Spectrophotometer

Administrative Officer

Charlotta Andersson

Institution / equivalent

Department of Biochemistry and Biophysics

Inquiry

About Stockholm University

Stockholm University is characterized by openness and an innovative and cross-border activity in Sweden´s capital. Ranked as one of the world´s top 100 HEIs, Stockholm University is one of Europe´s leading institutions for higher education and research in human sciences and natural sciences.

Stockholm University was founded in 1878 with the ambition to renew the traditional universities in Sweden. Close contacts and an active exchange of experience and knowledge with the outside world characterize the business since its inception.

33,000 students, 1,600 doctoral students and 5,500 employees are active at Stockholm University. Within the science areas of science and human sciences, 190 study programs and 1,700 courses are offered. The university has a total turnover of SEK 4.93 billion.

Stockholm University contributes to knowledge development in a global perspective and in collaboration with others. This is done through education and research in the international front line, as well as in cross-border and multidisciplinary studies. In collaboration with the surrounding society, knowledge is made available to everyone through dialogue and participation in debate and social development.

1 About the contracting institution

The Department of Biochemistry and Biophysics is composed of more than 30 active research groups that span across a broad range of topics covering various aspects of structure and function in biological systems. The combination of the highly interdisciplinary expertise and research projects at the Departments is unique in Sweden and also at an international level. This expertise ranges across cell biology, biochemistry, biophysics and theory with the majority of these disciplines centered on biological membranes. Specific research topics include: membrane protein biogenesis, topology and assembly; mitochondria and chloroplasts; protein structure, function, and disease; protein folding and trafficking; lipid biosynthesis and function; energy conversion and biological nitrogen fixation; DNA-RNA-PNA interactions; bioinformatics; and computational structural biology, biochemistry, and development of theoretical tools.

The experimental studies are performed in different organisms and combine a wide range of advanced biochemical and biophysical techniques.

2 Goals and purpose

We are looking to purchase a flexible spectrophotometer system to collect highly time-resolved absorbance and fluorescence spectra. This machine is used to follow the change in concentration of various biomolecules that have absorbance of fluorescence properties. These techniques are central to all of the experimental projects being carried out in the laboratory making this a key piece of equipment.

3 Requirement specification

Spectrometer system (product) requirements:

The product must have the ability to hold standard (45x12.5x12.5 mm) cuvettes made of plastic or glass in a temperature-controlled holder allowing measurements from 4-95°C with an accuracy of ±0.2°C or better (variance of the actual cuvette holder temperature vs the temperature controller target temperature) and precision of ±0.1°C or better (the fluctuation in temperature controller temperature while being held constant). If a water recirculation bath is required for cooling a the temperature regulation device (e.g. Peltier) temperature regulation, it must NOT be included in the tender submission as we already have this equipment in the lab.

The product must have a wavelength range of at least 200-850 nm with an optical resolution of >1.5 nm. The product must be able to collect absorbance or fluorescence spectra across a range of >600 nm at a speed of >1000 spectra/s (i.e. allowing millisecond-resolution) in a time-based (kinetics) experiment. The system must have a signal-to-noise of at least 250:1 and a dynamic range of >5000:1. There must be an ability to change the slit width at the spectrometer either through the software, manual adjustment or using user-changeable parts.

The product must include two (2) polarization filters mountable on the excitation and emission path and software controls that enable the measurement of fluorescence polarization (fluorescence anisotropy).

The product must be upgradable to carry-out kinetic absorbance and fluorescence measurements simultaneously and be configurable for the addition of external triggers such as for the addition of an after-market stopped-flow apparatus.

Apart from the specifications listed above, the product must be able to carry out this specific complex kinetic experiment: measure in rapid succession (<1 s separation) the absorption spectra between 200-600 nm as well as the fluorescence emission at 510 nm resulting from excitation at 404 and 454 nm. The result is three (3) data points collected within 1 s of each other: [1] an absorption spectrum, [2] Ex404/Em510, [3] Ex454/Em510. These measurements must be able to be collected every second for at least 2 h. This will allow us to characterize the kinetics of the activity of the enzyme NADH:quinone oxidoreductase I, which oxidizes NADH and reduces quinone to create a proton gradient across a membrane bilayer. Therefore, we measure: the concentration of NADH (A320) the concentration of quinone (A220/A278), and the pH via the dual-excitation ratiometric dye pyranine (8-hydroxypyrene-1,3,6-trisulfonate (HTPS)) over time.

The product, in its largest configuration (i.e. simultaneous absorbance and fluorescence measurements) must not exceed a benchtop footprint of 120 cm x 70 cm not including any auxiliary (i.e. the PC or the water bath). If any additional infrastructure for mounting the instrument beyond a standard bench and is not included with the product quote (e.g. optical breadboard) this must be stated in the tender submission.

The product must be compatible with consumables and reagents from many suppliers without affecting the warranty and must NOT rely on proprietary reagents or consumables.

Instrument control software and hardware, sufficient to operate the full capability of the instrument and export data for further analyses must be included in the tender submission. If a PC is required to control the product via the provided software, connection must be USB or the manufacturer must provide a suitable PCI board and cable with the product. Software must be compatible with either Windows 10 Enterprise or Linux and able to export data in ASCII text format (e.g. csv) readable by different analysis software. The software must be supported with security updates and bug fixes as required for the duration of the warranty/service contract of the product.

The product should be available for delivery as soon as possible and no more than two months from the order date.

The product must have a warranty of 2 years that covers repair or replacement of the spectrometer(s), light source, and temperature-controlled cuvette holder. The spectrometer(s) must be covered by a 5-year service contract, which includes all manufacturer recommended maintenance and calibration that cannot be carried out by the user. The service contract can be billed per year, but the pricing should be fixed for the duration of the 5-year period and the total cost included itemised in the quote. A comprehensive document detailing what is covered by the warranty and service contract must be included with the tender submission.

The product must have mainline repair support (i.e. spare parts for the product must be available) for a minimum of 5 years from the date of purchase. Responses to technical enquiries by email must take no more than 5 working days.

The product must be CE-marked (includes environmental requirements and constitutes standard)

4 Quotation

When deciding on the product, all the requirements must be satisfied in full, and the most affordable product will be selected.

We expect quotation regarding the above and wish the following to be stated in the quotation;

Price (state the total price for delivery including the warranty and service contract)

No other costs may be added for the commission´s implementation.

Answer specifically in the tender how the offered product meets the required specifications. Ideally, this should be carried out point by point for clarity. Supporting technical documents indicating how the specifications are met should be included in the tender submission where appropriate.

The quotation will be submitted no later than 2022-04-30

The quotation must be binding with 2022-07-30

5 Evaluation and award (supplier selection)

The supplier offering the most advantageous solution to the contract is awarded the contract. SU evaluates the tenders in accordance with the above requirements.