HF scientific DRT-100B Research Turbidimeters - Manual (Page 13)

Page 5 DRT-100B (5/00)
(B) STANDARDIZATION (cont’d)
The instrument is now referenced to the factory calibration and unknown samples may be read directly in NTU.
For best accuracy, the instrument should be standardized on a scheduled basis. The need to actually adjust
standardization will vary depending upon the operational environment.
(C) SAMPLE MEASUREMENT
1. Place the sample in the Optical Well.
2. Set the Range Switch located on the front panel to an appropriate range.
3. Read the value on the digital display.
For accurate measurements in the low range rotate “grab samples” cuvettes in the well to obtain the minimum
reading. Mark the cuvette and the instrument so that orientation of the cuvette will be identical each time it is
placed in the instrument. Always use the cuvette cap when measuring a grab sample.
NOTE:
1. Settling particles or air in the sample may cause the digital reading to change rapidly. Readings should
be taken without delay before turbid particles settle.
2. Cuvettes must be clean and free of smudges or scratches. Cleaning is accomplished by washing in a
detergent solution then rinsing thoroughly 8 to 10 rinses in clean, preferably distilled, water to remove
all streaks.
Scratched cuvettes should be replaced.
Reusable cuvettes, (pkg. of 10 each - catalog number 50052, pkg of 3 - catalog number 50051) should
be stored in a clean, dust free environment.
IV. CALIBRATION PROCEDURES
(A) SECONDARY STANDARD SET (optional) Catalog No. 19887
HF Secondary Standards are recommended and certified by HF scientific. They are traceable to
freshly prepared formazin primary standards. These standards are very easy to use off the shelf anytime
without preperation making them an ideal turbidity standard. A Certified of Traceability is available on
request to HF scientific Customer Service Depatartment. HF Secondary Standards may be used for calibra-
tion of all HF turbidimeters. Order from HF scientific, inc.
NOTE: NOTE: NOTE: NOTE: NOTE: Do not fr Do not fr Do not fr Do not fr Do not freez eez eez eez eeze standar e standar e standar e standar e standards. Do not lea ds. Do not lea ds. Do not lea ds. Do not lea ds. Do not leav v v v ve standar e standar e standar e standar e standards in the measur ds in the measur ds in the measur ds in the measur ds in the measuring w ing w ing w ing w ing well f ell f ell f ell f ell for e or e or e or e or extended per xtended per xtended per xtended per xtended periods. iods. iods. iods. iods.
Do not shake standards. Do not shake standards. Do not shake standards. Do not shake standards. Do not shake standards.
Specific instructions for the usage of the certified Secondary Standard are included with the kit.
Each Secondary Standard Kit contains:
-- Instructions
-- 0.02 Reference Standard
-- Certified Secondary Standard 8.00 and 800 NTU are contained in preselected cuvettes with
light sheild caps.
-- A sturdy storage case.