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NIR & UV–VIS LABORATORY SAMPLING ACCESSORIES
Axiom Analytical offers a broad line of fiber–optic coupled sampling equipment for use 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. LABORATORY NIR & UV–VIS LIQUID TRANSMISSION
Axiom Analytical offers a complete line of near–IR and UV–visible liquid sampling accessories. Those listed below are especially geared to the needs of laboratory analysis. Other products can be found in the Process–Line section of this website.
1. FST–500 Variable Path Sampling Stage…beyond the cuvette sampler.
Ideal for rapid sample survey and applications development.
The one sampling device every lab should own! The FST–500 provides highly flexible sampling of liquids contained in cuvettes or plastic bags—and even pliable solids. Traditional cuvette samplers provide only one fixed pathlength, determined by the dimensions of the cuvette. With the FST–500, you can vary the pathlength from 0 to 6 cm, enabling you to survey diverse samples and determine the optimum pathlength and spectral region for subsequent dedicated analyses. Samples are positioned between a movable probe and fixed optics mounted in the sampling stage. For liquid sampling, the probe is most often dipped into a clear bottomed cuvette (provided). The position of the probe—and hence the pathlength—is measured electronically and read out on a digital display.
FST–500
- Pathlength manually adjustable from 0 to 6 cm
- Electronic pathlength readout resolution 0.01 mm
- Fluid sampling using a clear bottomed cuvette or plastic bag
- Compatible with single fibers or bundles
2. Single Pass Transmission Probes
Axiom's single pass transmission probes set the standard for robustness and photometric accuracy. Both the FPT–720 laboratory probe and FPT–850 process probe employ a single pass through the sample thus eliminating stray light and maximizing the sample gap for a given transmission pathlength. In addition, Axiom’s patented optical design eliminates the need for optical fibers within the probe, eliminating fringing effects and providing a high degree of stability over a wide range of temperatures and pressures.1, 2
FPT–720
- User interchangeable pathlengths
- Redundant Kalrez®/PTFE seals
- High photometric accuracy
- Freedom from stray light and fringing
- Pathlengths from 1 mm to 20 cm
3. Transflectance Probes
Transflectance probes employ two passes through the sample. This makes possible a substantially smaller diameter than is practical with single pass probes. Axiom’s FPX Series Transflectance Probes employ the Company’s patented welded window seal design3, making these probes suitable for use at high temperatures and pressures and with virtually any chemical system.
FPX SERIES
- 1/4” diameter for small scale reaction monitoring
- Withstands highly aggressive chemicals
- High temperature and pressure operation
- Can be multiplexed
4. Variable and Fixed Path Flow Cells
xiom’s FFV Series fiber–optic coupled liquid flow cells offer the choice of either variable or fixed pathlengths, with standard pathlengths ranging up to 20 cm. The use of 316 stainless steel construction with sapphire windows and Kalrez seals makes these cells suitable for a wide of range chemical systems. Alternative materials of construction, such as Hastelloy C–276 and Kaynar, are also available.
FFV SERIES
- Variable or factory–set pathlengths
- Pathlengths from 0.5 to 20 cm
- Unrestricted flow path
- Robust stainless steel/ sapphire/ Kalrez® construction
B. LABORATORY NIR & UV–VIS GAS TRANSMISSION
Traditionally, near infrared spectroscopy has 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 gas analysis in the laboratory.
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
2. Multipass Gas Cells
FFM Series cells4 were designed primarily to meet the rigorous requirements of process gas analysis.However, they offer unique benefits for laboratory analysis as well.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
C. LABORATORY 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-922.5, 6, 7
1. Immersion Probes
FDR–700 Series probes3,8 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
2. Non–Contact Probes
FDR–800 Series probes4are 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 inthe 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)
D. LABORATORY 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.9
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
REFERENCES
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