Interlaboratory studies to improve the quality of mercury determination in seawater

Determinations of pollutants in various matrices are routinely performed by a number of organizations for monitoring contamination levels of the marine environment. Projects for improving the quality of determinations of trace metals in seawater have been successfully concluded within the scope of the BCR-Programme (now renamed Standards, Measurements and Testing Programme) of the European Commission; however, the determination of total mercury could not be considered at this stage both because of the poor analytical performances observed and the unsuitability of the containers (polyethylene) used for the seawater certified reference material (CRM 579). A specific project has therefore been organized to improve the state of the art of Hg determination in seawater and to investigate the best way of storing a candidate CRM. Two interlaboratory studies have been concluded and a certification campaign has now started. The materials have been collected in the Southern Bight of the North Sea, carefully prepared (filtered and acidified) and their homogeneity and stability were verified. This paper presents the results of the two interlaboratory studies.     

Interlaboratory study to improve the quality of trace element determinations in rainwater

This is the first publication which describes the development of a reference material (RM) for the determination of 11 trace elements (Cu, Pb, Mn, Ni, Zn, Fe, Cd, Co, V, As and Al) in rainwater at microgram per liter concentrations. An interlaboratory comparison study for the determination of trace elements in rainwater was carried out for material performance studies to establish analyte concentrations with a stated uncertainty. Fifteen reputed laboratories from Asia, Europe and North America participated in the study. These laboratories used their regular in-house methods to analyze the rainwater samples. The aim of this study is to establish concentration levels of trace elements in rainwater based on interlaboratory study results. Details of the production, homogeneity and stability of the reference sample are given in this article. The organization of the study and the quality assurance measures undertaken at the organizer's laboratory are described. The analytical results obtained from individual laboratories and the analytical methods used for the determination of trace elements in rainwater are discussed. Based on the results obtained from the intercomparison study, certified values as well as informative values are assigned to the 11 trace elements in rainwater.     

Step-by-step implementation of a quality system in the laboratory

In recent years laboratories have undergone huge transformations due to the technological development of inspection and testing equipment; the introduction of computerised and automated systems; keen competitiveness between companies/laboratories as a result of demand within Europe and on the international market; and greater consumer awareness of the quality of the products available. Laboratory accreditation, though a voluntary process, is formal recognition by an accreditation body of the laboratory's competence to carry out certain tests. This article presents those aspects which should be taken into account in the step-by-step implementation of a quality system and also makes reference to the requirements for the operation of accredited laboratories in accordance with European Standard EN 45001.     

Implementation of a quality system in a clinical laboratory

The effects of a quality system are measured with the aid of quality indicators, which can be used for both decision-making by the management of the laboratory and for process control. The need for economic appraisal is stressed since the development of a quality system is very time- and labour-consuming. The aspects of both the customer and the personnel involved should be considered to evaluate the quality system. It is also important to define practical means to build up and maintain a quality system especially in smaller laboratories. For instance, simple tools to evaluate uncertainty of measurement and availability of inexpensive national reference materials are needed.     

Collaborative study to improve the quality control of trace element determinations in polymers. Part 1. Interlaboratory study

In order to control the quality of trace element determinations in polymer, the Standards, Measurements and Testing Programme (formerly BCR) of the European Commission has started a project of which the final aim is to certify polymer reference materials for their contents of a range of trace elements. The first part of this project consisted in an interlaboratory study which aimed at testing the feasibility of preparation of candidate polymer reference materials and to detect and remove most of the pitfalls observed in trace element determinations. This paper presents the results of this interlaboratory study carried out prior to the certification campaign. Received: 22 April 1999 / Revised: 21 June 1999 / Accepted: 21 June 1999     

Collaborative study to improve the quality control of trace element determinations in polymers. Part 1. Interlaboratory study

In order to control the quality of trace element determinations in polymer, the Standards, Measurements and Testing Programme (formerly BCR) of the European Commission has started a project of which the final aim is to certify polymer reference materials for their contents of a range of trace elements. The first part of this project consisted in an interlaboratory study which aimed at testing the feasibility of preparation of candidate polymer reference materials and to detect and remove most of the pitfalls observed in trace element determinations. This paper presents the results of this interlaboratory study carried out prior to the certification campaign. Received: 22 April 1999 / Revised: 21 June 1999 / Accepted: 21 June 1999     

