Лабораторный практикум по экологии

Essence calorimetric method to determine the pH.Law of Lamberta- Beera.

Measure methods of рН.

There are three methods for measuring pH; a probe and meter, litmus paper, and a field kit. The most accurate and reliable method is the probe and meter. This method is no less convenient than the other methods, but requires a more expensive piece of equipment.

Probe and Meter

Calibrate the probe and meter according to the manufacturer’s directions. Use of two buffers (pH 7 and 10) for calibration is recommended.

Sample water can be collected in any glass or plastic container. Collect enough sample water so that you can submerge the tip of the probe. Rinse the probe with sample water before placing it in the sample.

Place the probe in the sample and wait for the meter to equilibrate. If the meter needs to be manually adjusted to correct for temperature – you’ll know it does if it has an extra temperature knob – adjust it to the temperature of the sample before allowing it to equilibrate. The meter will have come to equilibrium when the signal becomes steady. If it is taking a long time to equilibrate, you may try gently stirring the probe. However, do not agitate the sample since this may cause changes in the pH.

Method of definition of concentration of the solutions by intensity of their colors is called colorimetric definition. Of the concentration. On the base of this method is law of Lambert which states: If two solutions absorb the light equally the product of concentration of the solution and thickness of the layer is a constant value.

9. Calorimetric method: a) method equalization; b) method of color scale.

So, if two solution the same substances have the same color by the same thickness of color then their concentrations are identical. There are two colorimetric analysis:

1) Method of equalization

2) Method of color scale

a) Orientation definition of the PH

b) Make a table of Buffer solution and choose the solution having PH

c) Choose the indicator that changes the color within the limits of PH which found before

d) Make the color scale from the Buffer solution

e) Use the same indicator for the investigated solution and for Buffer solutions in the scale.

для студентов очной, очно-заочной и заочной форм обучения

инженерно-технических специальностей

Уфа 2008

Лабораторный практикум предназначен для студентов высших учебных заведений инженерно-технических специальностей, изучающих курс экологии. Включенные в практикум химические методы анализа широко используются в настоящее время в центрах Санэпиднадзора России, а тематика лабораторных работ максимально приближена к наиболее актуальным проблемам современности.

В каждой лабораторной работе коротко изложены проблемы, связанные с состоянием окружающей среды, и пути их решения. Описаны доступные методы исследования некоторых объектов окружающей среды.

Составители:	Михольская И.Н., доц., канд. биол. наук Фомина В.В., ассистент Хайбуллин А.А., доц., канд. техн. наук
Рецензенты:	Баширов Р.Ф., нач. отдела технико-технологического планирования департамента перспективного развития и инвестиций ОАО «Салаватнефтеоргсинтез, канд. техн. наук Худайдатов Р.Г., доц., канд. техн. наук

© Уфимский государственный нефтяной технический университет, 2008

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