AXIOM PROCESS–LINE

NIR & UV–VIS

NIR & UV–VIS PROCESS SAMPLING EQUIPMENT

Axiom Analytical’s line of fiber–optic coupled sampling equipment has established an unparalleled record of robust reliability in on–line process analysis. A significant factor in making this possible is the use of the Company’s patented welded nickel–alloy seals.¹ These are the only window seals capable of providing reliable long–term operation under conditions of high pressure, high temperatures, temperature cycling, and/or highly aggressive chemistries.

Axiom’s fiber–optic coupled sampling equipment can be used with all near–IR and UV–Visible spectrometers. A summary of product lines is provided below. To jump to specific sections of the list, click on the following categories:

A. LIQUID TRANSMISSION
B. GAS TRANSMISSION
C. DIFFUSE REFLECTANCE
D. ATR CHROMOPHORE ANALYSIS
E. FIBER-OPTIC MULTIPLEXERS AND INTERFACES

A. PROCESS NIR & UV–VIS LIQUID TRANSMISSION

Axiom Analytical offers a complete line of near–IR liquid sampling equipment. Those listed below are especially geared to the needs of process analysis. Other products are to be found in the Lab-Line section of this website.

1. Single Pass Transmission Probes
2. Cross Line Sampling Systems
2. Liquid Flow Cells

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1. Single Pass Transmission Probes

The introduction of the FPT–850^{1, 2} in the late 1990’s was a revolutionary event in the history of near infrared process analysis. By eliminating the failure modes that had plagued previous fiber–optic coupled probes, the FPT–850 has made highly reliable in–line process analysis a practical reality.^{3, 4} With the FPT–850, near–IR sampling can now be performed directly in a process line or vessel, eliminating the need for expensive and trouble–prone sample conditioning systems.⁵ The significance of this development is attested to by the fact that several hundred FPT–850’s have now been installed and are operating continuously at plants throughout the world.

FPT–850 PROCESS PROBE

Welded metal seals for extreme robustness and chemical resistance¹
Withstands temperature cycling and thermal shock
NEMA–4 classification standard
Freedom from stray light and fringing
Standard pressure ratings to 250 bar
Temperature ratings to 400^o C

View Data Sheet (.pdf)

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2. Cross–Line Sampling Systems

FCT Series sampling systems offer many of the benefits to the FPT–850 probes but in a form suitable for sampling across a flow path. They are especially suited for use with highly viscous samples such as polymer melts.⁶ They can be mounted at the output of a small extruder or in a rheometer loop on a large process extruder.

FCT SERIES

For polymer melts and other demanding process applications
Welded metal seals for extreme robustness and chemical resistance¹
Compatible with high temperature/pressure/viscosity
Minimum possible flow restriction
Customized flow fixtures to meet individual needs

View Data Sheet (.pdf)

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3. Liquid Flow Cells

FFV Series transmission cells are designed to provide uncompromising performance for a wide variety of process development and on–line process applications. They combine high optical transmission with an unimpeded flow path and a wide range of available pathlengths—which can be either factory set or user adjustable. These capabilities are made possible by the use of a pair of precisely engineered optical plungers which face each other across the flow path. These are mounted on a choice of four different cell bodies, providing features such as pathlengths ranging form 0.5 mm to 20 cm, flow diameters to 25 mm, temperature control capability, a cleanout port, and a ninety degree scattered light port. Each of the models is available in versions optimized for near–IR, visible, or UV operation.

FFV SERIES

Variable or factory–set pathlengths
Pathlengths from 0.5 to 20 cm
Unrestricted flow path
Robust stainless steel/ sapphire/ Kalrez® construction

View Data Sheet (.pdf)

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B. PROCESS NIR & UV–VIS GAS TRANSMISSION

Traditionally, near–IR or UV–Visible spectroscopy have not been widely used for gas analysis due to low sample density and the relative weakness of the overtone bands. However, this situation has changed dramatically with the advent of highly sensitive spectrometers such as those based on tunable diode lasers. This development provides two important benefits—a very significant increase in source brightness and the potential for high resolution. The latter benefit greatly enhances specificity and sensitivity by enabling the resolution of individual rotational bands.