Interlaboratory comparison to evaluate a standardized calibration procedure for the headspace analysis of aromatic solvents in blood

The determination of volatile organic compounds in blood by headspace gas chromatography is one of the central and long-established analytical techniques in occupational medical biomonitoring. Nevertheless, the relatively low success rate in intercomparison programs shows that the headspace technique is insufficiently standardized. A critical stage of the analytical procedure seems to be the preparation of calibration standards in biological matrices. As part of an extensive interlaboratory comparison by the Analyses of Hazardous Substances in Biological Materials working group of the DFG Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, three typical procedures were compared with one another using typical aromatic solvents as an example. The best correlations between the participating laboratories and the best results for the analyses of samples from interlaboratory comparisons were obtained when highly concentrated stock solutions of the aromatic compounds in ethanol were first diluted with physiological saline and then used for spiking horse blood in headspace vials. This procedure can be easily standardized and is therefore recommended by the Analyses of Hazardous Substances in Biological Materials working group for the preparation of headspace calibration standards for aromatic compounds.Dr. Regine Heinrich-Ramm, our highly valued colleague, died in 2002From the Analyses of Hazardous Substances in Biological Materials working group of the Analytical Chemistry Group (Chair: J. Angerer, Erlangen) of the DFG Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (Chair: H. Greim, Weihenstephan)     

On the use of polycapillary structures to improve laboratory Energy-Dispersive X-ray Diffractometry and Reflectometry

One of the major limits of the laboratory X-ray sources is represented by their low photon flux which induces many researchers to move to synchrotron beamlines. From this point of view, polycapillaries lenses represent an extraordinary tool to improve the performances of laboratory machine and, indeed, several models of polycapillary optics-based instruments, such as diffractometers, spectrometers etc., are currently available on the market. In this work, the application of polycapillary optics to a particular kind of non-commercial X-ray instruments, namely the Energy-Dispersive X-ray Diffractometers and Reflectometers, is proposed. The advantages and limits of the use of polycapillaries are discussed and the results of preliminary experiments are shown.     

ISO compliant laboratory quality systems and incident monitoring improve the implementation of laboratory information systems

Quality systems can provide a means of measuring the rate of occurrence of defined incidents and non-conformities. We have studied the application of laboratory quality systems to monitoring the implementation of laboratory information systems (LIS) in two similar size tertiary hospital pathology laboratories in Australia. At one site, one department implemented a quality system accredited to ISO 9001–1987 and ISO 9001–1994 while the rest of the organisation did not have a formal quality system; this site implemented the Cerner PathNet LIS. At the other site, the organisation was in the process of implementing ISO/IEC Guide 25–1990 and ISO/IEC 17025–1999; this site implemented the PJACC AUSLAB LIS. The rate of quality system incidents and non-conformities was used to track the progress of implementation of the LIS. We found that different quality systems appeared equally useful in monitoring the rate of occurrence of incidents. However, the presence of a formal quality system greatly improved the proportion of incidents that could be investigated and resolved at root cause level. Incident monitoring, as part of a formal quality system, proved to be a useful tool in monitoring and managing the implementation of these LIS. Received: 4 August 2001 Accepted: 21 March 2002     

Czechoslovakian biological certified reference materials and their use in the analytical quality assurance system in a trace element laboratory

Summary The Trace Element Laboratory of the University of Agriculture in Prague (CSFR) participated successfully in interlaboratory experiments on the determination of the contents of trace elements in seven Czechoslovakian reference materials. Czechoslovakian certified reference material CRM 12-02-01 (Bovine liver) was used for the development of a new analytical method using the Dry Mineralizer Apion as well as in analytical quality assessment of data in the determination of Cd, Pb, and Hg contents in routinely analyzed animal tissues.     

