Study Of Dissolved Oxygen Sensing Film Based On Platinum Octaethylporphyrin As The Fluorescence Indicator

Oxygen is one of the most important elements involved in almost all living organisms and played a major role in energy generation and evolution. Therefore, sensing of oxygen has attracted particular attention as can be seen from a large numbers of publications in the past few decades. In this paper, novel optical oxygen sensing films were fabricated and applied in mixed air, water and organic solvents based on the fluorescence quenching of molecular oxygen to platinum octaethylporphyrin. The material of matrix and the characteristics of the sensing films were thoroughly studied. The main research contents are as follows:1.The oxygen sensing films were fabricated by choosing polystyrene(PS) as matrix, the characteristics of the sensing films were thoroughly studied. The experimental results showed that when the adding amount of PS was 10 g, the concentration and adding amount of sensing indicator Pt OEP were 1.0×10-2mol/L and 2.5ml, respectively, the oxygen sensing films had good fluorescence response to the oxygen in mixed air and the ratio of I0/I100 was 16.89. The relative standard deviation(RSD)(n=10) of fluorescence intensity in pure nitrogen and pure oxygen were 0.82% and 1.01%, respectively.In addition, sol-gel sensing films were also fabricated by choosing hydroxyl-terminated polydimethylsiloxane(HPDMS) and trimethoxysilane(MTOS) as co-precursors. The experimental results showed that when amount ratios of HPDMS:MTOS were 1:1, the concentration and adding amount of sensing indicator Pt OEP were 1.0×10-2mol/L and 3.0ml, respectively, the oxygen sensing films had good fluorescence response to the oxygen in mixed air and the ratio of I0/I100 was 17.16. The RSDs(n=10) of fluorescence intensity in pure nitrogen and pure oxygen were 0.65%å'Œ 0.91%, respectively, which indicated that the film had good reversibility and high sensitivity.2.The oxygen sensing films were fabricated by choosing cellulose acetate(CA) as matrix, The experimental results showed that when the adding amount of CA was 5g, also the concentration and adding amount of sensing indicator Pt OEP were 1.0×10-3mol/L and 2.0ml, respectively, the oxygen sensing films had good fluorescence response to the dissolved oxygen in water and the ratio of I0/I100 was 8.37. The RSDs(n=10) of fluorescence intensity in nitrogen saturated water and oxygen saturated water were 0.88% and 1.10%, respectively.A novel oxygen sensing film were fabricated when silica(Si O2), which was synthesized from the hydrolysis of siloxanes, were added to the system. The experimental results indicated that the sensing films had better fluorescence response to oxygen when 0.08 g of Si O2 was added. The RSDs(n=10) of fluorescence intensity in nitrogen saturated water and oxygen saturated water were 0.92% and 1.06%, the ratio of I0/I100 was 12.43. It indicated that the characteristics of sensing films were improved with Si O2 embedded.3.The oxygen sensing films were fabricated by choosing polyvinyl alcohol(PVA) as matrix, The experimental results showed that when the adding amount of PVA was 1.5g, the concentration and adding amount of sensing indicator Pt OEP were 1.0×10-3mol/L and 2.5ml, respectively, the oxygen sensing films had good fluorescence response to the dissolved oxygen in organic solvents. The ratio of I0/I100 were 12.25,7.45,9.41,12.57,8.96 and 7.04, respectively, when the sensing films were used to detect dissolved oxygen in 1,3-butanediol, chloroform, toluene, DMF, glycerol and hexane.The fluorescence intensity of PVA sensing films had increased when 0.1g of zinc oxide(Zn O) were added to the system. The ratio of I0/I100 was 24.07,18.72,18.84,18.46,9.96 and 12.55, respectively, when the sensing films were used to sense dissolved oxygen in 1,3-butanediol, chloroform, toluene, DMF, glycerol and hexane. The RSDs(n=10) were 0.17%,0.20%,0.22%,0.15%,0.28% and 0.19%.