Pharmaceutical analysis unit - 1st
✯Unit - 1st✯
Method of expressing concerntration;
1. Normality (N) ;
• Normality is described as the number of gram or moles equivalent of solute present in one ltr. Of a solution. When we say equivalent, it is the number of moles of reactive units in a compound.
Where is,
N= Normality
WB = weight of solute
Gewb = gram equivalent weight of solute.
Vs = volume of solution
2. Molarity;
• Molarity is the amount of a substance in a certain volume of solution, molarity is defined as the moles of a solute per ltr. Of a solution.
Gmmb = gram molecules mass of solute
3. Molality;
•. Molality, or molal concerntration, is the amount of a substance dissolved in a certain mass of solvent. It is defined as the moles of a solute per kg of a solvent.
Wa = weight of solute
4. Parts per million ( p.p.m.);
5. % w/w
6. % w/v
7. % v/v
8. % v/w
◍ Standard solution;
• That solution whose concerntration is a known concentration is called standard solution.
It's two type -;
1. Primary solution;
• when a specific quantity of substance is mind in specified quantity of substance is mind in specified procedure is called primary standard solution. This standard solution should be 100% pure.
2. Secondary solution;
,• These solution which are made with the help of primary standard that is called secondary standard solution.
The concentration and purify should be some as the primary standard solution.
Gram equivalent weight;
• The ratio of weight of substance to its equivalent weight is called gram equivalent weight.
Gram equivalent weight= weight of substance / equivalent weight
Equivalent weight= molecular weight/ vallency factor
Accuracy;
• The accuracy is defined as the clasenes of exact value or most probable value.
Precision;
• precision is defined as the concardance of source of agreement of the some quantity or precision is most time repeated value.
Errors;
,• It is observed that the numerical data optioned in quantitative analysis differ to greater of lessar extent .
" The difference between value and observe value is called errors".
Classification of errors;
• On the bases of determination of magnitude errors can be classified into following types.
1. Systematic errors;
a. Personal systematic errors.
b. Operational systematic errors.
c. Instrumental systematic errors.
d. Methodic systematic errors.
2. Random errors
3. Errors measurement
4. Grass errors
1. Systematic errors ( determinate errors);
• Systematic errors is always remain constant and it can be determine .
It's following types —
a. Personal systematic errors;
• Inability judging colour change during end point.
• The estingation value v/w scale division in burette.
• Inability to detected the end point to determination.
• Errors In calculation in weighing.
b. Operational systematic errors;
• Weighing of moisturised drugs before drying.
• In clean washing.
• In correct draining of solution.
c. Instrumental errors;
• Disturbance in weighing balance.
• In correctly graduated.
• In correct technic involve in solution transfer.
d. Methodic systematic errors;
• Difference between the observed the end point and actual end point .
• The indicator used in the reaction is wrong.
• The pH meter that has been wrongly standardise.
2. Random errors;
• Random errors are beyond the observation of observe and it is accidentally nature this type of errors can not be determine so it is called indeterminate errors.
3. Errors of measurement;
• This errors arise in every measurement which includes any analytical determination no matter have carefully it is perform.
Example-
• errors in weighing deu to insensitivity of balance.
• placing the weight of the edge of fan.
• using non calibrated weight.
4. Grass errors;
• Wrong formula fond method conclusion this type of errors is appear when to use wrong formula and method for calculation and due to unsultable of method of storage.
Minimization of systematic errors;
• Errors may effect the actual result of analysis and use reduce the errors upto (0) zero percent but use can minimise the errors by following.
1. Calibration of apparatus
2. Analysis of standard sample
3. Running blank determination
4. Use of independence analysis reagents.
5. Indentity the colour sharply during end point.
6. Use correct method and formula.
7. Properly wash and dry the apparatus before use.
8. Use suitable indicator for each titration.
9. Appoint trained & educated staff.
Significant figure;
•A significant figure is a digit having some practical meaning it is a figure or digit donate the amount of quantity in the place in which it stand .
Rule-;
1. Non-zero number are always significant.
Example- 9523= 4 , 23454= 5
2. In v/ w zero's are always significant.
Example- 101= 3 , 3002= 4 , 35.67= 4
3. Leading zero are never significant.
Example- 01= 1 , 00205= 3 , 0.0025= 2
4. Trailing zero are some time significant.
Example- 580 = 2 , 2700= 2 , 2770000= 3
5. The decternal quantity is always written into digit after decimal it the third digit after decimal more than ( five than second digit )
Example- 0.2087= 0.21, 9.006= 9.006, 8.7564= 8.75
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