title: Fluorescent labelling of ciprofloxacin and norfloxacin and its application for residues analysis in surface water.
abstract: Sensitivity enhancement for residue analysis of ciprofloxacin and norfloxacin in surface water was performed by liquid chromatography with fluorescent detection (LC-FD). Labelling of both drugs were studied with fluorescent probes (e.g. Nile blue perchlorate (NBP) and 4- (N,N-Dimethylaminosulfonyl)-7-(N-chloroformylmethyl-N-methylamino)-2,1,3-benzoxadiazole (DBD-COCl). Factors affecting the derivatization (e.g. stoichiometric ratios, reaction time and base catalysts) were optimized. The derivatization was achieved in 15min using a stoichiometric ratio between the substrate and DBD-COCl of 1:3, whereas NBP gave unsatisfactory results. Separation of the derivatives by LC was achieved (resolution (RS) > 1.8) on a C8 column using a mobile phase consisting of 50mM formic acid and acetonitrile (ACN) (68:32% v/v) in 20min. The method was linear (r(2) > 0.99) in a range of 200-2,000µg/L, precise (%RSD < 9.17) and accurate (%recovery of 102.5-122.2%) for the determination of the derivatives. The uses of fluoroquinolone molecularly imprinted polymer in conjunction with hydrophilic-lipophilic balance sorbents demonstrated an efficient procedure for sample pre-concentration and clean-up for water sample resulting in the improved percent recovery. Applications of the proposed method was shown in surface water samples in Thailand.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayuddhaya Rd., Rajathevee, Bangkok 10400, Thailand.
authors.forename: Brompoj
authors.initials: B
authors.lastname: Prutthiwanasan
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayuddhaya Rd., Rajathevee, Bangkok 10400, Thailand.
authors.forename: Chutima
authors.initials: C
authors.lastname: Phechkrajang
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayuddhaya Rd., Rajathevee, Bangkok 10400, Thailand. Electronic address: leena.sun@mahidol.ac.th.
authors.forename: Leena
authors.initials: L
authors.lastname: Suntornsuk
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002939:Ciprofloxacin / Q000032:analysis* / Q000737:chemistry*; D004784:Environmental Monitoring / Q000379:methods*; D005456:Fluorescent Dyes; D005618:Fresh Water / Q000737:chemistry*; D009643:Norfloxacin / Q000032:analysis* / Q000737:chemistry*; D010069:Oxadiazoles; D015203:Reproducibility of Results; D013785:Thailand
chemical_list: D005456:Fluorescent Dyes; D010069:Oxadiazoles; C089192:4-(N-chloroformylmethyl-N-methyl)amino-7-N,N-dimethylaminosulfonyl-2,1,3-benzoxadiazole; D002939:Ciprofloxacin; D009643:Norfloxacin
keywords: Ciprofloxacin; Fluorescent labelling; Fluoroquinolone; Norfloxacin; Residue analysis