This application note describes the analysis of selected designer drugs in urine after a very simple, fast and non-selective dilution step. Besides identification of the analytes by two or three MRM transitions, an information dependent acquisition (IDA) approach was used for automatically triggering enhanced product ion (EPI) scans after detection with one MRM transition per analyte. EPI spect...

Dual-gradient capillary electrochromatography (DG-CEC) was developed to provide superior performance with regard to the separation of ionized analytes; in this method, both the eluent composition and the applied voltage are varied during the separation procedure. As for the gradient in the eluent composition, a shift in the pH is employed to control not only the electrophoretic mobility, but al...

The identification of species is a fundamental problem in analytical chemistry and biology. Mass spectrometers identify species by their molecular mass with extremely high sensitivity (<10-24 g). However, its application is usually limited to light analytes (<10-19 g). Here we demonstrate that by using nanomechanical resonators, heavier analytes can be identified by their mass and stiffness. Th...

CONTEXT Harmonization and standardization of results among different clinical laboratories is necessary for clinical practice guidelines to be established. OBJECTIVE To evaluate the state of the art in measuring 10 routine chemistry analytes. DESIGN A specimen prepared as off-the-clot pooled sera and 4 conventionally prepared specimens were sent to participants in the College of American Pa...

Multiplexed or simultaneous detection of multiple analytes is a valuable tool in many analytical applications. However, complications caused by the presence of interfering compounds in a sample form a major drawback in existing molecular sensor technologies, particularly in multi-analyte systems. Although separating analytes through extraction or chromatography can partially address the problem...

The techniques of membrane extraction permit the application of classical liquid-liquid extraction (LLE) chemistry to instrumental and automated operation. Various shortcomings of LLE are overcome by membrane extraction techniques as they use none or very little organic solvents, high enrichment factors can be obtained and there are no problems with emulsions. A three phase SLM system (aq/org/a...

To evaluate the long-term stability of a new liquid quality-control serum ("Decision", Beckman Instruments, Inc.) stabilized with ethylene glycol (330 mL/L), we analyzed it for 22 commonly measured analytes during storage at 2--8 degrees C for 24 days or -15 to -20 degrees C for 55 weeks. Three separate laboratories replicated the analyses, using various analytical methodologies. The data were ...

We performed an immunoassay evaluation for various analytes on a fully automated random-access analyzer, the Technicon Immuno 1 system from Bayer Corp. This system involves latex agglutination, magnetic separation sandwich, and magnetic separation competitive immunoassay configurations. The evaluated analytes were thyrotropin (TSH), triiodothyronine, thyroxine, free thyroxine, follitropin, lutr...

The sample treatment/preparation steps involve any operation and manipulation of the samples prior to instrumental determination of the target compounds [1−3]. This is a critical step in the analytical process because the concentration of target analytes in the samples is frequently too low for quantification. Thus, the first step of the preparation protocol involves the exhaustive extraction/c...