To provide a protective coat on a refrigerated sample collector for a corrosive environment a unitary frame includes a support unit with condenser and evaporator coils mounted to the support unit and an orifice connecting the condenser and evaporator coils. The evaporator coils, condenser coils and restrictor are powder coated after being connected, whereby an effective seal is provided for the restrictor, condenser coils and evaporator coils after they are assembled to the support. The unitary frame can be easily removed or connected as a unit to the sample collector. A peristaltic pump may be used for drawing at least one sample into the refrigerated sample collector and depositing said sample into at least one sample bottle. The peristaltic pump may include contoured tube guides to reduce movement of the peristaltic pump as a roller paddle rotates.