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NPD - SRI Instruments
NPD - Nitrogen-Phosphorus Detector
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Very Selective to Nitrogen and
Phophorus
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Detects down to 100ppb
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Exceptionally rugged NPD bead
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Similar in design to the SRI FID
The SRI ceramic NPD bead is exceptionally rugged and long-lasting,
offering service from 100 to 1000 hours, depending on operating
conditions.
The Nitrogen-Phosphorus Detector responds to nitrogen-phosphorus compounds about 100,000 times more strongly
than normal hydrocarbons. Due to this high degree of selectivity, the NPD is commonly used to detect pesticides,
herbicides, and drugs of abuse.
The NPD is similar in design to the FID, except that the hydrogen flow rate is reduced to about 3mLs/minute, and
an electrically heated thermionic bead (NPD bead) is positioned near the orifice. Nitrogen or phosphorus
containing molecules exiting the column collide with the hot bead and undergo a catalytic surface chemistry reaction.
The resulting ions are attrtacted to a collector electrode, amplified and output to the data system.
This chromatogram shows the NPD
response to a 10ppm malathion
sample.
NPD/DELCD Combination Detector
DISCONTINUED
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Ideal for Pesticide Screening
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NPD detects Organo-phosphorus (OPP)
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DELCD detects Chlorinated species
The NPD/DELCD combination detector is ideal for pesticide
screening. The NPD selectively responds to the organo-
phosphorus pesticides, while the
detects only the
chlorinated species.