Determination of Chemical Oxygen Demand (COD)

 

Determination of Chemical Oxygen Demand (COD)

 

Chemical Oxygen Demand (COD):

 

Chemical oxygen demand (COD) is used to determine the quantity of pollution in waste water. The higher value of chemical oxygen demand indicates the higher organic pollution in water sample. Only chemically digest able matter can be determined by the COD test. COD determination takes less time than the Biological Oxygen Demand test. COD is recommended where the polluted water has toxicity and organic matter can’t be determined by biological oxygen demand.

Principle:

The organic matter, present in water sample is oxidized by potassium dichromate in the presence of sulfuric acid, silver sulfate and mercury sulfate to produce carbon dioxide (CO₂) and water (H₂O). The quantity of potassium dichromate used is calculated by the difference in volumes of ferrous ammonium sulfate consumed in blank and sample titrations. The quantity of potassium dichromate used in reaction is equivalent to the oxygen (O₂) used to oxidize the organic matter of water.

Preparation of Potassium dichromate (K₂Cr₂O₇) Solution:

Add 6.13 gm Potassium dichromate (previously dried at 105 °C for at least two hours) into 800 ml distilled water. Shake the flask well to dissolve the content and make up the solution to 1000 ml and mix well.

Preparation of Silver sulfate-Sulfuric acid Solution:

Dissolve 10 gm Silver sulfate (Ag₂SO₄) in 500 ml concentrated sulfuric acid and make up the solution to 1000 ml swirl the flask to mix well. Allow to stand the solution for 24 hours before use.

Preparation of Mercury sulfate Solution:

Dissolve carefully 0.1 gm of HgSO₄ in 5 ml of concentrated Sulfuric acid.

Preparation of Ferrous ammonium sulfate Solution (0.025 M):

Dissolve 9.8 g ferrous ammonium sulfate in a solution of 100 ml of distilled water and 20 ml concentrated Sulfuric acid. Cool the solution and make up the solution to 1000 ml with distilled water. Standardize the solution to determine the actual concentration to calculate the chemical oxygen demand.

Preparation of Ferroin Indicator:

Add 3.5 gm of Iron Sulfate heptahydrate and 7.5 gm of Phenanthroline monohydrate to 400 ml of distilled water. Mix well to dissolve and make up to 500 ml with distilled water.

Test for Chemical Oxygen Demand:

1. Take 10 ml of sample into a round bottom reflex flask.

2. Add some glass beads to prevent the solution from bumping in flask while heating.

3. Add 1 ml of Mercury sulfate (HgSO₄) solution to the flask and mix by swirling the flask.

4. Add 5 ml of Potassium dichromate (K₂Cr₂O₇) solution.

5. Now add slowly and carefully 15 ml Silver sulfate- Sulfuric acid solution.

6. Connect the reflex condenser and digestboil the content using hot plate for 2 hours.

7. After digestion cool the flask and rinse the condenser with 25 ml of distilled water collecting in the same flask.

8. Add 2-4 drops of ferroin indicator to the flask and titrate with 0.025 M ferrous ammonium sulfate solution to the end point.

9. Make the blank preparation in the same manner as sample using distilled water instead of sample.

Calculate the chemical oxygen demand by following formula:

COD = 8x1000xDFxMx(V_B - V_S) 

             Volume of sample (in ml)

Where,

DF – Dilution Factor (if applicable)

M – Molarity of standardized Ferrous Ammonium Sulfate solution

V_B – Volume consumed in titration with blank preparation

V_S – Volume consumed in titration with sample preparation

Example Calculation:

Volume of ferrous ammonium sulfate for Sample (V_S) = 23.8 ml

Volume of ferrous ammonium sulfate for Blank V_B) = 25.6 ml

Dilution Factor (DF) = 1 (sample used as it is)

 COD = 8x1000x1x0.025x(25.6-23.8)

                                 10

          = 8000x0.025x1.8

                       10

          = 360  =  36 mg/lit or ppm

              10

 

MUJIGA MAGESA, TOGETHER WITH PHARMACEUTICAL GUIDELINES WILL MAKE IT

 

 

 

MANAGEMENT OF DENGUE FEVER IN TANZANIA

 

 

Dengue fever is in fact a self-limited illness. We have no specific antiviral treatment currently available for dengue fever in Tanzania and in other parts of the world.

Supportive care with analgesics, fluid replacement( in Tanzania we prefer RL- RINGER LACTATE),  and bed rest is usually sufficient management of this dangerous viral infection. Acetaminophen( paracetamol) may be used to treat fever and relieve other symptoms.  Management of severe dengue requires careful attention to fluid management and proactive treatment of hemorrhage.

Aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids should be avoided..

Hospital pharmacist: Job description

Hospital pharmacists work in a hospital pharmacy service, primarily within the public sector. They are experts in the field of medicines and are not only responsible for the dispensing of prescriptions but also the purchase, manufacture and quality testing of all medicines used in a hospital. Pharmacists work closely with medical and nursing staff to ensure that patients receive the best treatment. They also provide help and advice to patients in all aspects of their medicines.
The role of a hospital pharmacist can extend outside the hospital with responsibility for medicines in health centres, nursing homes, hospices and general practitioners' (GP) surgeries.

Typical work activities

Tasks may include:

• checking prescriptions to ensure that there are no errors and that they are appropriate and safe for the individual patient;
• providing advice on the dosage of medicines and the most appropriate form of medication, for example, tablet, injection, ointment or inhaler;
• participating in ward rounds, taking patient drug histories and involvement in decision-making on appropriate treatments;
• discussing treatments with patients' relatives, community pharmacists and GPs;
• ensuring medicines are stored appropriately and securely;
• supervising the work of less experienced and less qualified staff;
• answering questions about medicines from within the hospital, other hospitals and the general public;
• keeping up to date with, and contributing to, research and development;
• writing guidelines for drug use within the hospital and implementing hospital regulations;
• providing information on expenditure on drugs;
• preparing and quality-checking sterile medications, for example, intravenous medications;
• setting up and supervising clinical trials.

More experienced pharmacists may be involved in teaching, both within the pharmacy department and in other areas of the hospital.

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Pyrogen and Its Determination Using Rabbits

Learn how to determine the pyrogens in parenteral preparations by injecting the sample in rabbits.

Introduction:

Pyrogen test is performed to check the presence or absence of pyrogens in all aqueous parenterals. Rabbits are used to perform the test because their body temperature increases when pyrogen is introduced by parenteral route.

For this test three healthy rabbits are selected each weighing at least 1.5 kg. No rabbit should be selected if:

1.  It has normal temperature greater than 49.8°C.

2.  It was used in positive test during last two weeks or negative test during last two days.

Method for Pyrogen Test:

The test is performed in an air conditioned room. The food and water is withheld to rabbit overnight. Clinical thermometer is inserted in the rectum of each rabbit to a depth of not less than 7.5 cm. Two readings of temperature of rabbit in normal conditions should be taken at the interval of half an hour before start the test and mean of the both should be calculated to determine the initial temperature.

The equipments, injectors and needles used in the test should be pyrogen free. These should be washed with WFI and then heated at 260°C for two hours. The injection is warmed to 38°C before inject to the rabbits. 0.5 to 1.0 ml per kg dose should be injected through the ear vein. Six reading of temperature are recorded at an interval of half an hour.

Test Results:

The response of each rabbit is detected by difference of initial temperature and the highest temperature recorded. The response of all three rabbits gives the sum of responses and can be concluded as:

i)  If the sum of responses dose not greater than 1.4°C and any of rabbit shows the response less than 0.6° C, the product passes the test.

ii)  I sum of responses is greater than 1.4 °C or any of rabbit shows the response 0.6 or greater, continue the test using 5 rabbits.

iii)  If test is done using 5 rabbits, than if sum of responses of all 5 rabbits is greater than 3.7°C and the individual response of not more than three rabbits is greater than 0.6°C, the product passes the test.

Also see: Pyrogens Testing in Pharmaceuticals

PREVALENCE OF MALARIA

WAIT TO READ MY RESEARCH ON PREVALENCE OF MALARIA CONDUCTED IN MWANZA, SEKOU TOURE HOSPITAL, this july

MY EDUCATIONAL BACKGROUND

Primary school:    MKIRIRA, MUSOMA


O'level:                  TABORA BOYS SECONDARY SCHOOL, TABORA


A'level:                   ILBORU HIGH SCHOOL, ARUSHA CITY


University:             St. John's University of Tanzania.


Degree course:       Bachelor of pharmacy

who is MUJIGA MAGESA

KNOW WHO IS MUJIGA MAGESA IN TANZANIA.





Mujiga is a current pharmacist who is to be registered so soon qualified as the holder of the bachelor degree of pharmacy from St. John's university of Tanzania 2013. Mujiga was born at MUSOMA district, MARA, by  April 26. My parents are ABIAH MWENURA ( MY MOTHER) and MUJIGA MWENDWA( my father).




this blog will make u aware of pharmacy related issues conducted here in tanzania and worldwide, also will notify u of necessary advertisements plus academic issues regarding to pharmacy practice in general.