To establish a method for simultaneous determination of aluminum trioxide, silicon dioxide and magnesium oxide in montmorillonite and its preparations.
The method was optimized and established for simultaneous determination of aluminum (27Al), silicon (28Si), and magnesium (24Mg) in montmorillonite using rhadium (103Rh) as the internal standard, a dilute nitric acid hydrofluoric acid saturated boric acid solution with secondary microwave digestion and inductively coupled plasma mass spectrometry(ICP-MS). The method was compared and analyzed with the EDTA volumetric method for the determination of aluminum trioxide, the muffle ignition combustion method for the determination of silicon dioxide and the AAS method for the determination of magnesium oxide after melting samples of lithium metaborate in the USP.
The linear of aluminum (Al) and silicon (Si) were in the range of 25-300 ng·mL-1. The linear of magnesium (Mg) was in the range of 20-240 ng·mL-1, r≥0.999. The detection limits of Al, Si, and Mg were 0.49, 1.30, 0.71 ng·mL-1. The average recoveries were 99.7%-100.6%, 99.9%-101.2%, 99.8%-101.2%, and the average repeatability RSDs (n=6) were 0.3%-1.3%, 0.4%-1.2%, and 0.4%-1.0%. The contents of aluminum trioxide, silicon dioxide and magnesium oxide in montmorillonite, montmorillonite powder, and montmorillonite dispersion tablets were determined using the newly established method and the original standard method, and the measurement results were basically consistent. Eight common peaks were identified from fingerprints of 10 batches of samples. The RSD values of relative retention time of 8 common peaks of chromotograms of samples were all below 0.5% and the similarities were above 0.9. The contents of aluminum trioxide in montmorillonite were determined using the newly established method and the original standard method, which were 2.3% to 2.4%, 2.0% to 2.2%, 58.7% to 61.5%, 55.3% to 59.4%, and 15.9% to 20.6%, 14.6% to 19.4%, respectively. The results of the measurements were basically consistent for the determination of aluminum trioxide, silicon dioxide, and magnesium oxide content in montmorillonite raw materials and formulations.
The newly established content determination method uses a combination of secondary microwave digestion and ICP-MS technology to determine the content of aluminum oxide, silicon dioxide, and magnesium oxide in montmorillonite samples. It is simple, fast, sensitive, and accurate, and can be used.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |