Standard method for identifying species in solid mixtures

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Discussion Overview

The discussion focuses on methods for identifying and quantifying species in solid mixtures, specifically in the context of precipitating hydroxyapatite (HAP) from solutions of K2HPO4 and CaCl2. Participants explore the challenges of qualitative and quantitative analysis of complex mixtures.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants emphasize the need for qualitative identification before quantification, suggesting that understanding the sample's composition is crucial.
  • There is mention of various analytical techniques that could be employed, including spectroscopic methods (FTIR, NMR, MS, UV-Vis) and metals analysis techniques (Flame AA, ICP, XRF, PIXE, SEM).
  • One participant notes the importance of gathering extensive data on individual components, such as melting points, boiling points, solubilities, and densities.
  • A later reply clarifies the specific context of the inquiry, indicating that the mixture involves precipitating hydroxyapatite and expressing a desire to quantify the amount of HAP in the final product.
  • There is an acknowledgment that other calcium phosphate crystals may precipitate alongside HAP, complicating the quantification process.

Areas of Agreement / Disagreement

Participants generally agree on the complexity of identifying and quantifying species in solid mixtures, but multiple competing views remain regarding the specific methods and challenges involved in the analysis.

Contextual Notes

Participants highlight the need for a comprehensive understanding of the sample's characteristics and the limitations of qualitative versus quantitative analysis in complex mixtures.

Dong Aleta
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I want to know of any standard method for identifying (and possibly quantifying) the species contained in a solid mixture sample. Thanks in advance!
 
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Cake mixes? Or, actual/real mixtures?
 
Dong Aleta said:
I want to know of any standard method for identifying (and possibly quantifying) the species contained in a solid mixture sample. Thanks in advance!

You are SOL. Unless you know a whole lot about your sample. Qualitative identification comes first, then quantitation. Is your sample organic or inorganic or both? What functional groups does it contain. You need a slew of data. You need melt points, boiling points (if applicable). You need solubilities. You need densities. You need spectroscopic data, FTIR, NMR, MS, UV-Vis. You might some form of metals analysis, Flame AA, ICP, XRF, PIXE, SEM.

You need to separate individual components and gather all the data on the individual compounds. Reverse engineering complex mixtures is quite a challenge.
 
Kevin McHugh said:
You are SOL. Unless you know a whole lot about your sample. Qualitative identification comes first, then quantitation. Is your sample organic or inorganic or both? What functional groups does it contain. You need a slew of data. You need melt points, boiling points (if applicable). You need solubilities. You need densities. You need spectroscopic data, FTIR, NMR, MS, UV-Vis. You might some form of metals analysis, Flame AA, ICP, XRF, PIXE, SEM.

You need to separate individual components and gather all the data on the individual compounds. Reverse engineering complex mixtures is quite a challenge.
I apologize for not specifying. I want to precipitate hydroxyapatite (HAP) by mixing two solutions of K2HPO4 and CaCl2 at initial pH 9~9.5. I did some literature review and found out that apparently, we know of other calcium phosphate crystals can precipitate other than HAP. But I want to be able to quantify (if possible) how much HAP was precipitated in the resulting precipitate (after filtration and drying).
 
Bystander said:
Cake mixes? Or, actual/real mixtures?
Actually, it's a precipitate after mixing solutions of K2HPO4 and CaCl2, after filtration and drying.
 

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