Phosphate monitoring

EPA. 1978. Environmental Protection Agency. Preliminary report on aryl phosphate monitoring with attachment. Intra-Agency memorandum from A.B. Crockett, Environmental Monitoring and Support Laboratory, Office of Research and Development to M.P. Halper, Monitoring and Data Support. 

IVPB, intravenous piggyback K, potassium Na, sodium P04, phosphate. Monitor serum K closely. 

Figure 18 Quenching of PBAC (2.6 jjlM) monomer emission by KI in the absence ( ) and in the presence ( ) of 0.001% phosphate, monitored at 378 nm ( ex = 340 nm). (From Ref. 20. Copyright 1993 Elsevier Publications.)...

It is common for both pH and ortho-phosphate monitoring at water treatment plants to be undertaken by on-line monitors, often hnked via telemetry to a central control facility. 

Some operators use an on-line ortho-phosphate monitor to record the phosphate concentrations achieved by dosing. It is important that sampling lines are located at a suitable down-stream position where mixing of the chemical is complete. The monitors typically sample every 15 minutes and use a colorimetric test procedure involving test reagents, which should be kept in date. 

The signal from the phosphate monitor can be used to automatically trim dosing but experience in the UK has varied and many operators only use the monitors for local information, linking to alarm systems, validating performance and for water quality reporting. 

An on-line phosphate monitor can be used, with sampling after the phosphate injection point. Results can be displayed both locally and at a central control point (via telemetry). If preferred, the results can be used to control the dosing pump. 

Figure 8.4 Examples of phosphate monitoring results (from Hayes et al., 2008)...

The phosphate monitors in use can experience problems, as a result of chemical reagent quality and monitor reliability. In the Wales case study, this prompted a comprehensive review leading to site-specific improvements where necessary and the adoption of a minimum acceptable criterion for monitoring that the standard deviation of results should not exceed 0.2 mgA (P). The range in dosing performances that were experienced is illustrated by Figure 8.4, but were soon improved where necessary it was found that the application of ortho-phosphate at a constant or near constant dose is necessary to maximise its effect. 

A final requirement for a chemical kinetic method of analysis is that it must be possible to monitor the reaction s progress by following the change in concentration for one of the reactants or products as a function of time. Which species is used is not important thus, in a quantitative analysis the rate can be measured by monitoring the analyte, a reagent reacting with the analyte, or a product. For example, the concentration of phosphate can be determined by monitoring its reaction with Mo(VI) to form 12-molybdophosphoric acid (12-MPA). 

Deming and Pardue studied the kinetics for the hydrolysis of p-nitrophenyl phosphate by the enzyme alkaline phosphatase. The progress of the reaction was monitored by measuring the absorbance due to p-nitrophenol, which is one of the products of the reaction. A plot of the rate of the reaction (with units of pmol mL s ) versus the volume, V, (in milliliters) of a serum calibration standard containing the enzyme yielded a straight line with the following equation... 

Enzymes, measured in clinical laboratories, for which kits are available include y-glutamyl transferase (GGT), alanine transferase [9000-86-6] (ALT), aldolase, a-amylase [9000-90-2] aspartate aminotransferase [9000-97-9], creatine kinase and its isoenzymes, galactose-l-phosphate uridyl transferase, Hpase, malate dehydrogenase [9001 -64-3], 5 -nucleotidase, phosphohexose isomerase, and pymvate kinase [9001-59-6]. One example is the measurement of aspartate aminotransferase, where the reaction is followed by monitoring the loss of NADH ... 

Operation and Control. Control of a chromium phosphate conversion coating bath requires monitoring chromium and aluminum concentrations, active fluoride level, and temperature. Coating weight is very sensitive to active, ie, uncomplexed, fluoride. An innovative electrochemical method using a siHcon electrode (25) is employed for measuring active fluoride. A special precaution in chromium phosphate bath operation is the... 

Sodium and chloride may be measured using ion-selective electrodes (see Electro analytical techniques). On-line monitors exist for these ions. Sihca and phosphate may be monitored colorimetricaHy. Iron is usually monitored by analysis of filters that have had a measured amount of water flow through them. Chloride, sulfate, phosphate, and other anions may be monitored by ion chromatography using chemical suppression. On-line ion chromatography is used at many nuclear power plants. 

