Dissolved oxygen measurement

When taking ex situ pH and dissolved oxygen measurements in a cup, for representative measurements stir standard solutions and samples with the probe in a consistent manner. 

Eliminate interferences for dissolved oxygen measurements by frequently replacing the membrane of the DO probe. 

Johnson MJ, Borkowski J, Engblom C (2000), Steam sterilizable probes for dissolved oxygen measurement, Biotechnol. Bioeng. 67 645-656. 

Olsson, G. Andrews, J.F. "Estimation and control of biological activity in the activated sludge process using dissolved oxygen measurements" Proc. IFAC Symp. Environmental Systems Planning, Design and Control, Kyoto, Japan, 1977. 

Fig. 7 Vertical distribution versus density (agy kg m 3) of temperature (T), salinity (S), transmission (Xmiss), dissolved oxygen measured with YSI oxygen sensor (02SB), dissolved oxygen measured by Winkler titration (02), hydrogen sulfide (H2S), phosphate (PO4), silicate (Si), nitrite (N02), ammonia (NH4), dissolved manganese (Mn diss), bivalent iron (Fe(II)), and trivalent iron (Fe(III)) at a station near the Bosporus (Cast 16, RV Knorr 172-05 cruise, April 04,2003). Concentrations of chemical parameters are in xM...

Redox mediators provide an alternative to dissolved oxygen measurements for monitoring of respiration or photosynthesis. The mechanism is based on the reducing activity of metabolising biological whole cells ... 

Although the one-layer model is an oversimplification of actual conditions, its application to the case where the oxygen partial pressure is allowed to change with time illustrates how electrode properties affect transient dissolved oxygen measurements. Pick s second law is needed to describe the unsteady-state diffusion in the membrane, and shows that the diffusion coefficient of the membrane directly determines how fast an electrode will respond to a step change in the oxygen partial pressure (Aiba et al., 1968 Lee and Tsao, 1979 Sobotka et al., 1982). Lee and Tsao (1979) showed mathematically that the electrode response time, for the one-layer model, depends on the electrode time constant defined as... 

Jones and Heindel (2007) compared the ki a values calculated from dissolved oxygen measurements using the models described in Eqs (4.19) and (4.20). As shown in Figure 4.7a, when experimental data. When < /k[ja (Figure 4.7b), Eqs (4.19) and (4.20) begin to show a difference in how they model the experimental data. When 1 jk a (Figure 4.7c), Eq. (4.20) provides a better model of the experimental data. Table 4.1 summarizes die calculated k a values using these two models for these three test conditions. 

Fill., filtration Evap., evaporation FI. det., fluorimetric detection SLE, solid-liquid extraction SEC, size-exclusion chromatography MD, microwave digestion LLE, liquid-liquid extraction Imm., immunoassay Phot, det., photometric detection FI. det., fluorimetric detection BOD, biological oxygen demand DOM, dissolved oxygen measurement SPE, solid-phase extraction Centr., centrifugation Mix., vortex mixing PCBs, polychlorinated biphenyls Pot. det., potentiometric detection TCP, 3,5,6-trichloro-2-pyridinol. 

A wireless capsule can provide an invasive method for the diagnosis of the GI tract. The sensor systems for a wireless capsule are composed of mechanical sensors for pressure and position measurement, chemical sensors for pH, conductivity, and dissolved oxygen measurement, and biosensors for bleeding and pathogens detection. In addition to the sensor systems, interface circuits for the sensors also play an important role for the development of low-noise and low-power sensor systems. As a result, wireless capsule requires the development of a reliable, miniaturized, and integrated sensor system with high sensitivity and resolution as well as a low noise, low cost, and a low-power interface circuit system. 

Johnson, M.J., Borkowski, J. and Engblom, C. Steam sterili-zable probes for dissolved oxygen measurement. Biotech. Bioengr., 457, 1964. 

Fig. 12.15 A Clark-type electrode for amperometric dissolved oxygen measurement, (see also Clark, L. C., Wolf, R., Granger, D. and Taylor, Z. (1953) J. Appl. Physiol, 6, 189.)...

Steel, R., and W. D. Maxon (1966). Dissolved oxygen measurements in pilot and production scale novobiocin fermentations, Biotechnol Bioeng., 8, 97-108. 

Figure 22.1 Luminescent silicone film containing an embedded Oj-sensitive Ru dye. Small disks are pierced for the film to be attached to the distal end of an optical liber for dissolved oxygen measurements in water. The indicator dye is excited with blue hght and emits red-orange luminescence, the intensity of which is quenched by the analyte gas entering the thin film and colliding with the photoexcited metal dye.

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