Concentrations of halogenated volatile organic compounds VOCs were determined by gas chromatography GC with an electron-capture detector GC-ECD and by gas chromatography with mass spectrometry GC-MS in 109 groundwater samples from five study areas in the United States. In each case, the untreated water sample was used for drinking-water purposes or was from a monitoring well in an area near a d...

A highly sensitive and simple method for the analysis of chlorothalonil was presented using a liquid chromatograph/mass spectrometer equipped with an atmospheric pressure photoionization (APPI) source. Chlorothalonil is one of the most extensively used fungicides. The major degraded product of chlorothalonil, 4-hydroxy-2,5,6-trichloroisonaphthonitrile (4OH-TPN), was also quantified with sensiti...

This study intended to develop a robust and sensitive method for simultaneous determination of polycyclic musks (HHCB and AHTN) and nitro musks (musk xylene (MX) and musk ketone (MK)) in water samples using optimized solid-phase extraction (SPE) by gas chromatography and mass spectrometry (GC-MS). The SPE procedure was optimized in terms of selections of SPE cartridge, sample pH, elution proces...

It is generally assumed that correcting chromatic aberrations in imaging requires optical elements. Here, we show by allowing the phase image plane to be a free parameter, it possible correct variation of focal length over an extremely large bandwidth, from visible (Vis) longwave infrared (LWIR) wavelengths using single diffractive surface, i.e., flat lens. Specifically, designed, fabricated an...

A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation reagent and a microfabricated planar glass micro-reactor...

Analytical method for the determination of six flame retardants (FRs) from two groups was proposed. These groups included the brominated flame retardants (BFRs) 3,3',5,5'-tetrabromobisphenol A (TBBPA), 1,2,5,6,9,10-hexabromocyclododecane (HBCD) and tetrabromophthalic anhydride (TBPA) and triester organophosphate flame retardants (OPFRs) tris(2,3-dibromopropyl) phosphate (TBPP), ethylhexyl diphe...

PURPOSE The purpose of this study was to investigate the possible radioactive potential of zirconium dioxide (ZrO2) dental ceramics. Such information is necessary since they became an integral part of routine prosthetic rehabilitations and devoid of scientific information about their radioactivity creates some concern in the dental community. METHODS Four different types of commercial ZrO2 ce...

A continuous wave (CW) quantum cascade laser (QCL) based absorption sensor system was demonstrated and developed for simultaneous detection of atmospheric nitrous oxide (N(2)O), methane (CH(4)), and water vapor (H(2)O). A 7.73-µm CW QCL with its wavelength scanned over a spectral range of 1296.9-1297.6 cm(-1) was used to simultaneously target three neighboring strong absorption lines, N(2)O at ...