All you need to know about pH

The classical first year chemistry definition of “pH” refers back to Danish biochemist Søren Sørenson, who originated the term, alluding to the “potential of hydrogen ion.” Specifically, pH is the negative logarithm of the molar concentration of the hydrogen ion (H+) in the particular solution. This is usually expressed as a formula… pH = -log[H+]…

Gas Sampling From A Distance

Sometimes it is necessary to transport sample from some distance to the analyzer. There is no inherent problem in doing this, unless the sample is subject to condensation (see “Sample Conditioning” article); the analyte is unstable; or the interconnect tubing material might exhibit chemisorption properties. Recommended tubing:  Bev-A-Line IV (Polyethylene liner with ethyl vinyl acetate…

Sample conditioning

The term “sample conditioning” simply means the preparation of the gas sample containing your analyte to render it suitable for introduction into your gas analyzer. This is usually less of a consideration in ambient air monitoring applications than in source monitoring applications. When sampling from a source such as an industrial process, utility stack, or…

Recommendations on sample tubing

Back in the 1970s, many multi-point systems were being deployed, for monitoring carbon monoxide in parking garages and vehicular tunnels. Since long and otherwise exposed sample tubing runs needed to be installed, copper tubing was used. Because CO is not very reactive, and copper tubing is both flexible and robust, this was a preferred choice.…

Ethylene And Fruit Ripening

How about a little peak into the secret life of plants? Fruit ripening is a form of senescence and signifies the final stage in fruit development. Ripening, of course, eventually leads to spoilage, so there are important commercial reasons to increase and control post-harvest longevity. Complicating matters, post-harvest longevity varies naturally. Strawberries, for example, last…

Watch Out When Using A Zero Filter

Especially when doing low range work, it is important to make sure that your instrument is properly zeroed. Ideally, zeroing should be performed with a certified zero gas. However, mostly since it adds another step to the calibration process, this practice has somewhat fallen out of favor. The alternative to a zero gas requires that…