Soren Sorensen discovered pH in 1909 while studying the effect of ion concentration on protein analysis and testing the pH of beer he was brewing. pH measures the acidity or alkalinity of a solution on a scale of 0-14, where 7 is neutral. The pH of a substance is related to the concentration of hydrogen and hydroxide ions, with high hydrogen making it acidic and high hydroxide making it basic. pH can be measured using indicators, strips, or meters and is important in biology as it affects solubility, protein structure and function, and cell survival. Semen pH should be 7.2-7.8 according to WHO and abnormal pH can indicate infection or blockages and be associated

1. pH
Potential of hydrogen
or
Power of hydrogen

3. Soren Peter Lauritz Sorensen
• 9 JAN 1868
• Havrebjerg Denmark
• Biochemist
• Founder of pH (1909)
• He described the degree of acidity and
alkalinity
• He worked on the effect of ion concentration
in the analysis of protein
• He discovered it to test the pH of the beer he
was making

4. pH
• It is negative log of the H⁺ ion concentration
pH = -log [H⁺]
• It describe the acidity or alkalinity of solution
• It is measured through the pH scale
• pH value of substance can be related to the
concentration of presence of hydroxyl ion and
hydrogen ion

5. • If the H⁺ concentration is high, then material is
‘‘ACIDIC’’
• If the OH⁻ is high, the material is “BASIC”
• 7 is “NEUTRAL”

6. • pH can be measured through
 pH strips
 pH indicators
pH indicators are usually weak acid or
weak base that change colour at specific pH.
colorless phenolphthalein pink
 pH meter
Commonly used in chemistry lab
Ions sensitive electrodes are used to detect
the acidity and alkalinity

7. • pH paper
 pH papers are paper infused, or saturated, with pH
indicators or more frequently, a mixture of indicators
 The indicators infused into the paper are
predominantly weak acids
 Eg – litmus paper
 It turns red when the solution is acidic
 Blue – basic

8. Henderson-Hasselbach

9. Henderson-Hasselbach
Equation
• Consider a weak acid
HA ↔ H⁺ + A⁻
Ka = Dissociative constant
Ka = [H⁺] + [A⁻]
[HA]
Take a log on both sides
-log Ka = -log [H⁺] – log [A⁻] / [HA]
Apply –log(x) = p(x)

10. • pKa = pH – log [A⁻] / [HA]
• pH = pKa – log [A⁻] / [HA]
• pH = pKa + log [ BASE] / [ ACID]
• [A-] = molar concentration of a conjugate base
• [HA] = molar concentration of an
undissociated weak acid (M)
• pKa – constant

11. WHY pH IS IMPORTANT IN THE
BIOLOGY
• It affects the solubility of the substances
• Structure and function of the proteins
• Enzymes
• Many cells need particular pH for the survival

12. Semen and pH
• Semen pH is considered an essential part
during the semen analysis
• Abnormal pH may indicate the any infection or
blockage of seminal vesicles and prostatic
gland
• According to WHO manual pH should range
should be 7.2 – 7.8
• Acidic ejaculation may be associated with the
blockage of the seminal vesicle

13. • Semen pH vs. Motility
 More motile sperms was observed with the pH of
8 - 9
 According to WHO the pH range from 7.2-7.8,
were only 83% samples had optimum motility
 pH of 8-9 → 94% motility
• Semen pH vs. Morphology
Head defects
 pH 7-8 → 83% defects
 pH 8-9 → 86% defects

14. Mid piece
 pH 7.2 - 7.8, → 83%
 pH 8-9 → 88%
Tail defects
 pH 7.2-7.8, →84%
 pH 8-9 → 89%
• Semen pH vs. Viscosity
Samples tend to be more viscous in the
pH range of 8-9

15. • Semen pH and Azoospermia
When semen sample is low and
acidic pH we may consider it to be reflect
of “Congenital Bilateral Absence Of The
Vas Deferens “ and “Ejaculatory Ducts
Obstruction”

16. THANK
YOU