Lowest Blanks Over Long Time of Usage

To perform highly precise trace elemental analysis it is necessary to keep the blank values as low as possible and to minimize all sources of analytical error. This report shows that HVT50 vessels and F100 liners made from high-purity PTFE-TFM provide low blank levels over a long time of laboratory use and are not a limiting factor for highly precise measurements.

Introduction

Analytical chemists fear the contribution of analytes from sources other than the sample as these will be a difficult to identify source of analytical error. The so-called blank values can be caused by the process reagents as well as by laboratory dust or by all materials that get in contact with the sample or reagents.

For acid digestion instrumentation a possible source of contamination may be the material of the pressure vessels. There can be contamination, which is present in the bulk of the vessel material and will be leached out during use.

There can also be a contribution by a "carry-over" of adsorbed traces of certain elements from a sample with high analytes concentration into a sample with low analytes concentration.

Sometimes it is suspected that due to aging of the surface by the ongoing chemical attack the polymer surface may deteriorate and increase carry-over effects with extended usage.

This report demonstrates the high purity of Anton Paar´s digestion vessels by using the HVT50 vessels in a Multiwave GO: To assess possible sources of contamination pre-cleaning of the vessels and blank digestions were performed under cleanest possible conditions of the application laboratory. Vessel operation was done under the fume hood using supra-pure acids.

Additional two more runs were performed under the cleanest possible conditions in the partner laboratory which also did the subsequent analytical testing. The vessel handling was performed under laminar flow conditions using sub-boiling acids.

No matter if the vessels were new or extensively used for more than two years in the lab, the blank values were for most elements below the detection limits of a modern state-of-the-art ICP-MS system.

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