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Results of environmental methods are used to establish whether water is safe to drink or if an industrial or municipal effluent is in compliance with a permit. There is a concentration for each pollutant, called a Maximum Contaminant Level (MCL); the sample is analyzed by the approved method, and if the contaminant concentration is lower than the MCL, the water is good. Methods are designed to analyze many samples for one or more constituents in the shortest time possible. The methods are sometimes developed with almost total disregard for variability in matrices or simply assuming that all matrices are created equal.
For instance, a method approved for wastewater may have been validated using the required nine matrices, including all the required detection limit and recovery studies, but it still only applies to the matrices tested. There is no way the method can be applied to all matrices and, even if one matrix was a “sewage treatment plant effluent,” the method may not be applicable to all treatment plant effluents.
It is not possible for a laboratory to evaluate each matrix for potential interferences. Laboratory technicians are pressed to run as many samples as they can per day, and regulators do not allow method modifications anyway. (Limited method modification is permitted for wastewater at 40 CFR Part 136.6
and in some drinking water methods; however, once a modification is made, the laboratory applies the newly modified method to all samples.)
Method development organizations, such as U.S. EPA, ASTM
and Standard Methods, devise rapid methods with known accuracy and precision. The validation processes may vary, but all evaluate various matrices, sample preservation and holding times, interferences, and conduct interlaboratory trials to estimate single laboratory and multiple laboratory precision. Efforts are usually made to estimate accuracy, either by analysis of known concentration quality control samples or spiked sample recovery. Even with all these precautions, the method developed still only applies to the matrices tested and each method will usually say so.
In today’s world, laboratories are challenged to run thousands of samples as fast as they can, and the results are used to determine whether the sample is okay to drink or complies with a permit. Rapid methods are needed that are capable of maintaining these very high sample loads. Methods need to be standardized so that no matter who does the analysis or where the testing takes place, the results are similar. That said, care must be taken to ensure that chemical test methods are capable of analyzing samples the way they are and are not developed using samples as they are not.
You too can participate in the standardization process to revise existing methods and develop new ones. If you are interested in developing an Alternative Test Procedure (ATP)
for an existing EPA method, or perhaps in revising or developing a new method at ASTM or Standard Methods, contact me.
How to Select Laboratory Instruments
We buy laboratory instruments because we do environmental testing. We do this testing because the law requires it. This requirement by law is fundamentally different from other types of testing that measure the quality of a product. We do environmental testing because we have to, and we have to do the testing by methods prescribed by regulatory agencies.
Environmental regulations specify the methods. For example, the Safe Drinking Water Act
defines certain pollutants in drinking water and requires measurement by certain methods.
Similarly, the Clean Water Act
defines a set of methods to follow when analyzing wastewater.
Although SW846
methods are mostly guidance methods, RCRA
still lists methods and you are still required to run them to comply with solid waste regulations or contract requirements.
Why do laboratories run these methods? Obviously, a commercial lab runs samples in an effort to make a profit. A municipality may run samples for process control, or they may run them to prove that their stuff is below limits established by the EPA or another regulatory agency.
All methods require some kind of instrument. Even the simplest of laboratory methods will require a balance or some type of device.
So, how do you decide what you need? To do so, do not just look at your needs today. You need to think of next month, next year, and five years down the road. Do not replace what you have with what you have. Improve! Find the best fit. Find a manufacturer willing to consult with you. Let the manufacturer help you to decide what is best for you. Even if what is best for you is not their own product.
When choosing a laboratory instrument remember you are buying it to run a method. Your methods are prescriptions and have limited flexibility for modification. The instrument is, or contains, the detector. The detector is usually NOT included as one of the things that you can modify in an EPA method. Detector definitions can be very specific. You must use the same detector technology used during validation of the approved method. Make sure that whatever you buy is the same, or an allowed, technology.
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Method Validation
Manufacturers often go to voluntary consensus standard bodies (VCSB), such as ASTM, ISO, AOAC
or Standard Methods for the Examination of Water and Wastewater
to help create written standardized test procedures that use their new technique. Each organization has their own validation requirements, often written in documents only a statistician can understand. In addition, the validation procedure may be sufficient to satisfy the consensus organization, but regulatory agencies may not accept it. It is a difficult thing to spend thousands of dollars to validate a method that never attains regulatory agency approval.
Part of the problem is that the consensus standard organization volunteers almost exclusively focus on the inter-laboratory study as the method validation, or conversely they ignore the importance of validation. The inter-lab study is but a small part of method validation, much of which should occur as systematic steps during method development. The inter-lab study demonstrates, and documents, the between laboratory variability that occurs from differences in technique, reagents, and individual analysts. The inter-laboratory study does not measure accuracy, precision, selectivity, sensitivity, interferences, or “ruggedness”. These should all be determined before starting the inter-laboratory study.
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How to Price to Win
Pricing
is always a challenging decision particularly in mature markets where there are existing competitors and you are not the market leader. If you are not the market leader all of your products will be compared to the leader.
Pricing is always on value. A manufacturer may do “cost plus” pricing (% margin pricing is typical for product driven business to business marketing), however the purchaser ALWAYS buys on value. The value is not determined by the instrument manufacturer. VALUE is determined by the customer.
What the instrument manufacturer may believe is valuable may be of no value to a particular user/market. Also, different markets may perceive different features to have different value. One person may believe that a certain feature is of high value while another sees no benefit to that feature at all.
Value goes beyond the tangible product. Value is DEFINED as the extent to which a product or service helps the customer do more effectively, conveniently, or affordable a job they've been trying to do.
Value is quantifiable and is based on outcome or consequences. The product itself has value, but there are ALWAYS subjective assessments (beliefs) that add non quantifiable value. If there is an unmet need (a new instrument that does a new test), or one technology significantly outperforms “the old way”, then the new technology/product becomes the dominant feature/value differentiator.
If certain features provide economic benefits compared to a competitor, and if the benefit is quantifiable and proven. Then the feature that adds the extra value becomes a DIFFERENTIATOR worth a higher price.
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