Page 93 -

Page 93 Jenway Catalogue
When sodium is introduced into a flame, it emits a radiation in the yellow region of the visible spectrum. The table
below gives details of the measurable atomic flame emissions of the alkali and alkaline earth metals in terms of the
emission wavelength and the colour produced.
Element Emission Wavelength (nm) Flame Colour
Barium (Ba) 554 Lime Green
Calcium (Ca) 622* Orange
Lithium (Li) 670 Red
Potassium (K) 766 Violet
Sodium (Na) 589 Yellow
*Note: Calcium is measured by using the calcium hydroxide band emission
at 622nm as the calcium main atomic emission occurs at 423nm.
Flame Photometry: Wavelengths of Elements
Spectrophotometric conversions
Some analyses such as enzyme kinetics require the absorbance change to be measured over time and often require
the sample’s temperature to be controlled electrically (peltier control) or by circulating water through the sample
holder. Temperature control options are available for all Jenway spectrophotometers.
Different measurements can require a differing degree of post-scan data
manipulation. Jenway spectrophotometers offer a wide-range of post
scan manipulation options and all can be connected to a PC.
A260 = 1 (1cm detection path) Concentration (μg/ml water)
dsDNA 50
ssDNA 33
ssRNA 40
Oligonucleotide 20 - 30
Pure DNA has an A260/A280 ratio of 1.8-2.0 in 10mM Tris-Cl, pH 8.5
Pure RNA has an A260/A280 ratio of 1.9-2.1 in 10mM Tris-Cl, pH 7.5
Selecting a Spectrophotometer
Spectrophotometric Quantitation of Nucleic Acids
Is sample temperature control required?
Spectrophotometric conversions
Does the spectrophotometer need to be connected to a PC?
Jenway Catalogue