The research on formation enthalpy of phenanthroline monohydrate and its influence on the growth metabolism of E. coli by microcalorimetry

• Published in: Journal of thermal analysis and calorimetry Vol. 115; no. 3; pp. 2211 - 2217
• Main Authors: Xiao, Sheng-Xiong, Li, Ai-Tao, Li, Xu, Li, Chuan-Hua, Xiao, Hang-Ying, Huang, Shuang, Chen, Qiao-Shu, Ye, Li-Juan, Li, Qiang-Guo
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2014; Springer
• Subjects: Analytical Chemistry; Benzoic acid; Chemistry; Chemistry and Materials Science; Escherichia coli; Growth; Inorganic Chemistry; Measurement Science and Instrumentation; Organic acids; Physical Chemistry; Physiological aspects; Polymer Sciences; Standard enthalpy of formation; Hormesis effect; Thermokinetic parameters; Phenanthroline monohydrate
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-014-3642-5

A precision rotating-bomb combustion calorimeter (thermistor of which was constructed in the laboratory) was calibrated using benzoic acid with purity of 99.999 %. The combustion energy of phenanthroline monohydrate (phen·H 2 O) at 298.15 K was determined to be Δ c U m θ  = −(5,757.45 ± 2.53) kJ mol −1 . Then, the standard enthalpy of combustion and the standard enthalpy of formation of phen·H 2 O were calculated to be Δ c H m θ  = −(5,759.93 ± 2.53) kJ mol −1 and Δ f H m θ  = −(391.34 ± 2.98) kJ mo1 −1 , respectively. Particularly, the effect of phen·H 2 O on growth and metabolism of Escherichia coli ( E. coli ) was also determined by a TAM air isothermal calorimeter at 37 °C. The thermokinetic parameters, including maximum heat output power ( P max ), growth rate constant ( κ ), generation times ( t G ), inhibitive rate ( I ), and half inhibition concentration ( C I,50 ), were obtained. The results showed that phen·H 2 O possessed the bi-directional biological effect and Hormesis effect, which stimulated the growth of E. coli at lower concentration, but inhibited the growth at higher concentration. The half inhibition concentration C I,50 of phen·H 2 O was found to be 7.31 mg L −1 .