Supplementary data: High sensitivity micro-volume UV absorption spectrometry for routine analysis of small volume biological samples

Supplementary Table S1. Comparison of sample volume,
path length, and detection limit among commercial nano- or micro-volume
absorption spectrometers and apparatus. Data in the table were obtained from manufacturers’
webpages (refer to the references indicated in the table). The results of this
work are listed at the bottom line for comparison.
Supplementary Table S2. Information on the internal
volumes of micro-tubes with various combinations of internals dimeters and
lengths.
Supplementary Figure S1. Schematic of the fluidic
control body to be assembled with the spacer defining the internal fluidic
channel. The fluidic control body also provides receptacles for an absorption
cell as well as an optical fiber fetch cable to optically couple them
together.
Supplementary Figure S2. The detailed presentation
of the interfacing area of the fluidic control body.
Supplementary Figure S3. Schematic of the light
passage for absorption measurement (not to scale): (a) light source, (b)
optical fiber, (c) fiber receptacle, (d) window, (e) absorption cell, (f)
detection well, (g) spectrophotometer module or photodiode.
Supplementary Figure S4. Graphical presentation of
the prototype instrument equipped with the proposed absorption cell as well
as the disk type sample tray.

Supplementary
Figure S5. Gradual change in the effective path length of the proposed
absorption cell created from absorption curves of a diluted phenolphthalein
indicator obtained with the proposed absorption cell and a conventional
absorption cell (path length 10 mm) made of quartz. The middle region of
wavelength giving poor signal to noise was omitted from plotting to avoid
misleading by unreliable data points.
Supplementary Figure S6. Linear relationship
between the assigned absorbance and the measured absorbance for the
gravimetrically diluted NIST SRM935a at 257 nm. The R²value of
linear fitting was 0.9997 whereas the slope was 0.992 for the standard
solutions of absorbance 0.011 – 2.56.