The BioSpec-mini UV-Visible Spectrophotometer from Shimadzu is designed to meet the everyday needs of a molecular biology laboratory. This spectrophotometer is designed to measure and analyze nucleic acid and protein samples, as well as provide spectrum data and bacterial cell count measurements.
The unit is compact and requires little bench space, with a footprint of only 600 mm x 480 mm (WxD). A large backlit LCD panel is used to display the menus and results, and the contrast can be adjusted to suit lighting conditions as required. The sample compartment is accessed by a door that hinges up. The sample compartment can be configured to take a single or a multi-cell holder for multiple samples. The BioSpec-mini can take disposable cuvettes as well as capillary cells, 5 and 100 µl cells. The keyboard is made from a single molded plastic sheet, which makes it ideal for a laboratory environment where moisture and powder from gloves can cause problems with electrical appliances. The keyboard has both a numerical keypad as well as keys to start and stop measurements, zero samples, change the wavelength, alter the LCD screen contrast and print your results (printer not supplied). The unit has a slot for an IC card and a port for connecting a computer or printer if desired. In addition, there are connections for a number of Shimadzu accessories including an Auto Sample Changer and pumps to aspirate a sample into a flow cell.
There are five modes of operation available – Nucleic Acid Analysis Mode, Protein Analysis Mode, Spectrum Mode, Cell Count Measurement Mode and Tm Prediction Mode. The menus for each section are easy to operate. A feature of the BioSpec-mini is that for each mode, programs are available for detailed analysis of measurements. For example, in Nucleic Acid Mode, rather than simply calculate the absorbance of your sample at one wavelength, if you provide the pathlength and dilution factor, the spectrophotometer will quantify and check the purity of a sample by measuring more than one wavelength simultaneously. In addition, if you enter the base composition of an oligonucleotide, the spectrophotometer can calculate the molecular weight and molar absorption coefficient. Similar analyses can be performed in the other modes, including four different methods of protein quantification (Lowry, BCA, CBB and Biuret Methods) and the ability to create calibration curves.
We have used the BioSpec-mini in our laboratory for 2 years, and have found it a robust and reliable piece of equipment. It should be noted that it takes approximately 5 minutes to warm up and initialize, which can be frustrating if waiting for an important result. The manual supplied with the machine is detailed, and includes information on troubleshooting results and maintenance of the instrument. It is possible that this spectrophotometer may be over-qualified for some laboratories, as we have not yet used all of the various functions.
Research Scholar
School of Molecular and Microbial Sciences
The University of Queensland