LNG and LBG are environmentally beneficial when used for long-distance road transport. Their use may be the most feasible alternative for a rapid conversion of heavy-duty transports towards a sustainable society and the goals of Agenda 2030. However, the roll-out of LNG and LBG as transport fuels requires reliable determination of their composition and physical properties in order to secure the quality and emission levels. As learned from current state-of-art, it is highly challenging to take a representative sample of LNG/LBG for subsequent analysis in a laboratory. This requires the proper vaporization of the fuel while avoiding partial vaporization and loss of fuel constituents and particles. The goal was to construct and test a sampler that would be compact and transportable for the simultaneous sampling of gas and solid particles at a commercial refueling station. Close to theoretical LNG pipeline temperature (-160 oC) was achieved in the measurement system in about 10 min, leading to minimal pre-vaporization and potential for fast, true and repeatable measurements. During the final test particles were quantified to 0.2 mg/Nm3 gas, with major number of particles being metal, metal oxide and silica. The gas composition measurements demonstrated a repeatability, defined as %RSD, of 0.3 % for main component methane (99.0 %), 2.0 % for ethane (615 ppm) and pooled standard deviation for all measurable components were below 1.0 %.