Axiom offers two fiber–optic coupled product lines specifically tailored for near–IR or UV–Visible gas analysis.

1. Low Volume Gas Cells
2. Multipass Gas Cells

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1. Low Volume Gas Cells

FFT Series Gas Cells employ a folded–path design utilizing small diameter gold–coated lightguides. This design provides extremely low volume and rapid sample exchange. In addition, the precise overlap of the gas flow and optical paths insures a very high degree of stability and photometric accuracy. These cells are available in pathlengths to two meters.

FFT SERIES

Low Volume
Fast response
Negligible sample carryover
Fixed, unambiguous pathlength
Easy maintenance

View Data Sheet (.pdf)

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2. Multipass Gas Cells

FFM Series cells⁷ were designed primarily to meet the rigorous requirements of process gas analysis. These cells take advantage of the spatial coherence characteristic of the new generation of spectrometers based on tunable lasers to provide multiple pass operation combined with ease of alignment. In addition, the mirror coatings are on the outside of fused silica windows, making it possible to completely clean out the cell without risking damage to the optics.

FFM SERIES

Low Volume
Fast response
Negligible sample carryover
Fixed, unambiguous pathlength
Easy maintenance

View Data Sheet (.pdf)

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C. PROCESS NIR & UV–VIS DIFFUSE REFLECTANCE

Near–IR has been used for the analysis of agricultural products and other scattering solids for many decades. In the past, most applications have involved either loading the product onto a specialized sampling stage or the use of probes based on large diameter fiber–optic bundles. In contrast, Axiom’s diffuse reflectance probes are designed to be used with small diameter bundles or even single fibers. This provides greater flexibility, much lower transmission cost, and optimum coupling to the newer generations of spectrometers such as those employing charged–coupled detector arrays, FT–NIR, and tunable laser diodes. For further discussions of diffuse reflectance analysis, see Technical Notes AN–911,AN–916, and AN-922.^{8, 9, 10}

1. Immersion Probes
2. Non–Contact Probes

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1. Immersion Probes

FDR–700 Series probes^{1, 11} are designed for insertion into a scattering sample such as a powder or slurry. These probes employ detachable bifurcated single fibers or small fiber bundles for economy and convenience. Individual models are optimized for applications ranging from hand-held sample survey to polymer melt analysis.

FDR–700 SERIES

Both lab and process versions available
Compatible with single fibers and small bundles
Suitable for immersion in aggressive chemicals
Compatible with high temperatures and pressures
Large depths of field
Purely passive and non–hazardous

View Data Sheet (.pdf)

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2. Non–Contact Probes

FDR–800 Series probes⁷ are designed for use with a finite sample offset. The proprietary design of these probes allows a sample to be viewed through a thick window without incurring stray light due to window reflection. Their compact structure and passive nature makes them ideal for both laboratory and process sampling in the pharmaceutical industry.

FDR–800 SERIES

Target offsets of typically 12 – 15 mm
Immune to reflection from window surfaces
Viewed spot diameters of typically 8 mm
Purely passive (employs separate optical source)
Large depth of field
Convenient form factor (2.5 cm diameter x 10 cm long)

View Data Sheet (.pdf)

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D. PROCESS UV–VIS ATR CHROMOPHORE ANALYSIS

Many dyes, aromatics, and other chromophores have absorptions in the UV and visible regions of the spectrum that are orders of magnitude too strong to allow transmission analysis without substantial dilution. However, these substances can often be analyzed by means of attenuated total reflectance (ATR). Axiom’s FNL Series ATR cells⁴ provide a high degree of flexibility by allowing the characteristics of the ATR element to be specified for optimum performance in a given application.¹²

FNL SERIES

Fiber–optic coupling to most UV–Visible spectrometers
Response down to 200 nm
Sensitivity set by interchangeable ATR elements
Compatible with lab and process applications
Rapid sample cleanout

View Data Sheet (.pdf)

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E. PROCESS NIR & UV–VIS FIBER-OPTIC MULTIPLEXERS AND INTERFACES

FMX Series multiplexers^{13, 14} allow a single spectroscopic instrument to be switched between multiple sampling devices. Both mono– and bi–directional models are available. In addition, fiber–optic interfaces are available for use with instruments not already equipped with fiber–optic connections.