Background. Peptides are important components of foods mainly due to their biological activity. The basic method of their identification is reversed phase high-performance liquid chromatography coupled with electrospray-ionization mass spectrometry (RP-HPLC-ESI-MS). Retention time (tR) prediction in silico is very helpful in analysis of multicomponent peptide mixtures. One of problems associate...

In this study, a lab-scale membrane bioreactor (MBR) was operated for a period of more than 10 months to determine the biokinetic coefficients of the system under the hydraulic retention times (HRT) of 20, 15 and 10 hrs and sludge retention times (SRT) of 5-20 days. The results revealed that the biological removal efficiency of styrene and ethylbenzene at a solid retention time of 20 day and a ...

Two retention time locked methods for the analysis of essential oil compounds are described. The first method is a gas chromatography/flame ionization detector method using a 50 m × 320 μm id × 1.05 μm HP-5 column. The second method is a gas chromatography/mass spectrometry method using a 30 m × 250 μm id × 0.25 μm HP-5MS column. Retention times of approximately 400 essential compounds were mea...

It has been proved mathematically that there exists an identity between the various published methods for determining the hold-up times in gas chromatography. All of these methods are based on the equation: ln t'(R) = ln (t(R) - t(M)) = a + bZ, where t(R), t'(R), and t(M) are retention times, adjusted retention times, and hold-up times, respectively; a and b are coefficients that depend on the ...

BACKGROUND Previous evaluations of HPLC as a tool for detection of hemoglobin variants have done so within newborn-screening programs and/or by use of stored samples. We describe a 32-month prospective study in a clinical diagnostic laboratory in which we evaluated the imprecision of HPLC retention times and determined the retention times for hemoglobin variants seen in a multiethnic setting. ...