The document discusses the concepts of sampling, including types of samples (solid, liquid, gas) and the importance of homogeneity to ensure accurate analysis. It outlines the process of reducing a gross sample to a laboratory sample and lists different methods of analysis based on sample size. Key considerations for effective sampling and sample preservation are emphasized to maintain the integrity of the samples.

1. Sample and
Sampling

2. Sample
Small representative portion of bulk material
Types of Sample
• Solid
• Liquid
• Gas

3. Solid Sample
• Grind the material
• decrease its particles size
• Then mix it to ensure its
homogeneity
Storage
• Store properly because
absorption and adsorption
change the Conc.

4. Liquid Sample
• It should be in one phase
Storage
• Store properly because liquid could be evaporate
• And it may change the Conc.

5. Gaseous Sample
• Gases are generally more
homogenous than liquid and solid
Storage
• Sample container, may be kept in
second sealed container, to ensure
the conc. Of gas should be intact

6. • Gross Sample consistsof severalportionof
the material to be tested
• Laboratory Sample consistsof a small
portion of grosssample made homogenous
• Analysis Sample isthatwhich is
actually analyzed
Types of Samples
Gross Sample
Laboratory Sample
Analysis Sample
(Few g to Kg)
Bulk of Material
(Few g)
(a drop, few mg, few mL)

8. Classification of Analysis on the Basis of Size of
Sample
• Macro Analysis
Large quantities of the sample are used
Measurement: 0.1g or more
• Semi-micro Analysis
Lower quantity than macro analysis
Measurement: 0.01-0.1g
• Micro Analysis
Small in quantity
Measurement: 0.001-0.01g
• Ultra-micro Analysis
More smaller in quantity
Measurement: less than 0.001g

9. Sampling
is the process of by which we collect a representative portion or small amount of
material that accurately represent the bulk of the material being analyzed
(We can not analyze the whole thing!)
Important Consideration in Sampling
• It should be a Homegenous for absolute accuracy
• Sample must be consist of the entire body of material
• Size of sample (for liquid in mL) (for solid in mg or gm)
• Select independent method of sampling to minimize the possibility of errors
• Homogenous Sample: has the same proportions of its components throughout a
given sample
• Heterogeneous Sample: are ones in which their constituents do not mix uniformly

10. Sample Preservation
Sample Preparation
Analysis
Sampling
Collect sample
Reduce Gross sample to Lab sample
Analysis Sample
(Gross Sample)
(Laboratory Sample)
(a drop, few mg, few mL)
Steps involved in a
measurement process
Identify Popu
Steps involved in
Sampling process
(Bulk)