Acetyl Benzene Sulfonyl Fluoride As The Amino Acid Derivative Reagent Performance And Its Application In Capillary Electrophoresis Separation And Detection Of Amino Acids

1. A new method for the synthesis of p-acetamidobenzenesulfonyl fluoride and its characteristics for labeling amino acids.An ultraviolet (UV) labeling reagent named p-acetamidobenzenesulfonyl fluoride (PAABS-F) was synthesized in our laboratory for labeling and determination of amino acids by capillary electrophoresis (CE) with diode-array detector (DAD). The molar absorptivity of PAABS-F is 3.00×104 L·mol-1·cm-1 which is nearly 3 times bigger than any other UV labeling reagents. PAABS-F is very stable, cheap, synthesized easily, nontoxic, and can react very fast with both primary and secondary amino acids in the facile conditions to give the corresponding derivatives, which exhibits excellent sensitivity, stability and high derivative yield. No by-products were found in amino acid derivatives when they were stored at room temperature under natural daylight for at least 7 days. Amino acids from both standard solution and real samples were successfully reacted with this new UV labeling reagent to form highly UV absorption derivatives. The labeled 20 standard amino acids are effectively separated by CE and detected by DAD. The mass detection limits (S/N = 3) were ranged from 59.3 fmol for L-tryptophan to 1.70 pmol for L-histidine.2. A simple method for the quick separation of amino acids in wines with a new labeling reagent in Capillary ElectrophoresisA simple method has been developed for the quick separation of amino acids with a new ultraviolet (UV) labeling reagent named p-acetamidobenzenesulfonyl fluoride (PAABS-F) by capillary electrophoresis (CE). 20 standard amino acids were successfully labeled with PAABS-F at 35°C for 30 minutes, and consequently separated by CE in a buffer system containing 20 mmol/L borate, 126 mmol/L SDS, 8 mmol/Lβ-CD and 20 mmol/L sodium chlorate. The separation results showed thatβ-CD is an effective additive for CE separation of ionic analytes. Under optimal conditions, 20 amino acid standards were separated in 16 min. Using this established simple method, amino acids in beers and yellow wine were successfully determined.3. Enhanced Micellar electrokinetic capillary chromatographic separation of amino acids through control of electroosmotic flow by the buffer cationThe effect of divalent cation (Mg2+) and 3 monovalent cations ( Na+, Li+ and K+ ) are estimated as buffer additives to reduce electroosmotic flow (EOF) to facilitate the micellar electrokinetic capillary chromatographic (MEKC) separation of p-acetamidobenzenesulfonyl fluoride (PAABS-F) derivatives of 20 standard amino acids. It is found out that as the cation concentration increases EOF decreases and reduction of EOF follows the order Mg2+ >K+>Na+> Li+. Taking migration time, resolution and peak shape of the derivatives into account, it is best for Na+ as the buffer additive though Na+ must be used at a higher concentration than either K+ or Mg2+.4.Chiral separation of D,L-amino acids by capillary electrophoresisA simple method for the chiral separation of amino acid enantiomers using p-acetamidobenzenesulfonyl fluoride (PAABS-F) as precolumn derivation reagent by micellar electrokinetic chromatography (MEKC) with diode array detector at 254 nm has been established. Cyclodextrin (CD) and sodium deoxycholic (SDC) were used as binary chiral selectors. It was found that the optimum molar ratio of CD to SDC is 1:1.75 and the best running buffer is 80 mmol/L borate at pH=9.3. Under these optimal conditions, 10 pairs of amino acid enantiomers were successfully resolved.