En sha allah iwill do on spectrophotometry and chromatography.

Need your support

Walid,

Do you usually drink quietly an expired yogurt? Some people do it depending on their intended purpose, does not it?! Think about the function of your reagent in your analytical test. Also you can test it previously and confirm. But, any result may not be submitted to publication, because expired reagents are prohibed in Analytical Chemistry.

Dear carlos your talk tell me that is ok but what the proplem in puplication if the test ok?

Dear dr walid

Precisely, if you have the powder with an expired date, so you should know the degree or percent of the degradation by apply reported and simple method for its determination, this is important. may be the pure powder have an expired date with certain percent you can consider in your determination (this in case the difficulty to get another qualified pure powder). If you work on the expired powder and construct the calibration curve for calculate the different concentrations of the tested sample from the dosage forms (in application part of your method), i think it will un accurate determinations, at this case you will consider also the present of the degradation obtained from the reported method you determined before (recovery value).

NOTE: All these trials away from the publication, you only display the qualified data without mention your trial and errors experiments.

Dear Mr. Walid, this is very relative. It's well know that L-ascorbic acid is unstable in solution. Its stability is a function of the pH. But, there is little information about unstability in solid form. We have a research about this problem with ascorbic acid tablets using thermal degradation and Arrhenius equation. The first results showed that L-ascorbic acid in solid form is very stable. We obtained a value of degradation lower than 0.01% for six years on shelf-life. I already analysed reagents with one hundred years on shelf-life and the degradation degree was minimum. Sodium chloride has a expired date of four years. But, sodium chloride is obtained from sea. Then, does the sea expired? Sodium chloride is very stable, but the manufacturer presents a legal expired date. This involves economical interest to allow the operation of the business gear. However, others reagents are very unstable even in solid form. For example, the enzymes. Therefore, is important that you check the purity of your reagent. If near "one hundred" percent, I think that you will not have problem to publicate your research if it has a new highlight.