,Sonty Limmtvpirt, Chutim Limmtvpirt,

aFaculty of Pharmacy,Silpakorn University,Nakhon Pathom 73000,Thailand

bPharmaceutical Biopolymer Group(PBiG),Faculty of Pharmacy,Silpakorn University,Nakhon Pathom 73000, Thailand

cFaculty of Pharmacy,Siam University,Bangkok 10160,Thailand

Determination of mono-,di-,and trilaurin in modifed coconut oil using HPLC–ELSD

Juthaporn Ponphaiboona,b,Sirikarn Pengonc, Amornrat Chaidedgumjorna,Sontaya Limmatvapirata,b, Chutima Limmatvapirata,*

aFaculty of Pharmacy,Silpakorn University,Nakhon Pathom 73000,Thailand

bPharmaceutical Biopolymer Group(PBiG),Faculty of Pharmacy,Silpakorn University,Nakhon Pathom 73000, Thailand

cFaculty of Pharmacy,Siam University,Bangkok 10160,Thailand

A R T I C L E I N F O

Article history:

Available online 25 November 2015

Monolaurin

Dilaurin

Trilaurin

Modifed coconut oil

HPLC–ELSD

Modifed coconut oil(MCO)enriched with monolaurin(ML)was prepared by the glycerolysis of coconut oil[1].Glycerolysis converts dilaurin(DL)and trilaurin(TL)into ML,the lauric acid monoglyceride.ML has been found to have antiviral,antibacterial and antifungal activities[2].According to the antimicrobial activity,the glyceride composition of MCO was determined.The concentrations of ML,DL,andTL in MCO were analyzed using high-performance liquid chromatography–evaporative light scattering detector(HPLC–ELSD).

The HPLC–ELSD analyses were performed using an HPLC 1200 series equipped with an ELSD and a ZORBAX Eclipse Plus C18column(4.6×250 mm,5 μm)from AgilentTechnologies Inc.The mobile phase consisted of 0.01%(v/v)acetic acid in acetonitrile (solvent A)and acetone(solvent B)and was degassed by ultrasonic bath prior to use.The HPLC column temperature was 25°C. The mobile phase was maintained at a fow rate of 1.0 ml/min with the following gradient condition:solvent A:solvent B(90:10 v/v)from 0 to 5 min to solvent A:solvent B(70:30 v/v)from 5 to 10 min to solvent A:solvent B(50:50 v/v)from 10 to 15 min to solvent A:solvent B(30:70 v/v)from 15 to 20 min to solvent A:solvent B(20:80 v/v),and then held for 10 min.The equilibration time between runs was 10 min and the injection volume used was 10 μl.The temperature of the nebulization was set at 40°C and nitrogen gas was 3.5 bar.

The ELSD were capable of a linear response(R2>0.9995)independent of individual glyceride molecular structures atconcentrations between～0.02 and 0.40 mg/ml.Intra-and interday reproducibility(n=5)were evaluated under the optimized conditions.The relative standard deviations for glycerides were less than 2.45%.The detection limits(LODs)and the quantifcation limits(LOQs)were lower than 0.054 and 0.162 mg/ml, respectively.The effciency of this method,measured through the recoveries,was higher than 96.06%.The elution order of the standards was ML

Fig.1–Chromatograms of ML,DL and TL standards.

HPLC using a simple gradient and ELSD is an appropriate technique for the determination of ML,DL,andTL in MCO.The established method is sensitive,precise,rapid,and can be applied for routine analyses.

Acknowledgements

This research was kindly supported by the Thailand Toray Science Foundation,the Silpakorn University Research and Development Institute and the Faculty of Pharmacy,Silpakorn University.

R E F E R E N C E S

[1]Pengon S.Preparation and application of coconut oil and its modifed forms as alternative antimicrobial agents[Ph.D. dissertation].Thailand:Graduate School,Program of Pharmaceutical Engineering(International Program), Silpakorn University;2014,51.

[2]Kabara JJ.Medium-chain fatty acids and esters.In:Davidson PM,Branen AL,editors.Antimicrobials in foods.New York: Marcel Dekker;1993.

*E-mail address:limmatvapirat_c@su.ac.th.

Peer review under responsibility of Shenyang Pharmaceutical University.

http://dx.doi.org/10.1016/j.ajps.2015.11.025

1818-0876/?2016 Production and hosting by Elsevier B.V.on behalf of Shenyang Pharmaceutical University.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).