Extraction of steroids from urine with C18 solid-phase extraction cartridges results in an extract containing impurities. If, during the extraction of hydrolyzed urine, an amino (NH2) column is placed in series with the C18 column, then one obtains a sample that is sufficiently clean for gas-chromatographic analysis. Analytical recovery of dehydroepiandrosterone from urine is considerably decre...

A tidal bore is a series of waves propagating upstream as the tidal flow turns to rising. It forms during the spring tide conditions when the tidal range exceeds 5–6 m and the flood tide is confined to a narrow funnelled estuary with low freshwater levels. A tidal bore is associated with a massive mixing of the estuarine waters that stirs the organic matter and creates some rich fishing grounds...

The gas chromatography-flame ionization detector equipped with a higher polarity column (i.e., SP-2560) has often been used for the quantification of trans-fatty acids in food. In particular, AOCS Ce 1h-05, the official method of the American Oil Chemists' Society (AOCS), is a highly effective method to separate the isomers of trans-fatty acids. In this study, the resolution behavior and the re...

A technique for rescue task in bore well environment has been proposed. India is facing a distressed cruel situation where in the previous years a number of child deaths have been reported falling in the bore well. As the diameter of the bore well is quiet narrow for any adult person and the lights goes dark inside it, the rescue task in those situations is a challenging task. Here we are propo...

The character of a brass musical instrument is primarily dependent on its bore profile. Many historic brass instruments are so constructed that substantial parts of the air column are inaccessible to direct measurement. This paper discusses the factors involved and reports recent advances in the use of pulse reflectometry for bore reconstruction, in particular compensation for losses and allowa...

isolated five known iridoids glycosides (scrophuloside a, harpagoside b, 5-hydroxyloganin, 8-o-acetylharpagide and 6-o-methyl,1-glucopyranosyl catalpol ),one phenyl ethanoid glycoside (verbascoside) and a phenyl ethanol amine (2-(4-chlorobenzyl amino) ethanol ) compound from the methanolic extract of aerial parts of scrophularia oxysepala using by high performance liquid chromatography based on...

The use of the Agilent LC/MSD TOF, an orthogonal-axis time-of-flight (oa-TOF) mass spectrometer, equipped with an atmospheric pressure chemical ionization (APCI) source, is described for the analysis of four anabolic steroids and one internal standard, in urine extracts at a 1–2 ng/mL concentration. The high degree of mass accuracy (<3 ppm) of the TOF instrument allows for both excellent confir...

A highly sensitive analytical procedure is described for determining thiodiglycol in groundwater. Samples are initially fortified with 3,3'-thiodipropanol (surrogate), then both species are extracted using sequential solid-phase extraction with both C18 and Ambersorb 572 columns. The C18 column, which removes extraneous groundwater components, is discarded; the Ambersorb 572 column is dried tho...

Objective: To develop an ultraperformance liquid chromatography (AcquityTM UPLC) method for simple, fast, accurate and simultaneous determination of nitrite and nitrate ions as stable forms of nitric oxide (NO) production in rat plasma. Methods: The ion-pairing AcquityTM UPLC method with reverse phase BEH C18 column was used along with photodiode array (PDA) UV-Vis detector to separate and dete...

CHEMISTRY General methods. All solvents and reagents were purchased from commercial sources and used without further purification. The compounds were spotted on silica TLC plates (Merck, Si 60 , F254), visualized under UV-light at 254 nm or iodine over silica. Purification of the compounds for biological tests was performed on a Waters 2767 system equipped with a photodiode array and an ESI mas...