The increasing stringency of the regulations and quality control guidelines that are applicable in many analytical and process control laboratories means that more and more systems that were previously taken for granted, such as the water purification system, must undergo routine validation. This article looks at what is involved in such validation processes and describes how in practice a modern laboratory ultra pure water system incorporates these requirements.
Just as in pharmaceutical production facilities, laboratories involved in pharmaceutical quality control and drug discovery are now becoming subject to closer scrutiny and are required to operate within the various guidelines that are an integral part of a regulated industry.
Generally speaking, most laboratories operate within their own procedures, which should be both documented and audited, both internally and externally to an ISO or NAMAS accredited standard.
The move towards formal validation of both the water purification equipment and the quality of purified water produced is a step towards harmonising company procedures and ensuring the same standards and protocols follow on from research through pilot production to full scale manufacture.
Validation can be defined as having 'documented evidence to ensure with a high degree of certainty that a product is operating consistently to the stated specifications'.
To achieve this objective, a number of 'qualifications' and 'specifications' are defined. These refer to the performance of tests and procedures to ensure that a specific item or performance parameter conforms to the agreed specification.
In summary, validation simply means providing written evidence that the users are indeed receiving consistently what they think and expect they are receiving in terms of water quality.
The various qualification protocols are the agreed procedures to test, maintain, service and calibrate the equipment, as prescribed by the manufacturer, in order to ensure that the product continues to function to specification.
Typically with each item of water purification equipment, a Validation Support Manual should be supplied. This should contain all of the relevant information to enable the user to validate the system. Typically the manual should contain the following sections: Qualification Plan (QP); Installation Qualification (IQ); Operational Qualification (OQ); Performance Qualification (PQ); Service/Maintenance Requirements; Standards and Certificates.
Qualification plan
The objective of the Qualification Plan is to detail and explain the approach to the validation of the specific product or system. As well as explaining the various 'qualifications' and protocols, it should also define the procedure for reporting and dealing with any deviations identified during the validation.
Installation qualification
The Installation Qualification is designed to check methodically the various installation requirements, particularly in respect of feed-water and environmental considerations.
Operational qualification
The Operational Qualification will provide documented evidence to demonstrate that the equipment operates as intended in all of its various functional modes, including special procedures, such as cleaning and sanitisation.
Performance qualification
The Performance Qualification will provide documented evidence that the product water quality continues to achieve the desired specification. Tests are performed both initially during commissioning and on an ongoing basis, depending on user requirements.
Maintenance contract
An integral requirement of all laboratory water purification equipment is to ensure that it continues to provide the desired quality of water on an on-going basis. In this respect a service schedule must be developed and applied to enable key operational parameters to be checked and documented.
Typically these will include the routine changing of consumable items, such as filters, but also re-calibration of the various in-built water quality sensors. These are calibrated using substitution boxes containing standards, which are directly traceable to national reference standard.
Standards and certificates
An important section in the Validation Support Manual is reserved for inclusion of the various Certificates of Conformity and Certificates of Calibration generated during the manufacturing and quality control procedures. These signed certificates act as documented evidence that the product was manufactured to the specifications and instructions laid out in the product master file and that it has been demonstrated to perform as originally intended.
Additionally, Certificates of Compliance are included, which are formal documentation that the product has passed the various testing required to achieve the appropriate certification, for example, electromagnetic compatibility, CE certification and ETL certification (relevant to North America).
As well as the Validation Support Manual, the latest generation of water purification units have a number of in-built features to assist the user in the product validation and to assist in compliance with good laboratory practice (GLP).
Purification techniques
To achieve the very high degrees of water purity required in modern laboratories, multi-technology approaches are required. These enable specifications to be achieved economically and consistently. At the same time, the system must be able to cope with a wide range of feed-water types and conditions.
Typical technologies used are: microfiltration; ultrafiltration; reverse osmosis; ion exchange; UV irradiation; adsorption.
One of the most significant approaches to achieve both high quality and consistently high purity is that of multi-stage monitoring (Figure 1 a, b). This process, which is incorporated into the Purelab Ultra, includes an additional final polishing stage, which eliminates any water quality variations during the exhaustion of ion exchange media.
On systems only fitted with product water monitoring, impurities can be present in the product water due to the hysteresis between the absolute water quality and the alarm trigger point. By adding a further purification stage after this, even easily eluting contaminants are removed (Figure 2). Not only does this give confidence in the final water quality (Figure 4), but it also minimises operating costs and significantly improves the convenience of operation since the exhausted primary deionisation cartridge can be replaced when convenient, rather than immediately, which could be disruptive to other laboratory work.
The latest range of high purity water purification units released by ELGA LabWater have been specifically designed not only for ease of use and ultimate, consistent high water quality, but also to assist the user in achieving their validation requirements.
