Reference Materials for Life Analysis

There have been a number of attempts to achieve this objective, but so far the challenge has not been fully met. This Chapter will examine some of the conventional approaches and then go on to consider how recent developments in the use of the Polymerase Chain Reaction (PCR) with DNA for the identification of species and individual organisms by DNA analysis, sometimes known as DNA Fingerprinting , have identified a yet unrealized need for a new dimension of certified reference materials. 

We will also review the development of chemical metrology in the pharmaceutical industry, an industry that is ever more closely related to molecular biology. The pharmacists first developed quality protocols and reference materials more than 40 years ago, quite independently of the activities of ISO and the REMCO Technical Committee. Only in the closing years of the 20th Century have these two important groups begun to realize that they share common objectives. 

---

Most matrix reference materials are regarded stable for their application within a certain time frame see also Section 2.2. They are usually produced in large batches designed to ensure that the same material is available for a number of years as well as to spread the high cost of production over as many units as is possible. The stability is closely monitored from initial production by the producer lot numbers or even individual unit numbers are allocated and the producers closely monitor, by regular analysis, the condition and quality of their reference materials over time. Because of such careful control, and to minimize waste, the tendency has been for producers to give a usable life from receipt to the customer, commonly 12-24 months. However, the producers can give this shelf life expectancy only for unopened units. 

Abstract Since the uncertainty of each link in the traceability chain (measuring analytical instrument, reference material or other measurement standard) changes over the course of time, the chain lifetime is limited. The lifetime in chemical analysis is dependent on the calibration intervals of the measuring equipment and the shelf-life of the certified reference materials (CRMs) used for the calibration of the equipment. It is shown that the ordinary least squares technique, used for treatment of the calibration data, is correct only when uncertainties in the certified values of the measurement standards or CRMs are negligible. If these uncertainties increase (for example, close to the end of the calibration interval or shelf-life), they are able to influence significant-... 

In a subsequent publication by the same group, solution nebulization ICP-MS was combined with particle screening and microsampling for analysis of individual particles (Esaka et al. 2013). Two methods were used for locating the uranium-bearing particles fission track analysis (FTA) and automated SIMS (described earlier). The particles were then manipulated inside a SEM and placed on silicon wafers and then dissolved for ICP-MS analysis. After method development and validation with particles from certified reference materials (NBL CRM U050, UlOO and U500) that were smeared on a cotton swab, a real-life sample collected at a nuclear facility was examined by both techniques. The measured ratio of the particles that were... 

---