PHOSPHATE BUFFER WITH MAGNESIUM CHLORIDE (MgCl 2 )

Cat. no. D690 Phosphate Buffer with MgCl 2 , Dilu-Lok II™ Vial, 90ml 50 vials/case
Cat. no. D699 Phosphate Buffer with MgCl 2 , Dilu-Lok II™ Vial, 99ml 50 vials/case
Cat. no. U193 Phosphate Buffer with MgCl 2 , 500ml Polycarbonate  Bottle, 500ml 10 bottles/box
Cat. no. U217 Phosphate Buffer with MgCl 2 , 1L Polycarbonate Bottle, 1000ml 10 bottles/box
Cat. no. U265 Phosphate Buffer with MgCl 2 , 500ml Polypropylene Bottle, 500ml 10 bottles/box

INTENDED USE

Hardy Diagnostics Phosphate Buffer with MgCl 2 is used to prepare dilutions of samples for examination of water, dairy products, foods and other materials.

This product is not intended to be used for the diagnosis of human disease.

SUMMARY

Phosphate Buffer with MgCl 2 is recommended by the American Public Health Association (APHA), for the recovery of injured microorganisms from dairy and food samples. Dilu-Lok II™ Phosphate Buffer with MgCl 2 is prepared as specified in the Standard Methods for the Examination of Dairy Products and Standard Methods for the Examination of Water and Wastewater . Potassium phosphate is added the formula to maintain the pH and the addition of magnesium chloride aids in the recovery of organisms that may be metabolically injured.

FORMULA

Ingredients per liter of deionized water:*

Monopotassium Phosphate 42.5mg
Magnesium Chloride 190.0mg

Final pH 7.2 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Storage: Upon receipt store at 2-30ºC. away from direct light. Media should not be used if there are any signs of deterioration (shrinking, cracking, or discoloration), contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat and freezing.

PRECAUTIONS

PROCEDURE

Consult listed references for information on specimen collection and specific standard methods. (1-4)

General Dilution Guidelines:

1:10 Serial Dilutions:
1. Using a sterile pipet, aliquot 10ml of test suspension to 90ml of the Dilu-Lok II™ diluent. Mix thoroughly. This yields a 1:10 dilution.

2. Use a second sterile pipet to aliquot 10ml of the 1:10 dilution prepared in step 1 into a second 90ml filled Dilu-Lok II™ diluent. Mix thoroughly. This yields a 1:100 dilution.

3. Continue aliquoting 10ml of subsequent dilutions into 90ml filled Dilu-Lok II™ diluents until the desired concentration of test sample is obtained. Each succeeding dilution increases by a factor of 10. A separate sterile pipet should be used with each dilution.

1:100 Serial Dilutions:
1a. Using a sterile pipet, aliquot 1ml of test suspension to 99ml of the Dilu-Lok II™ diluent. Mix thoroughly. This yields a 1:100 dilution.

2a. Use a second sterile pipet to aliquot 1ml of the 1:100 dilution prepared in step 1a into a second 99ml filled Dilu-Lok II™ diluent. Mix thoroughly. This yields a 1:10,000 dilution.

3a. Continue aliquoting 1ml of subsequent dilutions into 99ml filled Dilu-Lok II™ diluents until the desired concentration of test sample is obtained. Each succeeding dilution increases by a factor of 100. A separate sterile pipet should be used with each dilution.

INTERPRETATION OF RESULTS

See listed references for interpretation of growth. (2,5,6)

LIMITATIONS

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.

QUALITY CONTROL

Hardy Diagnostics tests Phosphate Buffer with MgCl 2 for sterility, pH, and fill volume.

It can be difficult to accurately measure the pH of high purity water products as these products have low hydrogen ion activity. When troubleshooting potential pH problems associated with diluents ensure that the electrode is rinsed thoroughly before immersion in the water sample, that the pH is measured immediately after placing the electrode deep in the sample, and that the reference electrode provides minimal junction potential (0.1KCl provides greater stability and compatibility). Hardy Diagnostics recommends that pH measurements of Dilu-Lok II™ Phosphate Buffer with MgCl 2 be taken with electrodes specifically designed for low ionic strength water dilutions. (1,8)

USER QUALITY CONTROL

PHYSICAL APPEARANCE

Phosphate Buffer with MgCl 2 should appear clear and colorless, with no precipitate or debris.

REFERENCES

1. American Public Health Association. Standard Methods for the Examination of Water and Wastewater, APHA, Washington, D.C.

2. U.S. Food and Drug Administration. Bacteriological Analytical Manual. Arlington, VA. http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm2006949.htm

3. Association of Official Analytical Chemists. Official Methods of Analysis , AOAC, Washington, D.C.

4. American Public Health Association. Standard Methods for the Examination of Dairy Products, APHA, Washington, D.C.

5. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, Washington, D.C.


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