title: High-Performance Liquid Chromatographic Analysis of Sarcosine as a Fluorescent Levofloxacin Derivative.
abstract: Sarcosine, N-methyl glycine, could be used as a biomarker for the diagnosis of prostate cancer. It exists in biosamples at low levels; therefore, sensitive methods are necessary for its detection. In this study, we developed a sensitive and selective method for the analysis of sarcosine, based on derivatizing sarcosine with a fluorescent reagent levofloxacin acyl chloride. The resulting derivative is highly responsive to a fluorimetric detector (λex = 290 nm, λem = 460 nm). The sarcosine derivative can be separated from its molecular isomers (α-l-alanine, α-d-alanine and β-alanine) on a hexyl-phenyl column by gradient elution using sodium acetate buffer (pH 3.8; 50 mM) and tetrahydrofuran as the mobile phase. The method showed a determination range of sarcosine in water over 44.5-1780.0 ng/mL (0.5-20.0 µM) and the limit of detection at 8.9 ng/mL (0.1 µM) (S/N = 3 with 20 µL injected). Intra- and inter-day precision (as % relative standard deviation) and accuracy (as % relative error) were all below 4.8%. Application of the method to the analysis of sarcosine in human urine proved feasible.
authors: Department of Pharmacy, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan School of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
authors: Tang-Chia
authors: TC
authors: Chung
authors: Department of Pharmacy, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung 812, Taiwan.
authors: Chien-Te
authors: CT
authors: Li
authors: School of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan kouhs@kmu.edu.tw.
authors: Hwang-Shang
authors: HS
authors: Kou
authors: School of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
authors: Hsin-Lung
authors: HL
authors: Wu
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D064704:Levofloxacin / Q000031:analogs & derivatives / Q000737:chemistry*; D057230:Limit of Detection; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012521:Sarcosine / Q000032:analysis* / Q000737:chemistry* / Q000652:urine; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D005456:Fluorescent Dyes; D064704:Levofloxacin; D012521:Sarcosine