D by lipase in organic media. To decide the production yield from the lipase- catalysed esterification between palmitate acid and isoascorbic acid, the wave complete scan was carried out in the diode array detector from 180 nm to 1000 nm to choose the optimal figuring out wavelength for the samples. Benefits showed that the absorbance of isoascorbic acid and isoascorbyl palmitate had the maximum level when the wavelength was set as 254 nm. Hence the HPLC analysis was performed in the wavelength of 254 nm. Figure two showed the HPLC chromatograph from the reaction option samples with ultraviolet detector. Isoascorbic acid and isoascorbyl palmitate peaks separated nicely together with the retention occasions of 1.44 and 7.36 min, respectively. The mass spectra of LC-MS indicated that the sample had the mass-to-charge ratios from the molecular ion peak (M -H) of 413.35 and (2M – H) of 827.00, while D-isoascorbyl palmitate ought to possess a mass-to-charge ratio of 414 (M), which proved that the synthesized sample is D-isoascorbyl palmitateHOOO OHOH HO OH+HOErythorbic acidPalmitic acidImmobilized lipase NovozymO O O OH O HO H OHErythorbly palmitateFigure 1 The scheme of lipase-catalysed synthesis of D-isoascorbyl palmitate.+H2OSun et al. Chemistry Central Journal 2013, 7:114 http://journal.chemistrycentral/content/7/1/Page 3 ofFigure 2 HPLC-PDA chromatogram for the elements obtained in the immobilized lipase-catalysed esterification involving isoascorbic acid and palmitic acid.Structural characteristic evaluation of the synthesized D-isoascorbyl palmitateThe FT-IR spectrum for the sample isoascorbyl palmitate was presented in Figure 3. The band inside the area of 3423 cm-1 is on account of the hydroxyl stretching vibration. The band within the region of 2930 cm-1 and 2850 cm-1 are on account of C-H stretching vibration in CH2 and 1711 cm-1 is the absorption of C=O stretching vibration. Absorption at 1659 cm-1 was typical for dual bond C = C in isoascorbic acid. The band of 1470 cm-1 was characteristic absorption of CH3. The characteristic absorption at 1341 cm-1, 1225 cm-1, 1151 cm-1, 1110 cm-1 and 1054 cm-1 within the FT-IR spectrum was indicative of C-O-C linkage within the isoascorbyl palmitate whilethe absorption at 721 cm-1 also indicated the presence of linked palmitic acid. 1 H, 13C NMR spectra were determined as follows (Figure 4), 1H NMR (400 MHz,DMSO-d6): (ppm):11.Eflornithine 258 (s,1H,-OH), 8.Dofetilide 467 (s,1H,-OH), 5.PMID:26446225 577(s,1H,-OH), 4.739 (d,1H, -CH,J=1.6 Hz), 4.017(m,3H,-OCH2-OH), two.279 (t,2H,-CH2CO, J=7.6Hz), 1.504 (t,2H,-CH2-,J=6.eight Hz), 1.236 (m,2H,12-CH2-), 0.855 (t,3H,-CH3,J=7.2 Hz). 13 C NMR(400MHz,DMSO-d6): (ppm):(173.21 (C1=O), 170.60 (C-1’=O), 152.96 (C-2), 118.74 (C-3), 76.62 (C-4), 68.07(C-5), 63.84(C-6), 34.11 (C-2′), 33.80 (C-3′), 31.7728.94 (C-4′-C12′), 24.95 (C-13′), 24.81 (C-14′), 22.57 (C-15′), 14.39 (C-16′).Figure 3 FT-IR spectra of isoascorbyl palmitate synthesized by lipase.Sun et al. Chemistry Central Journal 2013, 7:114 http://journal.chemistrycentral/content/7/1/Page 4 ofFigure four 1H (a) andC NMR (b) spectra of isoascorbyl palmitate synthesized by lipase in present study (400 MHz, DMSO-d6).The 13C NMR spectrum of isoascorbyl palmitate showed the carbonyl group at C-1 and double bonds amongst C-2 and C-3 in isoascorbic moiety were intact which indicated that the enzymatic reaction happened in other position. The C-6′ signal at 65.6 ppm inside the synthesized isoascorbylester had a down-field shift of three.9 ppm in comparison with that of isoascorbic acid (61.7 ppm). These results proved the pre.