Reagent vessel for storing a liquid reagent

A reinforced bulge-resistant reagent vessel for an analytical instrument, wherein the reinforced bulge-resistant reagent vessel is configured to store a liquid reagent, the reinforced bulge-resistant reagent vessel defining a substantially rectangular shape and comprising:

• a cover;
• and
• a lower part secured to the cover, wherein the lower part comprises a bottom wall, a front wall, a rear wall, two opposing side walls that together define the largest surface area of the bulge-resistant reagent vessel, at least one separating wall and at least one connection wall the latter of which is placed substantially one third to one half of a distance between the front and rear walls, wherein the cover, the bottom wall, the front wall, the rear wall, the at least one separating wall and the two opposing side walls define at least one internal volume for storing at least one liquid reagent, wherein the two opposing side walls are connected to one another by the at least one connection wall and the at least one separating wall both of which are located within the at least one internal volume along their respective edges over a substantial majority of the height of the side walls to define an uninterrupted monolithic construction between the two opposing side walls in order to provide reinforcing rigidity to them, wherein the connection wall is spaced apart from the bottom wall by a distance of 2.0 to 30.0 mm, and wherein the connection wall, the at least one separating wall and at least the two opposing side walls are injection-molded and monolithically formed along such edgewise length.