL to 1000 ng/mL for EpCAM antigen detection. The immunosensor is found to have high sensitivity of 104.31 μA pg−1 mL. This conducting paper based immunosensor is further used to detect EpCAM antigen in human serum samples, thereby confirming a cost effective clinical tool over other costly conventional techniques. • An electrochemical paper-based immunosensor has been designed using CuS and PEDOT:PSS. • This low cost and flexible platform may be a promising candidate over other costly conventional electrodes. • It exhibits high sensitivity of 104.31 μA pg−1 mL in broad range of 0.01 pg/mL to 1000 ng/mL, for EpCAM detection. • The clinical applicability and validity has been checked with human serum sample. [ABSTRACT FROM AUTHOR]

One of the major components of the organic solvent extractable fraction of Cretaceous ambers is 1,6-dimethyl-5-isopentyltetralin, a compound that has been incorrectly or not identified in previous reports on the molecular composition of Cretaceous ambers. Here, the purification and structural identification of 1,6-dimethyl-5-isopentyltetralin is reported from amber samples of the Cretaceous Peñacerrada II deposit at Peñacerrada, Álava (Basque-Cantabrian Basin, Spain). The structural identification of 1,6-dimethyl-5-isopentyltetralin allowed the complete identification of related compounds, comprising the family of 1,6-dimethyl-5-alkyltetralins. This suggests that those compounds, with concentrations up to 27% of the total organic extract of amber from Peñacerrada, are characteristic for labdane-type biomarkers in Cretaceous fossil resins and their distributions indicate different compositional families, related to their botanical and topographic origin. Also, the name amberene is proposed for the main molecule of this group. The relative proportion of the amberene-type compounds suggests three compositional families for the Cretaceous Spanish ambers. [ABSTRACT FROM AUTHOR]

N -alkyl-2-pyrrolidones are important organic solvents for varnishes in industry. This study investigates exposure to N -ethyl-2-pyrrolidone (NEP) in varnishing of hard plastic components in an automobile plant. Two specific biomarkers of exposure, 5-hydroxy- N -ethyl-2-pyrrolidone (5-HNEP) and 2-hydroxy- N -ethylsuccinimide (2-HESI), were analyzed in urine samples of 14 workers. For this purpose, pre-shift, post-shift and next day pre-shift urine samples were collected midweek. Twelve workers performed regular work tasks (loading, wiping and packing), whereas two workers performed special work tasks including cleaning the sprayer system with organic solvents containing N -alkyl-2-pyrrolidones. Spot urine samples of nine non-exposed persons of the same plant served as controls. Median post-shift urinary levels of workers with regular work tasks (5-HNEP: 0.15 mg/L; 2-HESI: 0.19 mg/L) were ∼5-fold higher compared to the controls (0.03 mg/L each). Continuously increasing metabolite levels, from pre-shift via post-shift to pre-shift samples of the following day, were observed in particular for the two workers with the special working tasks. Maximum levels were 31.01 mg/L (5-HNEP) and 8.45 mg/L (2-HESI). No clear trend was evident for workers with regular working tasks. In summary, we were able to show that workers can be exposed to NEP during varnishing tasks in the automobile industry. [ABSTRACT FROM AUTHOR]

The first step in many life detection protocols on Mars involves attempts to extract or isolate organic matter from its mineral matrix. A number of extraction options are available and include heat and solvent assisted methods. Recent operations on Mars indicate that heating samples can cause the loss or obfuscation of organic signals from target materials, raising the importance of solvent-based systems for future missions. Several solvent types are available (e.g. organic solvents, surfactant based solvents and subcritical water extraction) but a comparison of their efficiencies in Mars relevant materials is missing. We have spiked the well characterised Mars analogue material JSC Mars-1 with a number of representative organic standards. Extraction of the spiked JSC Mars-1 with the three solvent methods provides insights into the relative efficiency of these methods and indicates how they may be used on future Mars missions. [ABSTRACT FROM AUTHOR]

Most bioanalytical LC-MS/MS methods are developed for determination of single drugs or classes of drugs, but a multi-compound LC-MS/MS method that can replace several methods could reduce both analysis time and costs. The aim of this study was to develop a high-throughput LC-MS/MS method for determination of the alcohol biomarker phosphatidylethanol 16:0/18:1 (PEth 16:0/18:1) and 33 other compounds from eight different drug classes in whole blood. Whole-blood samples were prepared by 96-well supported liquid extraction (SLE). Chromatographic separations were performed on a biphenyl core shell column with a mobile phase consisting of 10 mM ammonium formate, pH 3.1 and methanol. Each extract was analyzed twice by LC-MS/MS, injecting 0.4 μL and 2 μL, in order to obtain narrow and symmetrical peaks and good sensitivity for all compounds. Stable isotope-labeled internal standards were used for 31 of the 34 compounds. A 96-well SLE reversed phase LC-MS/MS method for determination of PEth 16:0/18:1 and 33 other compounds from eight different drug classes was developed and validated. By using an organic solvent mixture of isopropanol/ methyl tert-butyl ether (1:5, v:v), all compounds, including the polar and ampholytic compounds pregabalin, gabapentin and benzoylecgonine, was extracted by 96-well SLE. For the first time an LC-MS/MS method for the determination of alcohol biomarker PEth 16:0/18:1 and drugs and metabolites from several different drug classes was developed and validated. The developed LC-MS/MS method can be used for high-throughput analyses and sensitive determinations of the 34 compounds in whole blood. • Quantification of alcohol biomarker PEth 16:0/18:1 and 33 other compounds by LC-MS/MS • First method for quantification of PEth and drugs from several drug classes • Acidic, basic and ampholytic compounds determined by LC-MS/MS • First supported liquid extraction of pregabalin and gabapentin from blood • High throughput sample preparation by 96-well supported liquid extraction [ABSTRACT FROM AUTHOR]

• Determination of occupational exposure of VOC in the University community. • Development and validation of bioanalytical method for simultaneous exposure solvents. • Biological evaluation as tool for assessing occupational exposure. Occupational exposure to volatile organic compounds (VOC) might generate serious worker health damages. Therefore, biological monitoring is essential to evaluate exposure biomarkers from highly toxic chemicals, ensuring better attention to the worker health. In this study was developed and validated a bioanalytical method based on high-performance liquid chromatography coupled to photodiode array (HPLC-PDA) for the quantification of VOC biomarkers in urine samples from Federal University of Goias (UFG) workers. Samples were collected from 30 occupationally exposed subjects after application of a questionnaire survey. The following biomarkers hippuric acid, methyl-hippuric acid, mandelic acid, phenylglyoxylic acid and phenol were quantified, representing exposition to toluene, xylene, styrene, ethylbenzene, benzene and phenol solvents, respectively. Hippuric acid levels were found close to or above the reference values, although a subject had levels higher than preconized by Biological Limit Values (BLV) guideline of 4.0 mg/g creatinine. Five subjects had 3 and 4-methylhippuric acid ranging from 0.1 to 1.0 mg/g creatinine. These results indicate a moderate to high VOC exposure from UFG workers. Multivariate analysis generated four clusters and indicated that histotechnicians and graphic workers need especial attention on occupational VOC exposure. The results from this study reinforce the need for reliable methods able to the biological monitoring as an important tool for assessing occupational exposure. [ABSTRACT FROM AUTHOR]