Basic steps towards a self-sustainable quality system and laboratory accreditation

 Laboratory managers are facing the task of altering the attitudes of themselves and their employees in order to implement a quality lifestyle, which is the prerequisite for successful implementation of a quality system complying with appropriate international standards. The alterations require a painstaking and constructive approach. Not all laboratories have the resources to secure the assistance of quality consultants. For those laboratory managers who have to find their way towards quality management on their own, some recommendations are given for a path towards a self-sustaining quality system. Several practical aspects of the basic steps in this path, which starts with assessing the current status of the laboratory and is followed by awareness building, are discussed. The recommendations are derived from the experience of the authors in their own laboratories. Received: 5 June 1997 · Accepted: 7 December 1997     

EQUIP: a worldwide program to ensure the quality of urinary iodine procedures

In 2001 the Centers for Disease Control and Prevention (CDC) established a program, Ensuring the Quality of Urinary Iodine Procedures (EQUIP); to assist laboratories around the world and assess the accuracy of their urinary iodine (UI). CDC designed EQUIP to issue unknown specimens to participating laboratories three times per year. Each laboratory was asked to analyze unknown samples in duplicate on three different days. During the first five rounds of EQUIP, 41 laboratories participated, measuring unknown samples and reporting their results to CDC. CDC used these results to prepare a statistical report for the laboratories. Feedback to the laboratories provided external confirmation regarding performance. As a group, laboratory performance improved; several laboratories made considerable improvement. Several laboratories that showed no improvement have ordered new equipment or are arranging for additional training. EQUIP is a key tool used to support laboratory quality assurance in an effort to eliminate iodine deficiency disorders (IDD) in the world.

Filtering and integration of chromatographic data: a tool to improve calibration?

The effect of filtering and automated integration of chromatographic data on the calibration curve and detection limit was assessed. In a first approach simulated chromatograms were used to quantify the effects of data processing. Three types of filters were used: Savitzky-Golay, Fourier and Wavelet filter. The filter parameters chosen have been optimized in a previous study. The simulated data have been integrated by a commercial software package. The use of applying the DIN 32645 concept for the determination of the detection limit of chromatographic data is discussed and opposed to the concept of the method detection limit. Under the conditions investigated, filtering can improve the limit of detection up to a factor of three. This can be explained by the fact that filtering reduces the variance of the peak area and height and the limit of detection is mainly determined by their variance. However, the integration algorithm practically limits the possible improvements by filtering the data.     

Interlaboratory programme for the quality control of trimethyllead determination in the environment

Determinations of the trimethyllead moiety in environmental samples are carried out by a number of laboratories in Europe. To verify the quality of such determinations, the Measurements and Testing Programme (formerly BCR) of the European Commission organised an interlaboratory exercise which allowed discussion and comparison of the different techniques used so far in lead speciation analyses. In addition, this first step enabled a study of the feasibility of the preparation of candidate reference materials (CRMs) for the determination of the trimethyllead moiety in simulated rainwater to be carried out. The solutions used in this study were carefully prepared and their homogeneity and stability verified. This paper describes the organisation and the results of the intercomparison and discusses the further development of the project.     

Plans for implementation of a quality system in the control laboratory of the Romanian National Medicines Agency

This paper describes the practical implementation of a quality system in the control laboratory of the National Medicines Agency, Romania, the main aim being the alignment of the requirements of the control of drugs in Romania with European Union standards. Activity in this field is relatively new in Romania, however, it is of great importance to Romania’s compliance with international standards. Received: 13 September 2000 Accepted: 19 February 2001     

Verification of results to improve the quality of analytical data: a proposal

After some two decades insisting on validation and normalization of methods, the reliability of the results in analytical chemistry continues to be unsatisfactory. Further, the processes involved are too slow, with the effect that frequently the most relevant results are obtained with methods not (yet) validated according to norms. It is time to rethink about how the reliability of the results could be improved. It is proposed to shift some of the control from the validation and normalization of method to the verification of the results, using verification tools built into the procedure: additional standards may enable the calculation of the yield of an extraction or chemical transformation, control the column performance or ensure that the fraction from a preseparation is correctly cut. Such verification tools provide control for every sample. If the correctness of results is verified for every sample, this confirms the adequate performance of the method and could replace a corresponding part of the validation. Examples are shown for a number of methods.