Fusion monitors are a novel quality control tool to monitor the fusion process, the bias between fluxer's positions, the bias between different fusion instruments and the bias between platinum molds.
WHY IS XRF QUALITY CONTROL ASSURANCE IMPORTANT?
Analytical laboratories that provide XRF analytical data are affected by requirements of quality, since chemical measurements support important decisions in production and commercial areas. Laboratories must contribute towards assuring the quality of their data.
Production laboratories always design and implement internal XRF analytical quality control processes and monitoring procedures to ensure that their XRF results are consistent, accurate, and within the specified limits of precision and accuracy. As such, quality control processes and monitoring procedures are an important determinant of the quality of XRF analytical data, and are recognized as such by ISO/IES 17025:2005 and the Australian Standard AS 2563-1996.
WHY USE FUSION MONITORS IN THE ROUTINE QUALITY CONTROL PROCESS?
The monitoring of the Fusion-XRF analytical process is always undertaken by the inclusion of specific control materials into the XRF analytical sequence. If the analytical results fall outside pre-set laboratory acceptable limits and the Fusion-XRF analytical process is unusable until the problem is diagnosed and fixed.
Error sources can be grouped into three interrelated groups and a drift from one component influences the whole Fusion-XRF process and causes important analytical result biases:
XRF spectrometer: XRF tube, alignment, detectors, crystal, sample holder, other electronics¦
Fusion process: Fluxers, fusion temperatures, individual fluxer position, platinum molds¦
Sample preparation: Calcination, sample, flux, additives, weighing, reference materials¦
Control samples are ideal for the quality assessment of the overall Fusion-XRF analytical process. However, they do not allow for monitoring and diagnosis of the individual error sources. XRF drift monitors are available to make routine monitoring of the XRF calibration curve and XRF drift corrections. To complement the control procedure of the different parts of the analytical process, Claisse has introduced the Fusion Monitor for quick, easy and proactive quality assessment and monitoring of the fusion process. Now, laboratory analysts have three complementary tools to proactively monitor the whole Fusion-XRF analytical process.
WHAT ARE FUSION MONITORS?
Fusion monitors consist of homogeneous, pre-fused spherical glassy beads each composed of lithium borate fluxes, a non-wetting agent and a matrix (cement, iron ores, etc.). Being already pre-fused together, the matrix is stabilized and protected from chemical and physical effects that could alter its characteristics. Also, there is no need to weigh all the components separately. In fact, fusion monitors are independent of the sample preparation step and are ready to be fused directly from the bottles.
WHAT CAN FUSION MONITORS DO FOR YOU?
The use of fusion monitors is based on comparison. The measurement obtained from a given fusion monitor preparation is compared to a reference value that was obtained from the preparation of the same fusion monitor specimens under an initial set of conditions (fixed fusion time, platinum mold, fusion instrument, fusion position, etc.). In routine practices, fusion monitors allow for quick and error-free assessing of:
Stability of the fusion process: It is important to validate the long term stability of the fusion process. Fusion monitors keep track of the fusion stability over time and allow to quickly and instinctively raise a flag when any result falls outside a pre-set acceptance limit. Corrective actions can then be taken immediately to solve the source of variability.
Wear and tear of the platinum molds: The platinum mold effect is caused by irregularities of the mold surface, such as warping and scratching. It can generate significant analytical biases that can be easily and proactively determined and monitored by regular using fusion monitors. Fusion monitors indicate when polishing or reshaping procedures must be performed, thus saving time and result uncertainties.
Temperature bias between the fluxer positions: Uniform position-to-position heating is essential to get reproducible results. However, fusion conditions could differ between the fusion positions on an automated fluxer, especially with older fluxers that may have developed mechanical wear. When regularly used, fusion monitors indicate the temperature differences between the fusion positions so that appropriate actions can be taken to correct the drift of temperature.
Temperature bias between the different fluxers: Fusion conditions could differ between the different fusion instruments, especially in high-production laboratories where many fluxers are often operated at the same time. Regularly used, the fusion monitors denotes instability of an instrument compared to the others. It can provide important leads to identify the preventive or corrective maintenance needs to obtain the same results as the other fluxers.
WHAT ARE THE BENETIFS OF USING FUSION MONITORS?
MINIMIZE OPERATIONAL DOWNTIME
Analytical results may be affected by a large number of factors inherent to the Fusion-XRF analytical process. Identifying the source of a problem when the control samples are outside the specified range is a time consuming process. Not only are fusion monitors efficient in problem diagnosis and troubleshooting, they avoid important operational downtime which are extremely costly for production and commercial laboratories.
PREVENT INCOMING RESULT BIAS
Fusion monitors allow to quickly detect biases coming from the fusion process and to take proactive actions to correct pending problems before the XRF results become unusable.
MAINTAIN CONSISTENCY OF THE ANALYTICAL RESULTS
Fusion monitors allow maintaining result consistency by overlooking and correcting the analytical biases. Therefore, this quality control tool avoids running a long series of biased analysis. In fact, unnoticed biased analysis may affect manufacturing and commercial decisions and lead to improper elemental composition of an entire production batch for example. Such a problem may have important financial impacts for a company.
WHY IS THE FUSION MONITOR SO SPECIAL?
NO MANIPULATION ERRORS
Since the matrix, the non-wetting agent and the flux are already merged, our fusion monitors are stable and homogenous; no need to preserve them in special conditions, no need to add any additives, no need to calculate LOI and no need to weigh the sample and the flux precisely as you would when running reference materials control samples. The fusion monitors are ready to be fused straight out of the bottle.
EASY TO USE
Roughly weigh a certain amount of Fusion Monitor into a platinum crucible, perform a fusion using the same fusion program as in your routine operation and analyze the glass disk.
NO NEED FOR HIGHLY-QUALIFIED PERSONNEL
Fusion Monitor is ready for fusion straight out of the bottle to allow diagnosing biases between molds, variability between fluxer positions, variability between different fusion instruments and to plan corrective actions.
Fusion Monitor can be used with any fusion instrument. It also can be used regardless of the flux brand and composition you use to prepare your samples. Also, the Fusion Monitor can be used even if the sample to flux ratio of the laboratory routine samples is different from that of the fusion monitor specifications.