Protein or peptide sample losses could accompany all steps of the proteomic analysis workflow. We focused on suppression of sample adsorptive losses during sample storage in autosampler vials. We examined suppression capabilities of six different sample injection solutions and seven types of autosampler vial surfaces using a model sample (tryptic digest of six proteins, 1 fmol per protein). While the vial material did not play an essential role, the choice of appropriate composition of sample injection solution reduced adsorptive losses substantially. The combination of a polypropylene vial and solution of poly(ethylene glycol) (PEG) (0.001%) or a mixture of high concentrated urea and thiourea (6 M and 1 M) as injection solutions (both acidified with formic acid (FA) (0.1%)) provided the best results in terms of number of significantly identified peptides (p < 0.05). These conclusions were confirmed by analyses of a real sample with intermediate complexity (in-gel digest from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)). Addition of PEG into the real sample solution proved to prevent higher losses, concerning mainly hydrophobic peptides, during up to 48 h storage in the autosampler in comparison with a formic acid solution and even with a solution of highly concentrated urea and thiourea. Using PEG for several months was not accompanied by any adverse effect to the liquid chromatography system.

• MeSH
• adsorpce MeSH
• chromatografie kapalinová normy   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• formiáty MeSH
• hydrofobní a hydrofilní interakce MeSH
• močovina MeSH
• odběr biologického vzorku normy   MeSH
• peptidové fragmenty izolace a purifikace   normy   MeSH
• polyethylenglykoly MeSH
• proteiny chemie   MeSH
• průtoková injekční analýza normy   MeSH
• thiomočovina MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• formiáty MeSH
• formic acid MeSH Prohlížeč
• močovina MeSH
• peptidové fragmenty MeSH
• polyethylenglykoly MeSH
• proteiny MeSH
• thiomočovina MeSH

This report introduces a fully automated flow system for drug-dissolution studies based on the coupling of the sequential injection analysis (SIA) technique with a conventional dissolution apparatus. The methodology described was used for monitoring of dissolution profiles of prazosin hydrochloride (PRH) in pharmaceutical formulation. The very sensitive fluorimetric detection of PRH was performed at lambda(ex)=244 nm (lambda(em)>or=389 nm). Under the optimal conditions, the calibration curve was linear over the range 0.02-2.43 mg x l(-1) of PRH with R.S.D. 1.89, 1.23, and 1.80% (n=10) when determining 0.02, 1.22, and 2.43 mg x l(-1) of PRH in standard solutions, respectively. Equation of the calibration curve was calculated giving the following values: F=4.108 c-3.9 (n=6), r=0.9996. Detection limit was calculated 0.007 mg x l(-1) of PRH. The dissolution test of Deprazolin tablets was programmed for 60 min, with a continuous sampling rate of 70 h(-1) under conditions required by USP 26. Results obtained by SIA technique compared well with HPLC standard method.

• MeSH
• prazosin analýza   chemie   normy   MeSH
• průtoková injekční analýza metody   normy   MeSH
• řízení kvality MeSH
• rozpustnost účinky léků   MeSH
• spektrofotometrie ultrafialová metody   normy   MeSH
• tablety MeSH
• vysokoúčinná kapalinová chromatografie metody   normy   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• prazosin MeSH
• tablety MeSH