Vol. 97/2 No. 1 September 1997

A Breakthrough in Flame Photometry!

Flame photometry remains the preferred method of analysing alkali elements. As its use was to a great extent restricted to clinical applications, no great effort was put into developing modern and more performing instruments. Thus for about 30 years there was little change in flame photometer design. Although these instruments gave useful information, they needed complex sample preparations, frequent instrument manipulations and the whole analysis routine took considerable time.

High Performance Flame Photometry (HPFP)Τ was developed by Advanced Technical Services GmbH, Switzerland. It is a new and proprietary technology that allows to overcome most of the shortcomings of earlier instruments and is thus of great benefit to all laboratories that need to use flame photometers.

For a short comparison let us consider first some of the problematic features of traditional flame photometers.

Outside of the clinical range, conventional flame photometers do not give analytical results in direct concentrations and not over a wide linear range. They require at least 2 standard values (often 4 or more standards), a lower and a higher to the expected concentration value of the sample but they cannot read from zero to the high point in a straight line; at 3 ppm they are already off by 2%.

The photometric analytical response curve for Sodium (Na) for instance starts from a zero origin, then has a very small straight linear segment near the zero point, before bending into a curve. This results in a deviation of 1.5% from the linearity in the concentration range of 0 to 3 ppm at 1.5 ppm! Therefore sample dilutions are necessary for which standards have to be prepared. Outside this range, the data is each time plotted on a linear paper, giving at the end the concentration of the element in the sample. Though in the recent past many flame photometers were outfitted with a digital readout, frequently the operation procedure remains the same, i.e. that of an analog response: the analysis values on the digital readout of the different sample dilutions are recorded on a graph paper. The opposite routine is used when unknown samples are analysed.

The signal reaction of older instruments is also slow and unstable, needing constant rescaling. Furthermore the signal is drifting, making it necessary to continuously correct for the zero with distilled water and the slope with the high standard(s). These constant adjustments require much time, not to mention the high cost for analytical reagents and personnel time.

The ATS HPFPΤ technology has simplified the analysis procedure and eliminated most of the costly and tedious work outlined above.

The ATS High Performance Flame Photometers (HPFP)Τ, are designed to have high sensitivity and to measure over much wider concentration ranges. Thanks to their unique extended straight segment linearity fewer or no dilutions of the sample are needed and the analysis result can generally be read in direct concentrations. This reduces the complexity of sample preparation and eliminates the need of plotting on a graph paper and thus transcription errors. Click here to look at data.

The ATS High Performance Flame Photometers (HPFP)Τ, require only one high standard and the blank to set the zero instead of the usual multiple standards. They have a reliable zeroing that needs not be checked over 5, 10, 20 or more samples. The same applies for the "high standard" for slope calibration: the need for frequent rescaling is eliminated.

The ATS 200 (HPFP)Τ Series Analysers are very steady, fast and give repeatable readings for 30 or more tests! Measurements can be done at a 6 seconds fixed integration cycle with repeatable values displayed; no more guesswork! But most important is their greatly increased analytical accuracy and precision.

The instruments can be interfaced with a PC Data Station that extends their potential even further and permits GLP and method validation to be introduced in the laboratory. It also eliminates the need to manually record results.

In conclusion, the ATS 200 (HPFP)Τ System offers increased productivity, superior analysis quality, and considerable yearly savings of manpower time and consumables. It allows even extensive projects where a great number of analyses have to be done in a relatively short time (for instance the health screening of the population of a whole area) to be implemented readily.