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 Product Information
Last update:
September 4, 2008
For some analytes, automating the chemistry is the easy part; it's the sample
preparation that really requires innovation to increase your laboratory's productivity.
Lachat Instruments' suite of in-line sample preparation and determination methods
thoroughly automates tedious, time-consuming, expensive and error-prone manual methods.
The suite of automated in-line modules includes
cyanide,
total nitrogen,
total phosphorus,
phenolics and
surfactants.
In-Line Total Cyanide
In order for total cyanide to be determined, a digestion and distillation of the sample
are required. Both of these steps are very time-consuming and prone to introducing error
into the determination. The In-Line Cyanide System automatically performs these functions
including:
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Heated digestion of sample in phosphoric acid |
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UV-irradiation of the mixed stream to break down metal-cyanide complexes |
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Heating of sample to vaporize the cyanide and drive it across a gas diffusion block where it is trapped by a flowing stream of sodium hydroxide |
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Determination of cyanide by automated colorimetry |
In-Line Total Nitrogen
A high temperature sample digestion is required prior to the determination of total
nitrogen. This is often accomplished using a block digestor which is bulky, expensive
and slow. In contrast, the in-line total nitrogen method completely automates the test as
follows —
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Heating and digestion of sample in a persulfate/borate reagent |
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UV irradiation |
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Determination of total nitrogen as nitrate-N |
In-Line Total Phosphorus
A high temperature sample digestion is required prior to the determination of total
phosphorus. This is often accomplished using a block digestor which is bulky, expensive
and slow. In contrast, the in-line total phosphorus method completely automates the test
as follows —
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Heating and sequential digestion of sample in sulfuric acid and potassium persulfate |
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UV irradiation |
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Determination of total phosphorus as phosphate-P |
In-Line Phenolics
Prior to determination of total recoverable phenolics, samples must be distilled. This
is often done using a classical macro glass distillation apparatus which is bulky, slow
and expensive. In contrast, the in-line phenolics method completely automates the process
including —
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Heating of sample |
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Distillation across a semi-permeable membrane |
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Condensation of sample |
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Colorimetric determination of phenol |
In-Line Surfactants
The manual determination of surfactants (also called methylene blue active substances)
includes an extremely complex, time-consuming and error prone extraction method which also
involves exposure to chloroform. The Lachat in-line surfactants method thoroughly automates
both the extraction and colorimetric determination and maintains the chloroform in a closed
system to minimize exposure with the following steps —
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Injection of sample into alkaline methylene blue |
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Segmentation of sample/alkaline methylene blue stream with chloroform |
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Extraction into chloroform to remove the negative interference from proteinaceous materials |
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Back-extraction with acidified methylene blue to remove positive interference from other ionic species |
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Measurement of absorbance |
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