A measurement of the41Ar content in the vial containing a liquid sample can be used to correct for variations in sample geometry due to changes in liquid sample volume. This technique makes use of the residual argon in the atmosphere when performing INAA of relatively short-lived radionuclides. The correction factor requires somea priori knowledge of the argon content of the solvent. Application of this correction technique requires the use of sample vials with consistent internal volumes. The need for correction is most evident with samples contained in vials of small cross section when using a vertically facing detector.