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FDA Issues Second Warning on Methanol Based Hand Sanitizers

27 Jul 2020

The U.S. Food and Drug Administration has placed methanol containing hand sanitizers on an import alert (1). These products do not list this ingredient and some are incorrectly labeled “FDA approved.” Currently, 87 hand sanitizers have been found to contain methanol (2). Methanol (methyl alcohol Cas# 67-56-1), known as wood alcohol, is commonly found in solvents, and windshield washer fluid (3). Ingestion of 10 mL can cause permanent blindness and 15 mL is considered a lethal dose (4,5). Transdermal methanol poisoning has been well documented and may result in optic nerve necrosis with permanent eye damage (6,7,8,9,10,11). Denatured alcohol is ethanol mixed with other alcohols and can contain 50% methanol. Other additives include isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate and methyl isobutyl ketone.

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Figure 1: Pro EZGC Chromatogram Model of a denatured alcohol sample illustrating the ability of this column / conditions to determine percent levels of methanol in samples, specifically hand sanitizers. Measured retention times are also indicated on the far-right column as a comparison to the predicted retention times.

This is the first part in a series addressing the different aspects of hand sanitizers. Our first goal is to determine a suitable column that can resolve methanol from water and ethanol. We accessed the safety data sheet (SDS) for our denatured alcohol sample and entered those compounds into our Pro EZGC Chromatogram Modeler (12). The program provides 5 different solutions / columns. Our column choice will be discussed in future blogs. Figure 1 is a model of the compounds with the expected retention time compared to the measured retention time using a mass spectrometer. While the model suggests resolution of the compounds, the sample has been diluted 50:1 in distilled water and the solvent peak width is not calculated by Pro EZGC.

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Figure 2: Denatured alcohol sample analyzed using a Rtx-VMS by GC/MS with an adjusted scan range to accommodate water and methanol detection. This method is suitable for the analysis of hand sanitizers containing methanol.

We followed USP 611 Method II (13) as a starting point. The MS scan range started at m/z 10 to detect water (m/z 18) and methanol (m/z 31). We also changed the GC program from the conditions suggested by Pro EZGC by adding a 3-minute hold time for better solvent focusing and slowed the initial ramp rate down to 3°C a minute. Future work will rely on our method translator to determine an equivalent solution using a Flame Ionization Detector (FID). Figure 2 is a total ion chromatogram (TIC) showing good resolution between water and methanol. Using a rinse solvent other than water could result in extraneous peaks, ghost peaks and carryover. The challenge with using 100% water as a rinse solvent is the potential that residue will build up in the syringe barrel. In this case we used a prewash with 100% water and three post washes with 90% water and 10% n-propanol. This method is suitable for measuring percent levels of methanol in samples. Our next blog will present gel and liquid hand sanitizers using this method.