J-1100 Circular Dichroism Spectrophotometer

System Description

The J-1100 uses simple optimised parameters so that a wide range of users with different levels of CD knowledge can get right down to work and successfully obtain high-quality data. The wavelength range from 180 to 600 nm is suitable for obtaining secondary and tertiary structure measurements in the near- and far- UV. When fitted with a Peltier cell holder, the J-1100 can be used for measurement of CD, LD and absorbance as a function of wavelength, temperature and time.

The intuitive Spectra Manager™ Suite of spectroscopy software provides the user with sample measurement, independent from the data processing and analysis. This allows users to obtain new measurements while simultaneously analysing previously acquired data for increased productivity.

Advanced Features

• High optical throughput
• Double prism monochromator providing low stray light
• Wide dynamic range PMT detector
• Highly efficient nitrogen purge system
• Digital signal processing
• Simultaneous Multi-Probe: CD, LD, HT, DC, absorbance, fluorescence

Unique Benefits and Accessories

• Compact benchtop design
• Range of precise temperature control accessories
• High-throughput automated CD
• Automated titration and stopped-flow
• Spectra Manager™ software for control and extensive data analysis
• Flexible design allows field upgrades for different measurement capabilities as applications and budgets evolve

Enhanced vacuum-UV measurement

The innovative optical system of the J-1500 permits the measurement of a CD spectrum in the vacuum-UV region down to 163 nm. The enhanced light throughput and new digital lock-in technology now allow for a small signal in a very noisy environment to be detected. Additionally, the optimisation of the nitrogen purge efficiency helps to reduce the amount of oxygen in the optical bench so that it does not bury the sample signal.

These features ensure that CD spectra can be obtained from strongly absorbing and high signal-to-noise (S/N) samples across the spectrum and into the vacuum-UV region. The quality of spectral data obtained, including data obtained at shorter wavelengths, substantially improves the accuracy of protein secondary structure analysis.

High Sensitivity and Wide Dynamic Range of PMT Detector

The PMT detectors used in the JASCO system are specially selected for the highest sensitivity and lowest birefringence. The wide dynamic range of the PMT detector ensures that large variations in signal intensity can still be detected, even for highly absorbing samples. The result is superior linearity between concentration and absorbance compared to other types of detectors including solid-state APD and CCD detectors.

The gain on a PMT detector is much larger (107) than most detectors, and therefore, the signal amplification is larger. Under conditions with adequate light intensity, this typically leads to a larger amount of noise and therefore a lower S/N ratio. However, under conditions where there is a small amount of light hitting the detector (i.e. far-UV region), the gain of the PMT allows for good signal amplification at very low noise, increasing the S/N ratio.

Exceptional stray-light rejection

The double polarizing prism monochromators of the J-1000 series result in stray light lower than 0.0003%, enabling the instruments to obtain high-quality CD data even under conditions with high absorbances.

Simultaneous Multi-Probe Measurements

The latest quad-channel lock-in amplifier provides simultaneous acquisition of up to four data channels, including CD, HT, DC, absorbance, linear dichroism (LD), fluorescence, fluorescence-detected CD (FDCD), fluorescence-detected LD (FDLD) and fluorescence anisotropy.

Additionally, the lock-in amplifier obtains a signal at a specific resonance frequency while filtering out noise signals at other frequencies, helping to provide spectra with excellent signal-to-noise ratios.

Rapid Scanning

High sensitivity combined with a 10,000 nm-per-minute maximum scan speed allows the J-1500 to measure samples quickly, increasing productivity in your lab. An additional benefit is the minimal time exposure of biological samples to the high-energy UV light, minimizing the risk of sample degradation. A mechanical shutter can also be programmed to open and close only during actual measurement to further avoid UV exposure.

Highest S/N Performance

The high S/N (signal-to-noise) performance of the J-1000 series is achieved by a high-throughput optical system and low-noise signal processing. RMS Noise < 0.004 mdeg (185 nm) for the J-1500 and J-1700, < 0.03 mdeg (200 nm) for J-1100.