Choice of vessel material is a key consideration in minimizing blank contribution for ultratrace analysis and long term performance. Milestone PTFE vessels are manufactured only from TFM, which is the highest density and thermally resistant form of PTFE available. Our vessels are pressed, not molded – which minimizes contamination during manufacturing. Unlike other manufacturers, Milestone does not use PFA, which has a limited temperature range (max. 210°C) and softens at high temperature, shortening its lifetime. Compare a Milestone vessel with any other manufacturer and it is immediately obvious that Milestone’s vessel quality and robustness is superior. In addition to TFM in some rotors, Milestone emplyes quartz vessels (Q-20 rotor) and inserts . Quartz is the ultimate vessel material for ultratrace analysis, since it can be cleaned more effectively, and has lower background levels than even extra high purity TFM.

Optional inserts, available in quartz and high purity TFM, fit inside the standard TFM vessels of the Medium/High pressure rotors, and expand the application range of the ETHOS EZ beyond any other microwave system thanks to Milestone’s exclusive “Vessel-in-vessel” technology. The quartz inserts are especially effective for difficult organics such as polymers and oils, since these samples can sometimes stick to Teflon walls and damage them during heating. Quartz inserts also enable higher weights of difficult organics (up to 1g) to be digested without causing the vessel to vent. The inserts sit in a water/H₂O₂ mixture, which produces O₂ during heating, which in turn converts CO₂ and NO_x produced during digestion to HNO_3, greatly reducing pressure build up in the vessel. An additional benefit is that as little as 1mL HNO₃ is used, which reduces reagent blank and allows analysis at lower dilution levels, improving detection limits.

Vessels are placed inside shields for support. Milestone shields are made only from PEEK, which can be cooled in a water bath if fastest cooling is required. Other manufacturers use Kevlar, which absorbs liquids and must be carefully dried when it gets wet: vessels with Kevlar shields cannot be water cooled.

35mL Quartz and Extra High Purity TFM Inserts

Designed for ultratrace analysis, these inserts are manufactured from extra high purity TFM or quartz for the lowest possible blank contribution. Maximum temperature is 300°C. These inserts fit inside standard 100mL vessels and can only be used with the SK rotors.

Microsampling Inserts

TFM and quartz microsampling inserts (3mL or 6mL) are designed for use with very small sample sizes and increase the capacity of a 12 position rotor to 36 positions. Maximum temperature is 300°C. Microsampling inserts fit inside standard 100mL vessels and can only be used with the SK rotors.