Powerful control at your fingertips

A (very) short history of spectroscopy

First there was the conventional mechanical scanning spectrophotometer, introduced forty-odd years ago. Beyond some refinements, it has remained basically unchanged since its introduction.

Then there was the diode array spectrophotometer, invented by HP to overcome some of the shortcomings of its mechanical cousin. Introduced in the 1970's, the diode array spectrophotometer offered speed, reliability, reproducibility and far easier operation.

This performance was unapproachable by ordinary spectrophotometers. Unfortunately, these advantages were initially offset by a few technical teething-problems (slightly lower resolution, susceptibility to stray light), and a price premium associated with the technology.

HP 8453E — performance and simplicity at an affordable price

In 1995, with the introduction of the HP 8453, diode array technology become the equal of — or superior to — mechanical scanning spectroscopy in all the performance aspects that mattered. In addition, it had now arrived at the same price range as other PC-controlled spectrophotometers.

Still, for many customers  the PC's ability to compile the resulting data, archive it, analyze it, network it, multitask with other applications, and implement good laboratory practices were powerful advantages. Nevertheless, a significant number of potential users failed to understand why anyone would want to pay for a whole PC system to control something as simple to use as a spectrophotometer.  In fact, neither could HP.

"We wanted to make a version of the HP 8453 which would be less expensive," says HP Product Marketing Manager Tony Owen, "and we wanted a user interface which was much simpler and easier to use."

So HP set about to find a way to eliminate the PC as a spectrophotometer faceplate.

The controller breakthrough

For some time now, HP has been using its highly regarded palm-top technology to control the HP 1100 Series liquid chromatograph. This has proved immensely popular with the LC set. The handheld controller looks like a computer game. People can't resist it. Why not try it out as a spectrophotometer controller?

Once again, it proved to be remarkably successful. People immediately wanted to pick it up and use it. Unlike the PC interface, which some users found intimidating, the palm-top controller was actually inviting to use.

The handheld controller redefines the standard for ease of use

Its interface couldn't be simpler — eight softkeys arranged around the display for setting up and taking measurements, a number pad, four navigation buttons, and a function key for expanded capabilities. Also an online help button. The controller attaches to the instrument with a coiled cable not unlike a telephone handset cord.

The result, which is called the HP 8453E, is an instrument that any user could love. In particular, users in such areas as education will find it particularly appealing. It is fast, rugged and reliable. It is especially easy to use for fixed wavelength or multiple wavelength measurements, spectrum measurements, quantification. Because it is a diode array, if you ask it to do a measurement at 400 nm, it will show you the absorbance value at 400 nm, but then if you then press the Graphic button, you will see the entire spectrum. All the data is available with the first measurement.

It is also good at kinetics, doing enzyme analyses for blood and other organic mixtures. Everything needed to make these measurements is contained in the standard product.

And there's a bonus. Through the keypad, you can enter your own equation for evaluation of the results, thereby adding a level of flexibility unmatched by other instruments in its class.

Finally, the controller interface is plug-compatible with a PC. If you want to switch to PC control to get the additional capabilities it affords, just disconnect the palm-top and plug in the computer.

So the handheld controller is a hit, the second best thing to happen to spectroscopy since the diode array.

The best thing

Single-beam optics and open sample area — just two of the many diode-array advantages

Better than thirty percent lower than the cost of a PC-controlled HP 8453, for the entire spectrophotometer bundle, including the basic instrument, the hand-held controller with software preloaded, and an HP Deskjet printer.

"We have accomplished this price reduction with no loss of quality anywhere in the product," says Tony Owen. "We have done it primarily through leveraging our technology platform and through manufacturing efficiencies."

For example, converting palm-top technology from LC to spectroscopy use was merely a matter of software development. In addition, HP was able to leverage the development and manufacturing costs of the diode array, which is quite similar to the detector the company supplies with its liquid chromatograph.

The result: "As far as I know this is the lowest cost diode array spectrophotometer that's ever been available," Tony notes. And, he adds, "it's also the best diode array spectrophotometer that's ever been available, from HP or anyone else."