Informing Spectroscopists for Over 40 Years

Quality Matters Columns

The 33rd meeting of the Reference Material Committee of ISO, ISO/REMCO was held in Hangzhou (China) from 3 to 7 May 2010, and was hosted by the Standardisation Administration of China and the China Association of Standardisation. ISO/REMCO now has a membership of 70 members of the International Organisation for Standardisation (ISO) and liaison with 18 international organisations and seven ISO-internal committees. The new ISO TC liaison introduced at this meeting is with ISO/TC 158 “Analysis of gases”, with Dr Adriaan van der Veen acting as the REMCO liaison officer.

Peter Jenks

the Jenks Partnership, Newhaven House, Junction Road, Alderbury, Salisbury, Wiltshire SP5 3AZ, UK

ISO 17025 has been with us now for 12 years and in some industry sectors it is getting hard to find a commercial laboratory offering chemical testing that is not accredited to ISO 17025 for some or all of its scope. In just 12 short years the importance of “quality management” to a laboratory has undergone a seismic shift.

ISO Standard ISO 17025 is the cornerstone of the “Measured Once, Trusted Everywhere” concept and the accreditation of labs and testing establishment to ISO 17025 by accreditation bodies underpins the credibility. ISO 17025 is all about facilitating the free movement of goods and services and so helps to eliminate monopolies, cartels and all sorts of anti-competitive activities.

Continuing the series of articles on spectroscopy, we return principally to the UV-visible area of the spectrum, but this time to the science of luminescence (fluorescence and phosphorimetry), in all its many forms. Given the diversity of the application areas and instrument types available, in such an article we can only briefly give an overview of the topic and interested parties are, therefore, recommended to follow-up the listed references for more in-depth discussion on the points raised.

John Hammond

Starna Scientific Ltd, 52–54 Fowler Road, Hainault Business Park, Hainault, Essex, IG6 3UT, UK

The Irish writer George Bernard Shaw once said: “England and America are two countries divided by a common language”. Whilst this statement generally refers to the over 4000 words in everyday use in the United States that are not in British English, in the scientific world “is it metre or meter”, or for spectroscopists, nanometre or nanometer?

Peter Jenks

the Jenks Partnership, Newhaven House, Junction Road, Alderbury, Salisbury, Wiltshire SP5 3AZ, UK

The 12th Biological and Environmental Reference Material symposium (BERM 12) is now over: held at Keble College, Oxford, UK, from 7 to 10 July 2009 it was, based on the feedback received, a resounding success, both scientifically and socially. The weather was perfect and the setting magnificent.

The summer of 2009 has been notable for two metrologically significant events: the annual meeting of the ISO REMCO Committee and the 12th BERM Symposium, neither of which has ever been held before in the UK. It is a massive credit to LGC that they were able to host both meetings and succeeded in making the BERM Meeting one of the best ever! In this column John Hammond, the UK Industry Delegate to ISO/REMCO, reports on the proceedings and decisions of the meeting. I’ll be reporting on BERM 12 in the next column and also explaining the relationship between the UK Reference Materials Working Group, the BSI and ISO/REMCO. — Peter Jenks

Where is the accreditation of analytical laboratories taking the reference material producer industry? I’ve recently been cogitating the long term impact of the growing spread of ISO 17025 accreditation on the development and supply of certified reference materials and I’m concerned that the “quality business” is driving laboratory accreditation into areas where reference material producers will be under increasing pressure.

Following on from our previous foray into the UV-visible area of the spectrum, in this article we discuss its nearest neighbour in the spectral scale, namely near infrared (NIR) spectrometry. The NIR spectral region lies between 780 nm and 2500 nm (4000 cm–1 to 12,800 cm–1) bridging the more well-known and analytically used regions of the UV-visible (190–780 nm) and the infrared (4000–600 cm–1).

Until relatively recently, it has been called the “forgotten”’ region. However, the arrival of FT-NIR instruments in the 1990s and the increasing awareness of the NIR’s unique information content in the signal that can provide both physical and chemical information, deployment of NIR spectrometry systems for both qualitative and quantitative purposes has become wide spread, particularly in the pharmaceutical industry. An overview by Barton of the theory and principles of NIR spectroscopy is readily available1 and more recently by Workman. These applications in the NIR have led to new standard practices for using and qualifying spectrometers being generated by ASTM.

Once again, as in the UV-visible area, many of these changes have been as the result of demand in specific areas, and a requirement to find solutions to defined problems. This renewed interest, particularly in the pharmaceutical industry, has led to the need for traceable standards for the calibration and qualification of the wavelength scale of NIR spectrometers in the regulated environment. Because of the versatility in the sample presentation modes in the NIR, there is a need to ensure wavelength accuracy in transmittance, reflectance and transflectance. For dispersive instruments, wavelength precision is also important because of the use of mechanical wavelength drives. However, for modern FT instruments the precision is so good that it is only the accuracy of the wavelength scale is important.

The wavelength scale accuracy is important because of the excellent signal-to-noise ratio of the NIR especially in the region above 1200 nm. This facet means that small changes in the spectral response function are spectroscopically significant and hence transfer of spectral information between different NIR systems becomes problematic if the wavelength shifts, amongst others, are not controlled. Regulatory interest has lead to the promulgation of monographs for the specification, calibration and control of NIR spectrometers in both the United States and European Pharmacopoeias. Unfortunately these monographs have not been harmonised and there are significant differences.

In the area of instrument qualification, we will look briefly at two aspects which continue to cause problems, namely wavelength calibration and absorbance/transmittance accuracy.

Christopher Burgess

Burgess Analytical Consultancy Limited, “Rose Rae”, The Lendings, Startforth, Barnard Castle, Co. Durham, DL 12 9AB, UK

John Hammond

Starna Scientific Ltd, 52–54 Fowler Road, Hainault Business Park, Hainault, Essex, IG6 3UT, UK

Introduction

Following on from our overview “Standards for the 21st century–establishing trust in measurement” this article discusses the changes that have occurred within one of the oldest instrumental spectroscopic techniques, namely UV-visible spectrometry.

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