Analysis of hydroxylamine hydrochloride content
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Hello everyone. I have a question for you: when using the redox method to analyze the content of hydroxylamine hydrochloride, why has its concentration exceeded 100 in the past 3 months? Additionally, the reproducibility of results obtained from parallel tests is poor. I have been trying to figure out the reasons behind this, and in order to identify any factors that may be causing this issue, I would like to discuss it with everyone in order to find a solution. (Ps: Last year, when analyzing the content of hydroxylamine hydrochloride, the values remained fairly stable; there was no occurrence of levels exceeding 100, and the consistency among the replicate samples was good.) ) The experimental method used now is the same as before, and the potassium permanganate solution has also just been prepared. Thank you all! ! ! !
When using hydroxylamine hydrochloride for redox titration to determine the hydroxylamine content, it is necessary to strictly control the acidity during the titration process. If the acidity is too high, potassium permanganate will oxidize chloride ions, resulting in an overestimated value of the hydroxylamine content. Sample acidity adjustment should be carried out strictly in accordance with the standard methods; the titration speed should not be too fast, and it is best to use a potential indicator for detecting the endpoint, as visual observation may sometimes lead to inaccuracies.
Hello, teacher. First of all, thank you for your previous replies. During the experiments earlier, in order to prevent the hydrolysis of ammonium ferric sulfate, I would often add sulfuric acid when preparing it (about 10 ml of concentrated sulfuric acid per 200 ml of solution). Today, following your advice, I did not add sulfuric acid when preparing ammonium ferric sulfate. The experimental results showed that the purity of hydroxylamine hydrochloride in this case was around 99.75%, which is consistent with the results from previous experiments. . . But at the same time, new problems have arisen: when analyzing hydroxylamine hydrochloride before, some sulfuric acid was also added during the preparation of ammonium ferric sulfate. However, the purity of hydroxylamine hydrochloride had always been around 99.6%, with no cases of it exceeding 100%. I have been thinking about this issue, and I hope the teacher can offer some suggestions and discuss it with me. Thank you, teacher! !
It mainly depends on the process used to produce hydroxylamine hydrochloride; sometimes sulfuric acid is involved in the reaction, which affects the analysis of the hydroxylamine content.