1.1. Determination the pH of saliva.

A drop of saliva is applied to universal pH paper. Compare the color of the pH scale. Note the pH of saliva.

1.2. Detection of phosphates in saliva.

2 ml of saliva are deposited by 2 ml 10% of 3-chloroacetic acid solution. Filter it. To the filtrate add 4 ml of 5% ammonium molybdate solution in nitric acid. Heat it on a spirit lamp. Observe precipitation of the complex compound of ammonium phosphomolybdate of yellow color.

Experiment 2. Qualitative detection of inorganic components of urine.

2.1. Qualitative detection of chlorides in the urine.

Chlorine in the body is mainly in the ionized state. Osmotic pressure in blood plasma by 90% is due to the content of NaCl. Chloride ions play an important role in the formation of hydrochloric acid of gastric juice and in maintaining acid-base balance. Sodium chloride is excreted out of the body by the kidneys and sweat glands.

To 2 ml of urine add 2 drops of 5% nitric acid solution, 2-3 drops of 1% silver nitrate solution. Observe the white precipitate appearance.

2.2. Detection of calcium in the urine.

To 2 ml of urine add 4 drops of a saturated ammonium oxalate solution. Calcium oxalate is precipitated.

2.3. Detection of phosphates in the urine.

To 1 ml of urine add 2 drops of nitric acid; add 1 ml of ammonium molybdate solution and heat. There is a yellow precipitate.

Experiment 3. Deternination of inorganic phosphorus in blood serum with the reduction of the phosphomolybdic acid.

Phosphorus in the body is in the form of inorganic salts and organic compounds (phosphate esters of carbohydrates, phosphoproteins, nucleic acids, AMP, ADP, ATP, phospholipids, etc.). Blood plasma and serum contains predominantly such inorganic salts as monosubstituted and disubstituted phosphates. The content of inorganic phosphorus in blood serum in norm in adult is 2-4 mg% (0.65-1.3 mmol/l), the child is above (1.29-2.26 mmol/l). Hypophosphatemia is observed in rickets, parathyroid glands hyperfunction. Hyperphosphatemia is observed in an overdose of vitamin D, inadequate function of the parathyroid glands, renal failure.

To 1 ml of serum add 4 ml of distilled water, 5 ml of 10% trichloroacetic acid solution; leave it for 10 minutes. Precipitate of proteins is formed. Serum is centrifuged for 10 minutes. To 5 ml of supernatant add 1 ml of 5% ammonium molybdate solution, 0,2 ml of eikonogen solution and 1,8 ml of distilled water. The mixture is allowed to stand for 20 minutes at room temperature. Measure the absorbance at photoelectrocolorimeter against the control when a wavelength is 630-690 nm (red light filter).

Control is prepared simultaneously with the test sample. To 2.5 ml of trichloroacetic acid add 2.5 ml of water, 1 ml of ammonium molybdate, 0.2 ml of eikonogen, 1.8 ml of water. Leave for 20 minutes at room temperature.

Calculation is based on the calibration curve.

Plotting of the calibration curve. Prepare dilutions using the working standard solution, as indicated in Table 6.

Table 6