A standard solution for inverse gas chromatography and/or surface energy analysis comprising a series of three or more compounds of increasing carbon chain length of general formula (I): R-X wherein: for the three or more compounds R is a series of alkyl, a series of alkenyl or a series of alkynyl groups of increasing carbon chain length; and for all three or more compounds X is H, OH, CO 2 H, C(O)H, C(O)CH 3 , NH 2 , SH or halogen; and the relationship between carbon chain length and volume of the compounds of increasing carbon chain length of general formula (I) is determined by the following formula: Relative Volume x = MW x × P y 0 × Area y × Density y MW y × P x 0 × Area x × Density x ± 20 % wherein: Relative Volume x is the volume of a specific compound x in the series relative to the volume of compound y that has the shortest carbon chain length in the series; MW x is the molecular weight of the specific compound x; P 0 x is the vapour pressure of the pure specific compound x at a given incubation temperature; Area x is the cross-sectional area of the compound x; Density x is the density of x. MW y is the molecular weight of the compound y; P 0 y is the vapour pressure of compound y at the given incubation temperature; Area y is the cross-sectional area of compound y; Density y is the density of compound y; and the parameter ± 20% means that Relative Volume x is a range of ± 20% of the value obtained from the calculation. for the three or more compounds R is a series of alkyl, a series of alkenyl or a series of alkynyl groups of increasing carbon chain length; and for all three or more compounds X is H, OH, CO 2 H, C(O)H, C(O)CH 3 , NH 2 , SH or halogen; and the relationship between carbon chain length and volume of the compounds of increasing carbon chain length of general formula (I) is determined by the following formula: Relative Volume x = MW x × P y 0 × Area y × Density y MW y × P x 0 × Area x × Density x ± 20 % wherein: Relative Volume x is the volume of a specific compound x in the series relative to the volume of compound y that has the shortest carbon chain length in the series; MW x is the molecular weight of the specific compound x; P 0 x is the vapour pressure of the pure specific compound x at a given incubation temperature; Area x is the cross-sectional area of the compound x; Density x is the density of x. MW y is the molecular weight of the compound y; P 0 y is the vapour pressure of compound y at the given incubation temperature; Area y is the cross-sectional area of compound y; Density y is the density of compound y; and the parameter ± 20% means that Relative Volume x is a range of ± 20% of the value obtained from the calculation. Relative Volume x is the volume of a specific compound x in the series relative to the volume of compound y that has the shortest carbon chain length in the series; MW x is the molecular weight of the specific compound x; P 0 x is the vapour pressure of the pure specific compound x at a given incubation temperature; Area x is the cross-sectional area of the compound x; Density x is the density of x. MW y is the molecular weight of the compound y; P 0 y is the vapour pressure of compound y at the given incubation temperature; Area y is the cross-sectional area of compound y; Density y is the density of compound y; and the parameter ± 20% means that Relative Volume x is a range of ± 20% of the value obtained from the calculation. <EOS>