Process sensors validation

Validation of Process Sensors under the 21st Century Initiative. 249... 

In this chapter we address the issues stemming from calibration and validation of process sensors that will be used or interchanged with analyzers. Technically speaking, the establishment treats them rather differently. For cahbration and validation issues, in most cases a sensor element may make up one component of the analyzer, and the overriding issue is where these instruments are going to be used (e.g., in the manufacturing suite). It is from this vantage point that we will treat sensors and sensor systems equally with analyzers. 

The objective of this chapter will be to propose a scheme for demonstrating the accuracy, precision, and suitability of sensors. As will be seen, no matter what sensor, device, or measurement approach is chosen, these three simple criteria will be at the heart of the calibration/validation exercise. Depending on the complexity of the process, the sensor system, and process requirements necessary to achieve a mechanistic understanding, more parameters may be necessary. For example, linearity, range, specificity, robustness, raggedness, detection limit, and quantification hmit may also need to be investigated. By definition (see calibration and validation definition in this chapter), accuracy, precision, and suitability will be the minimum requirements for the cahbration/validation exercise of process sensors. 

This chapter explores the fundamental meaning and rationale behind measurement and control mechanisms and hopefully will lead the reader to view calibration and validation of process sensors as a very different exercise than the one that most analytical minds working in regulated industries have previously experienced in the laboratory. 

Under these practices then, calibration and validation of process sensor elements, sensors, and sensor systems used in a pharmaceutical manufacturing facility would have to be... 

The elements of calibration and validation of sensor systems are thus composed of all of the physical attributes that make up sensor systems, the functional aspects that determine the operational capability of these systems, and finally the parameters that determine the frequency of verification, the sensor system variables that determine the operational range, and the process/sensor standards that will be used during the verification phases of the sensor systems. 

VALIDATION OF PROCESS SENSORS UNDER THE 21ST CENTURY INITIATIVE... 

I Validation of process sensors is verified by demonstrating the suitability of the measurement to some uncontrolled variation shown to be the result of an assignable cause arising from physicochemical changes in the process material. SPC and chemomet-ric, multivariate analytical approaches can be applied to cause the sensor to direct the process critical control parameter (PCCP) into a satisfactory state of minimum variance. 

With respect to cGMPs that will be used to regulate how process sensors will be calibrated and validated, new application and architectural schemes are being proposed for the design, qualification, installation, operation, and maintenance of in-line and on-line sensors. 

Comparison between Traditional Calibration and Validation Strategy for Laboratory-Based Instruments and Process Sensors and Analyzers... 

Provides new chapters on diffuse reflection theories, the calibration and validation of process sensors, and the NIR spectra of gases... 

This oxygen sensor system has been successfully used by us with a number of different types of packaged foods and packaging processes, being continuously developed and optimized in these real-life conditions and applications. It was validated in several small laboratory scale and medium industrial scale trials19,30 with the following foods and processes ... 

In the following, the diagnosis method has been validated using a data set of 2 weeks, with a serie of on-line measurements every 30 minutes (see Figure 10). During this period, dynamical changes were imposed on the process through Qin, the feed flow rate, while the input concentrations i.e., CODin and Zin) were supposed to be constant. However, no on-line measurements were performed on these variables so only intervals for the values of CODin and Zin are known. Moreover, several faults occurred on different on-line sensors ... 

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