Purity Testing of Silica Membrane

Membrane	Extractant	m/z	Ion	Compound	Source
Biocomma Silica Membrane	Pure Water	304	M+Na+	oleamide	Slip agent in polyethylene films
		97	HSO4-
			H2PO4-
	Methanol	360	M+Na+	erucamide	Slip agent in polyethylene films
Filters from Well-known brand	Pure Water	304	M+Na+	oleamide	Slip agent in polyethylene films
		97	HSO4-
			H2PO4-
	Methanol	360	M+Na+	erucamide	Slip agent in polyethylene films
		425	M+Na+	Unidentified contaminant
		701	M+Na+		from water and solvent filters

Remarks：
1. The table only records ions that match the “ESI Common Background Ions” reference table.
2. The results have deducted the ions present in the blank, but if a particular m/z ion significantly exceeds the blank, it is recorded.
Conclusion：
Proceed ultrasonic extraction in both water and methanol, mass spectrometry results showed the presence of precipitates in both Biocomma 
membrane and well-known brand filter. Compound identification was carried out through high-resolution mass spectrometry by full scanning and 
matching with the “ESI Common Background Ions” reference table. The primary precipitates were HSO4-, H2PO4-, and Na+, and these presence 
is attributed to the material being glass fiber in the membranes. No other substances were found to precipitate from either of the two membranes, 
confirming their purity.