PubMed · 6036220
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
D Bourne. 1967. Automatic exposure in routine work.. https://pubmed.ncbi.nlm.nih.gov/6036220/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
A rapid, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS-MS) method has been developed and validated for the simultaneous analysis of hydrocodone (HYC) and its metabolite hydromorphone (HYM) in human plasma. A robotic liquid handler and a 96-channel liquid handling workstation were used to aliquot samples, to add internal standard (I.S.), and to extract analytes of interest. A 96-well mixed-mode solid-phase cartridge plate was used to extract the analytes and I.S. The chromatographic separation was on a silica column (50 x 3 mm, 5-microm) with a mobile phase consisting of acetonitrile, water and trifluoroacetic acid (TFA) (92:8:0.01, v/v). The run time for each injection was 2.5 min with the retention times of approximately 2.1 and 2.2 min for HYC and HYM, respectively. The tandem mass spectrometric detection was by monitoring singly charged precursor-->product ion transition 300-->199 (m/z) for HYC, and 28-->185 (m/z) for HYM. The validated calibration curve range was 0.100-100 ng/ml, based on a plasma volume of 0.3 ml. The correlation coefficients were greater than or equal to 0.9996 for both HYC and HYM. The low limit of quantitation (LLOQ) was 0.100 ng/ml for both HYC and HYM with signal-to-noise ratio (S/N) of 50 and 10. respectively. The deuterated analytes, used as internal standards, were monitored at mass transitions 303-->199 (m/z) for HYC-d3 and 289-->185 (m/z) for HYM-d3. The inter-day (n= 17) precision of the quality control (QC) samples were < or = 3.5% RSD (relative standard deviation) for HYC and < or = 4.7% RSD for HYM, respectively. The inter-day accuracy of the QC samples were < or = 2.1% RE (relative error) for HYC and < or = 1.8% RE for HYM. The intra-day (n=6) precision and accuracy of the QC samples were < or = 2.6% RSD and < or = 3.0% RE for HYC, and < or = 4.7% RSD and < or = 2.4% RE for HYM. There was no significant deviation from the nominal values after a 5-fold dilution of high concentration QC samples by blank matrix. The QC samples were stable when kept at room temperature for 24-h or experienced three freeze-thaw cycles. The extraction recoveries were 86% for HYC and 78% for HYM. No detectable carryover was observed when a blank sample was injected immediately after a 2500 ng/ml sample that was 25-fold more concentrated than the upper limit of quantitation (ULOQ).
A charge-coupled device (CCD) was used to quantitatively detect isotope-labeled ligands bound to a protein microarray. Protein microarrays with protein dots, 10-50 microm in diameter, were fabricated on an aluminized Mylar film using an electrospray deposition technique. Proteins in dots were immobilized by cross-linking in glutaraldehyde vapor. After contact with solutions of isotope-labeled metabolites, the protein microarrays were washed, dried and placed face down onto the surface of a standard B/W video CCD chip with the protective window removed. We show here that such a simple inexpensive CCD detector can be used to quantify distribution of 14C and other radioactive isotopes on microarrays.
Concentrations of phosphate in natural waters are often below the detection limits of conventional nutrient autoanalyzers, by either gas-segmented continuous-flow analysis orflow injection analysis. A liquid waveguide capillary flow cell has been used to extend the sensitivity of a conventional autoanalyzer for the automated analysis of nanomolar concentrations of phosphate in natural waters. Total reflection of light can be achieved within the liquid core of the flow cell because the refractive index of a cell wall coated with Teflon 1600 is lower than that of water. This property allows the manufacturers to construct long liquid waveguide capillary flow cells in a helical, rather than a linear shape, with compact dimensions. A small sample volume is required because the internal volume of a 2-m long capillary flow cell is only approximately 0.5 cm3. Adaptation of this long flow cell to autoanalyzers significantly enhances the sensitivity of automated colorimetric analysis of phosphate with a molybdenum blue method, allowing for the accurate and precise determination of nanomolar concentrations of phosphate in natural waters. The advantages of this technique are a low detection limit (0.5 nM), a small sample volume (2 mL), high precision (2% at 10 nM levels), and automation for the rapid analysis of a large number of samples.