Three types of methods for phosphate analyses have been studied with the aims of monitoring the distribution and circulation of orthophosphate and observing the chemical forms of phosphoms compounds occurring in the natural water environment. 

Fig. 6.3.11 Chromatography of an extract of the eye light organs of Symplecto-teuthis luminosa on a column of Superdex 200 Prep (1x27.5 cm) in 20 mM phosphate buffer, pH 6.0, containing 0.6 M NaCl, at 0°C (monitored at 280 nm). Each fraction (0.5 ml) is measured for the initial intensity of H202/catalase-triggered luminescence and the content of dehydrocoelenterazine measured as coelenterazine after NaBH4-reduction 1LU = 6 x 108 photons.

The reddish yellow solution is diluted with 4-5 volumes of cold water containing 5 mM 2-mercaptoethanol to reduce the conductivity to 0.7 m 2 1 or less, and applied to a column of DEAE-cellulose (coarse grade 5 x 15 cm) equilibrated with 2mM potassium phosphate, pH 8.0, containing 5mM 2-mercaptoethanol. The column is first washed with the cold equilibration buffer, then luciferin is eluted with a linear increase of potassium phosphate from 2 mM to 0.3 M, monitoring the effluent by fluorescence and the absorption at 390 nm. The rest of the purification method described below is adapted from the... 

A solution of 2.25 g (25 mmol) of D-glyccraldehyde in 300 mL of water is combined with a solution of 20 mmol of dihydroxyacetonc phosphate (DIIAP) in 200 mL of water freshly adjusted to pH 6.8. The mixture is incubated with 100 U of L-rhamnulose 1-phosphate aldolase at r.t. for 24 h with monitoring of conversion by TLC (2-propanol/sat. ammonia/water 6 4 2) and by enzymatic assay for DHAP55. 

Hydrolysis 10 mmol of the phosphate salt are dissolved by swirling with Dowex AG50W-X8 (H ) in 200 mL of water. After filtration, the pH is adjusted to 6.0, acid phosphatase (150 U EC 3.1.3.2) is added and the mixture is incubated at 25 CC until complete conversion, as monitored by TLC (48 h). The solution is desalted by ion exchange, concentrated in vacuo, and the residue is crystallized from ethanol to give colorless crystals of D-sorbosc yield 1.6g (89%). 

Monitor DO level and control pH at 6.7-7 by using 0.2 M phosphate buffer solution. 

Acid- and alkaline phosphatases act on a variety of mono- and multiple phosphate carrying low molecular mass molecules. In addition, they hydrolyze many, but not all, phosphoproteins. They are in use for decades to easily screen for diseases, however, somewhat unspe-cifially. For instance, acid phosphatase is used as biomarker for prostate cancer, and alkaline phosphatase to monitor bone (de-) mineralization and liver tumors. 

Apart from other control activities, such as the determination of phosphate, it is always necessary to closely monitor the FW sodium (Na) content. 

MgATP hydrolysis and electron transfer between the two proteins seems not to be direct and the order of reactions may depend on the precise conditions of the experiment at low temperature, electron transfer seems to be reversible (see Ref. 12) for a discussion). One innovation is incorporation of data in which the release of inorganic phosphate was monitored. With other MgATP hydrolyzing enzymes, this step is often the work step in which the energy released by MgATP hydrolysis is utilized. With nitrogenase this step takes place before the dissociation of the two proteins 106). 

Fig. 3. Comparison of transfection efficiencies obtained using PolyFect Reagent, a dendrimer-based transfection reagent, and a calcium phosphate-mediated procedure. COS-7 and HeLa cells were transfected in srx-weU plates with a /3-galactosidase expression plasmid using the appropriate protocol. For the calcium phosphate-mediated transfection, 6 pg of plasmid DNA was used and the medium was changed after 5 h incubation. Transfections were performed in triplicate, and transfection efficiency was measured by monitoring the /3-galactosidase activity of extracts obtained from the transfected cells. The amoimt of /3-galactosidase activity in the extracts correlates with the transfection efficiency. Cells were harvested 48 h post-trans-fection...

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