5
Light Detector
Silicon Photocell
Environment
0 to 50°C (32 to 122°F); max 95% RH non-condensing
Battery Type
4 x 1,5 volt AA batteries / 12 to 20 VDC through voltage adapter
Auto-Shut off
After 15' of non-use.
Dimensions
225 x 85 x 80 mm (8.7 x 3.3 x 3.1")
Weight
500 g (17,6 oz.).
SPECIFICATIONS
Precision is how closely repeated measurements agree
with each other. Precision is usually expressed as
standard deviation (SD). Accuracy is defined as the
nearness of a test result to the true value.
Although good precision suggests good accuracy,
precise results can be inaccurate. The figure explains
these definitions.
For example for phenols: in a laboratory using a
standard solution of 0.350 g/L gallic acid and a
representative lot of reagent, an operator obtained
with a single instrument a standard deviation of
0.015 g/L.
PRECISION AND ACCURACY
The reaction between phenols and the Folin-Ciocalteu reagent involves oxidation of the phenolic groups (R-
OH) with a mixture of phosphotungstenic acid (H
3
PW
12
O
40
) and phosphomolybdenic acid (H
3
PMo
12
O
40
) to
the quinoid form (R=O). The concomitant reduction of the Folin-Ciocalteu reagent causes a blue color in
the sample that is proportional to the total phenolic content that, in turn, is expressed as g/L of Gallic Acid
Equivalents (GAE).
Another common method to express the phenol content is to report the Folin Index (FI) or Total Phenol
Index. Simply multiply the read value in g/L of GAE times 25, to find the Folin Index value.
24
• Add 6 drops of HI 83742B-0 Folin & Ciocalteu’s
Reagent to the cuvet.
• Replace the cap and shake gently to mix.
x 6
#2
(Sample)
• Use the 200 µL automatic pipette with a clean
pipette tip to add exactly 0,2 mL of
diluted red
wine sample
.
10 mL
• Wait for 1 minute and then use the 3 mL pipette to
add HI 83742C-0 Reagent C Carbonate Buffer, to
bring the volume up to the 10 mL mark.
• Turn the meter ON and press RANGE to select the
parameter code “P5” for total phenols, red wine (see
page 13). Then hold down READ/TIMER for several
seconds. The instrument will show the countdown.
Alternatively, wait for 2 hours.
The instrument gives an acoustic signal to alert the
user that the countdown is finished.
• This is the reacted sample.