Phosphate standard

The following data were obtained for a set of external phosphate standards. All absorbances have been corrected for a reagent blank. 

A particular mode of neurotoxicity was discovered for tricresyl phosphate that correlated with the presence of the o-cresyl isomer (or certain other specific aLkylphenyl isomers) in the triaryl phosphates. Many details of the chemistry and biochemistry of the toxic process have been elucidated (139,140,143—146). The use of low ortho-content cresols has become the accepted practice in industrial production of tricresyl phosphate. Standard in vivo tests, usually conducted with chickens sensitive to this mode of toxicity, have been developed for premarket testing of new or modified triaryl phosphates. As of 1992, the EPA called for extensive new toxicity and environmental data on this group of products (147). The Vederal e ster AoQ xm. ci. calling for this... 

Barium Sulphate To 1.0 g add a mixture of 3 ml 2M HNOs and 7 ml DW, heat on a water-bath for 5 minutes, filter, dilute the filtrate to 10 ml with DW, add 5 ml molybdovanadic reagent and allow to stand for 5 minutes. Any yellow colour produced is not more intense than that of a standard prepared simultaneously and in the same manner using 10 ml of phosphate standard solution (= 5 ppm P04) (50 ppm). 

Phosphate standards were prepared at 140, 200, and 260 ig/mL to have 70%, 100%, and 130% of the nominal value. Octanoic acid was added as an internal standard (Figure 18). 

Figure 1. Gas chromatogram ( Wt electron capture detection) of Iris (2,3-di-bromopropyl) phosphate standard...

Phosphate Evaporate 400 mg of sample to dryness on a steam bath. Dissolve the residue in 25 mL of approximately 0.5 N sulfuric acid, add 1 mL of ammonium molybdate solution [500 mg of (NH4)5Mo7024 4H20 in each 10 mL of water] and 1 mL of p-methylaminophenol sulfate TS, and allow it to stand for 2 h. Any blue color does not exceed that produced by 2.0 mL of Phosphate Standard Solution (20 pig PO4) (see Solutions and Indictors) in an equal volume of solution containing the quantities of the reagents used in the test. Residue on Evaporation Evaporate 25 g of sample to dryness in a tared porcelain or silica dish on a steam bath, and... 

Phosphate Standard Solution (10 pig P04 in 1 mL) Dissolve 143.3 mg of monobasic potassium phosphate (KH2P04) in water in a 100-mL volumetric flask, dilute to volume with water, and mix. Transfer 10.0 mL of this solution into a 1000-mL volumetric flask, dilute to volume with water, and mix. 

Transfer 20 /xl, 50 /xl, and 100 /xl of your extracted lipid sample in CHCI3 to three 4-ml glass vials with Teflon-lined screw caps. Transfer 0.30 ml of a 1 /xmol/ml phosphate standard solution to a fourth 4-ml glass vial. 

Prepare a series of phosphate standard solutions in 4-ml glass vials using the 0.3-ml sample of phosphate (1 /rrnol/ml) prepared on Day 2. 

Glucose-1-phosphate standard—Dissolve 100 mg glucose-1-phosphate dipotassium salt in 10 ml of distilled water store at 0 to 5°C. 

Phosphate standard solution—Dissolve 13.8 mg of NaH2P04 H20 in 100 ml of distilled water. 

Figure 5, Recorder signals obtained with the manifold shown in Figure 4. The blank solution is artificial seawate (7). The remaining solutions were natural seawater containing —0.9 /xM PO4 to which phosphate standard solution...

Primary phosphate standard 50 ppm of phosphorus Dry (AR) grade potassium... 

PiColorLock Phosphate Detection System (Innova Biosciences, Cambridge, UK) 100 pM phosphate standard. Gold reagent solution, accelerant solution, and stabilizer solution. Store at 4 °C or on ice during assay. 

Near the end of incubation, prepare serial dilutions of phosphate standard from the ColorLock reagent kit, in water. Dispense 6 pi of each concentration (100, 50, 25, 12.5, 6.25, 3.13, 1.56, 0 pM) in quadruplicate into the 1,536-well assay plate holding the assay mixture under incubation. For 0 pM prepare 16-32 replicate wells for sufficient sample size in subsequent data analysis. 

Fig. 1 Sample Phosphate standard calibration curve. ODess values are plotted against phosphate concentration in 6 pi assay volume, and the data fitted linearly. Slope is 0.017 0.0002, standard deviation of the background control is 0.0077, and the limit of detection (LOD) is 1.4 pM...

Optional) Perform phosphate standard calibration by repeating steps 6-9, Subheading 3.1 to ensure stability of the ColorLock reagents. 

Fast Red-naphthol phosphate standardized chromogen-substrate kit (e.g., Dako, code K0597). 

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