Application Note: Sulfated Ash with prepASH® 340 Series
Ashing test procedures performed on pharmaceutical, polymer, and food samples frequently involve the use of H2SO4 resulting in sulfated ash.
Hot sulfuric acid vapour released during these procedures is both hazardous to analysts and corrosive to equipment. In addition to these complications, sulfate ashing procedures are typically labour-intensive and time consuming, requiring manual fuming of acid from crucibles. Hot sulfuric acid vapour released during these procedures is both hazardous to analysts and corrosive to equipment. In addition to these complications, sulfate ashing procedures are typically labour-intensive and time consuming, requiring manual faming of acid from crucibles.
The chemical background
The chemical background of doing sulfated ash instead of “crude” ash is to get the ash in a defined form:
When phosphorus is absent, barium, calcium, magnesium, sodium, and potassium are converted to their sulfates. Tin and zinc are converted to their oxides. Some minerals are essential to a healthy diet (e.g., calcium, phosphorous, potassium and sodium) whereas others can be toxic (e.g., lead, mercury, cadmium and aluminium).
Sulfated ash is the standard method of ashing in American and European pharmacopoeia.
The pharmaceutical industry and their suppliers therefore have to do sulfated ash.
- dry plants
Working Steps of Moisture and Ash Determination
|Standard method with oven
|Heating out crucibles for constant weight before
|Possibility for pre-define a “heating out program”
|Measuring tare of crucible one by one
|Weighing + documentation of each crucible
|AUTOMATICAL + entering the sample name/ID
|Samples in drying oven + START
|Removing samples from oven + cool down
|Back weighing samples, calculation (moisture)
|Pre-ashing with rapid incinerator or hot plate
|Samples in muffle furnace
|Removing samples + cooling down in exicator
|Back weighing for stable results (repeat?)
|Calculation and documentation (ash)
Addition of sulfuric acid
Take the carousel of the prepASH.
Easy Pipetting of sulfuric acid in cold crucibles under the hood.
Pre-ashing and ashing
Safety: no manual fuming of toxic and irritating sulfuric acid.
Automatic fuming of sulfuric acid within closed prepASH condensing and washing of the gases in the attached scrubber.
Precisa’s Ash Analyser
The prepASH® TGA Thermogravimetric Analyzer by Precisa combines high performance, ease of operation, precision and integrity of measurement to maximise time and accuracy in thermogravimetric analysis, as well as traceability in all measurements.
To find out more, contact our sales team today who will be happy to assist.
Download the full application note: Sulfated Ash with prepASH® 340 Series.