pH of the mobile phase was adjusted to 2.7 using 50%
orthophosphoric acid. The mobile phase was degassed and filtered through 0.45um millipore filters.
* Group II: prophylaxis paste (Sultan; Topex, NJ, USA)+37%
orthophosphoric acid (Condicionador Dental Gel; Dentsply, Rio de Janeiro, Brazil)+primer and adhesive (Transbond XT; 3M Unitek, Monrovia, USA);
Celluloid bands were adapted on both surfaces, followed by etching the enamel for 30 s and the dentin for 15 s with 37%
orthophosphoric acid (Total-Etch 3M Scotchbond Universal Etchant, 3M ESPE, GmbH Dental Products, Neuss, Germany).
The gradient involves two mobile phases consisting of 10 g/ L solution of
orthophosphoric acid in water as solvent A and 10 g/L solution of
orthophosphoric acid in acetonitrile as solvent B.
(Shenyang, China); and
orthophosphoric acid was purchased from Zhiao Chemical Reagents Research Institute (Anshan, China).
After isolation of the fractured tooth, acid etching of the fractured fragment surfaces and maxillary right central incisor surfaces was done with 37%
orthophosphoric acid (3M ESPE) for 15 seconds.
The supernatant (2 mL) was mixed with two drops of
orthophosphoric acid and 4 mL of the Salkowski reagent (50 mL, 35% of perchloric acid, 1mL 0.5M Fe[Cl.sub.3] solution).
Anionic counterions (e.g., hexanesulphonic acid,
orthophosphoric acid, and trifluoroacetic acid) interact with the basic residues (i.e., arginine, lysine, and histidine) of a protein and with the protonated N-terminus.
We have used acidic medium by adding concentrated
orthophosphoric acid to get the good crosslinking action of glutaraldehyde.