Page 6 - Application Notebook - Hand Sanitizer Analysis

Application Gas Chromatography

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Alcohol Determination of Sanitizer Gel
in accordance with USP<611>
No. G333

United States Pharmacopeia (USP) General Chapters  Analysis Conditions
<611> ALCOHOL DETERMINATION stipulates two Using the gas chromatograph Nexis™ GC-2030,
analytical methods for quantitating ethanol: one with ethanol in the standard solution and the sample
distillation and the other by gas chromatography. The solution were quantitated according to
latter (i.e. USP <611> Method II) further gives an USP<611>ALCOHOL DETERMINATION Method IIb. The
option of either using a packed column (Method II a) instrument configuration and analysis conditions for
or a capillary column (Method II b).
the this experiment are listed below in Table 1.
This article introduces a quantitative analysis of
ethanol in alcohol-based sanitizer gel according to Table 1 Instrument Configuration and Analysis Conditions
USP <611> Method II b.
Model : Nexis GC-2030 + AOC-20i Plus
N. Iwasa, T. Wada Detector : FID-2030 flame ionization detector
Column : SH-Rtx™-624 (30 m×0.53 mm I.D., d.f.= 3 µm)
Column Temperature : 50 °C (5 min) – 10 °C/min – 200 °C (4 min)
Total 24 mins
 Preparation of Standard Solution and Sample Injection Temperature : 210 °C
Solution Injection Mode : Split
5 mL each of 2 %(v/v) ethanol *1 and 2 %(v/v) Split Ratio : 1: 5
: Linear velocity (He)
Carrier Gas Controller
acetonitrile *1 (internal standard), both in water, were Linear Velocity : 34 cm/sec
pipetted into a 25 mL volumetric flask, made up to Detector Temperature : 280 °C
FID H 2 Flow Rate : 32 mL/min
volume with water and vortex to prepare a 0.4 %(v/v) FID Make up Flow Rate : 24 mL/min (He)
standard solution. FID Air Flow Rate : 200 mL/min
Injection Volume : 0.2 µL
As a sample solution, a commercially available sanitizer Syringe : Elastic Syringe, AOC (P/N: 221-49548) *2
gel (ca. 80 %(v/v)) was first diluted with water to ca. 2
%(v/v) ethanol. To further bring down the concentration *2 When samples in aqueous solution are analyzed with a standard
to ca. 0.4 %(v/v), 5 mL of each of the prepared ca. 2 syringe for AOC-20i Plus, the plunger motion may become dull
%(v/v) sample and 2 %(v/v) acetonitrile were aliquoted during analysis, which affects repeatability. Using an elastic
syringe for AOC (P/N: 221-49548) equipped with a plunger made
into 25 mL volumetric flask and mixture was make up to
of titanium enables stable sample introduction.
volume with water.
*1 USP<611> specifies the use of USP Alcohol Determination-Alcohol In this analysis, a glass insert was specifically
RS (2 %(v/v) ethanol) and USP Alcohol Determination-Acetonitrile RS configured as shown in Fig.2 to meet the requirements
(2 %(v/v) acetonitrile) to prepare the standard solution. for the system suitability test(SST) in USP<611>. 20 mg
of deactivated glass wool was packed into a split glass
<Standard solution> <Sample solution>
insert at a position 20 mm from the top. Increasing the
Sample: ca. 80 %(v/v) ethanol amount of wool compared to the default amount of 10
mg and placing the wool slightly (i.e. 2 mm) above the
Dilute the sample
40-fold default position (i.e. 22 mm from the top) improved
reproducibility.
2 %(v/v) ethanol Sample: ca. 2 %(v/v) ethanol
＋ ＋
IS: 2 %(v/v) acetonitrile IS: 2 %(v/v) acetonitrile
20 mm
Dilute each sample Dilute each
5-fold sample 5-fold

95 mm
20 mg of glass wool
(P/N: 221-48600)

25 mL 25 mL
Insert for split injection
(P/N: 221-41444-84)
0.4 %(v/v) standard solution ca. 0.4 %(v/v) sample solution
Fig. 2 Position and Quantity of Wool in the Insert
Fig. 1 Sample Preparation Method