A fitting assembly for use in an analytical system, the fitting assembly being for securing a tube and comprising: - a fitting component for receiving an end of the tube, said fitting component having a fitting component body comprising: o inner lateral walls defining a cavity extending axially through the body, the cavity having a tube-receiving section open at a first end for receiving the end of the tube therein; and o a radial annular flange at a second end of the cavity for abutting a rim of the end of the tube; and - a front ferrule and a rear ferrule, the front and rear ferrules being ring-shaped with a central bore sized to receive the tube there-through; the fitting assembly being characterized in that it comprises a nut for securing the tube to the fitting component, the nut engaging with the fitting component and biasing the front and rear ferrules to deform the tube, the nut having a nut body with first and second ends, the nut body comprising: ∘ an inner sidewall and an outer sidewall extending between the first and second ends, the inner sidewall defining a bore opening at the first and second ends, said bore being sized to receive the tube therethrough; ∘ a fitting interface at the first end for engaging with the fitting component; ∘ a tube interface at the second end for fitting around the tube; and ∘ a channel extending through the nut body, between the inner sidewall and the outer sidewall, said channel providing a path for fluid between the bore and an exterior of the nut body, said channel being provided with a sealing element; wherein, when the nut secures the tube to the fitting component, a leak chamber is defined in a space between the tube, the fitting component and the inner sidewall of the nut body, the leak chamber being in fluid communication with the exterior of the nut body via the channel in the nut body, further wherein the sealing element seals the channel to contain leaks and allow pressure to build up in the leak chamber. - a fitting component for receiving an end of the tube, said fitting component having a fitting component body comprising: o inner lateral walls defining a cavity extending axially through the body, the cavity having a tube-receiving section open at a first end for receiving the end of the tube therein; and o a radial annular flange at a second end of the cavity for abutting a rim of the end of the tube; and o inner lateral walls defining a cavity extending axially through the body, the cavity having a tube-receiving section open at a first end for receiving the end of the tube therein; and o a radial annular flange at a second end of the cavity for abutting a rim of the end of the tube; and - a front ferrule and a rear ferrule, the front and rear ferrules being ring-shaped with a central bore sized to receive the tube there-through; the fitting assembly being characterized in that it comprises a nut for securing the tube to the fitting component, the nut engaging with the fitting component and biasing the front and rear ferrules to deform the tube, the nut having a nut body with first and second ends, the nut body comprising: ∘ an inner sidewall and an outer sidewall extending between the first and second ends, the inner sidewall defining a bore opening at the first and second ends, said bore being sized to receive the tube therethrough; ∘ a fitting interface at the first end for engaging with the fitting component; ∘ a tube interface at the second end for fitting around the tube; and ∘ a channel extending through the nut body, between the inner sidewall and the outer sidewall, said channel providing a path for fluid between the bore and an exterior of the nut body, said channel being provided with a sealing element; ∘ an inner sidewall and an outer sidewall extending between the first and second ends, the inner sidewall defining a bore opening at the first and second ends, said bore being sized to receive the tube therethrough; ∘ a fitting interface at the first end for engaging with the fitting component; ∘ a tube interface at the second end for fitting around the tube; and ∘ a channel extending through the nut body, between the inner sidewall and the outer sidewall, said channel providing a path for fluid between the bore and an exterior of the nut body, said channel being provided with a sealing element;