title: Efficacy of head space solid-phase microextraction coupled to gas chromatography-mass spectrometry method for determination of the trace extracellular hydrocarbons of cyanobacteria.
abstract: Hydrocarbons are widespread in cyanobacteria, and the biochemical synthetic pathways were recently identified. Intracellular fatty alka(e)nes of cyanobacteria have been detected by liquid-liquid extraction (LLE) coupled to gas chromatography-mass spectrometry (GC/MS). However, whether fatty alka(e)nes can be released to cyanobacterial culture media remains to be clarified. This work develops a sensitive method for analyzing the trace level of extracellular hydrocarbons in cyanobacterial culture media by head space solid-phase microextraction (HS-SPME) coupled to GC/MS. Headspace (HS) extraction mode using polydimethylsiloxane fiber to extract for 30min at 50°C was employed as the optimal extraction conditions. Five cyanobacterial fatty alka(e)nes analogs including pentadecene (C15:1), pentadecane (C15:0), heptadecene (C17:1), heptadecane (C17:0), nonadecane (C19:0) were analyzed, and the data obtained from HS-SPME-GC/MS method were quantified using internal standard peak area comparisons. Limits of detection (LOD), limits of quantitation (LOQ), linear dynamic range, precisions (RSD) and recovery for the analysis of extracellular fatty alka(e)nes of cyanobacteria by HS-SPME-GC/MS were evaluated. The LODs limits of detection (S/N = 3) varied from 10 to 21 ng L-1. The correlation coefficients (r) of the calibration curves ranged from 0.9873 to 0.9977 with a linearity from 0.1 to 50 μg L-1. The RSD values were ranging from 7.8 to 14.0% and from 4.0 to 8.8% at 1.0 μg L-1 and 10.0 μg L-1 standard solutions, respectively. Comparative analysis of extracellular fatty alka(e)nes in the culture media of model cyanobacteria Synechocystis sp. PCC 6803 demonstrated that sensitivity of HS-SPME-GC/MS method was significantly higher than LLE method. Finally, we found that heptadecane can be released into the culture media of Synechocystis sp. PCC 6803 at the later growth period.
authors.affiliation: Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China. Electronic address: guanwn@qibebt.ac.cn.
authors.forename: Wenna
authors.initials: W
authors.lastname: Guan
authors.affiliation: Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhu
authors.affiliation: College of Chemical Science and Engineering, Qingdao University, No.308 Ningxia Road, Qingdao 266071, China.
authors.forename: Yuejie
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Chemical Science and Engineering, Qingdao University, No.308 Ningxia Road, Qingdao 266071, China. Electronic address: Zhangzy@qdu.edu.cn.
authors.forename: Zhongyi
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Qingdao Zhenzheng Analytical Instruments Co., Ltd., No 89 Changcheng Road, Qingdao 266109, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China.
authors.forename: Fali
authors.initials: F
authors.lastname: Bai
mesh_terms: D018929:Cell Culture Techniques; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006838:Hydrocarbons / Q000032:analysis / Q000378:metabolism*; D052617:Solid Phase Microextraction / Q000379:methods*; D046939:Synechocystis / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003470:Culture Media; D006838:Hydrocarbons
keywords: Cyanobacteria; Extracellular hydrocarbons; Gas chromatography–mass spectrometry (GC–MS); Solid-phase microextraction