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7 • TIP Photovac announces a new design concept in direct Where specificity, along with the advantage of immediate reading instruments to serve the Safety Specialist. We assessment, is a requirement, the Safety Specialist can started with our exclusive photoionization detector (PID), turn to Photovac's portable gas chromatographs which which performs so reliably in our portable gas have been satisfying a wide variety of application needs chromatographs. Of the detection options available, the over many years. PID is increasingly favored due to its higher overall sen- There are, however, many monitoring tasks of complex sitivity when compared, for example, to flame ionization environments where the objective is to make an im- detection (FID). Also, the PID requires no hazardous mediate assessment without specificity. These include consumables, such as the hydrogen used in an FID. "scoping" determinations, leak detection, accidental spills, waste site evaluation, environmental surveys and As a direct reading instrument, TIP* offers the highly emergency response. Additionally, there are the evalua- desirable feature of supplying "real time" data in the tions of cases in which there is only one toxic compo- monitoring of gas or vapor concentrations. This permits nent present; TIP' is a highly appropriate tool for many the Safety Specialist to make an immediate assessment of these monitoring tasks. of contamination levels, at sub part-per-million levels if necessary, without having to endure the time delay Having added an attractive and practical package of afeatures, dictated by user preferences, the result is the associated with the use of trapping techniques requiring • TIP*: an innovative breakthrough in direct reading in- lab analysis and consequent delayed results. strument design, incorporating a maximum of desirable features at an affordable price! TIP '` The name TIP' stands for Total lonizables Present. Our increases the lamp's operating life but also reduces instrument is designed to measure any airborne contami- replacement costs to a fraction of that of its high voltage nant which is detectable by photoionization. In PID counterparts. technology, an ultraviolet light source is used to ionize the molecules of chemical substances which are in the In T/P"s operation, a small pump continuously draws gaseous or vaporous state. The ions are collected on sample air into an ionization chamber which is flooded positive and negative electrodes, resulting in a flow of with ultraviolet light. The molecules of most light perma- current proportional to the concentration of the contami- nent gases (including the air gases; hydrogen, helium, nant. Whether or not ionization takes place depends nitrogen, etc.) are unaffected as they require an ioniza- upon the minimum energy required to produce ions, tion energy higher than that generated by the lamp in which is different for each chemical substance. The sen- order to become ionized. However, any gases or vapors sitivity of a photoionization detection system is propor- in the air stream which have ionization energy levels tional to the efficiency with which ultraviolet radiation below that generated by the lamp, are ionized. Included can cause ionization. Careful detector design is a key in this latter group are the vast majority of those com- factor in PID direct reading instrument performance. pounds which we describe as "pollutants". Thus, T/P' "picks out" the pollutants and ignores the clean air, and • T/P"s photoionization detector is exclusive to Photovac. this is the essence of the principle used. The electric A carefully selected lamp energy results in a PID of current due to the ion formation and collection is striking sensitivity. The design simplicity not only amplified and can be used in a number of ways to ex- press "Total lonizabies Present".