What is chlorophyll?
a?
Chlorophyll is a green pigment in plants that produces energy under light.
-
Photosynthesis. The amount of photosynthesis plants (algae or phytoplankton) in the sample can be measured indirectly by measuring chlorophyll. Chlorophyll
a
Pigments are suitable for all plant species, while other chlorophylls (such as
b
,
C1
,
C2
,
d
,
f
) Applicable only to certain plants, algae or cyanobacteria, which can be used to indicate the presence of some major algal groups. The Thermo Scientific UV spectrophotometer can measure chlorophyll more accurately.
Why measure chlorophyll
a?
The influx of nutrients (such as phosphorus and nitrogen) into inland or coastal waters can cause algae to grow wild. Subsequent decay will reduce the amount of sample in the water and affect the living environment of fish, shellfish, crustaceans and other organisms. The picture on the right illustrates chlorophyll
a
And dissolved inorganic nitrogen (
DIN
)
2
Relevance. Changes in nutrient loading can also alter the composition and diversity of the total phytoplankton population.
High algae concentration indicates deterioration of water quality, while low water quality is good. The increase in phytoplankton will make the water turbid, affecting the growth of seaweed and related fisheries. In some extreme events, eutrophication causes hypoxia (anoxic
"
dead zone
â€
It kills fish, shellfish and crustaceans) outbreaks of toxic and harmful algae. In terms of water quality, chlorophyll
a
It is the best and most direct method in the existing means to measure the quantity and quality of phytoplankton and potentially cause water turbidity and low dissolved oxygen damage.
3
Chlorophyll
a
Unit is
Gg/L
or
Mg/L
Generally considered to be more than
100μg/L4
The amount will have an impact on fish. Even the cleanest water will contain near
5μg/L5
Chlorophyll
a
. There are specific water quality standards for different uses and targets of water bodies. Accurately speaking, the Thermo Scientific UV-Visible Analyzer can pass chlorophyll
a
The test to determine the specific condition of the water quality.
Which users need to measure
Chlorophyll
A (chlorophyll a)?
Waterworks with surface water storage reservoirs need to measure chlorophyll
a
To control the water source. This usually involves predicting and controlling algal blooms or identifying water intake points that avoid algae entry to avoid plugging of the filtration system, increased organic loading, and causing public health damage, and additional processing must be required. Measuring chlorophyll in the United States
a
The institutions are: US Army Corps of Engineers,
US EPA
National Environmental Protection Agency, State Environmental Protection Agency and Laboratory; Chesapeake Bay Project,
USGS
US Geological Survey,
NOAA
National Oceanic and Atmospheric Administration, Florida
Audobon
, academic institutions, etc.
How to measure
Chlorophyll
a (chlorophyll a)?
A known amount of water sample is filtered, typically a glass fiber filter. The filter needs to be ground in an acetone solution and then processed and analyzed. There are usually three standard methods for measuring chlorophyll
a
: Spectrophotometry, Fluorescence, High Performance Liquid Chromatography (
HPLC
). Spectrophotometry is the most common method in the laboratory, and sample processing usually only needs
1-5
Minutes, the general lower limit is
0.08 mg/L6
(use
1cm
The colorimetric pool), the instrument cost is also very low.
HPLC
Ability to distinguish between chlorophyll types and auxiliary pigments, but measurement is time consuming and technically demanding, generally
20-25
Minutes to process the sample.
1
station
HPLC
May be able to buy
10
A very good spectrophotometer, and the cost of subsequent consumables is also very high. Indirect measurement of chlorophyll by fluorescence
a
More suitable for remote monitoring.
The spectrophotometer used requires a narrower spectral bandwidth and multiple wavelengths to measure. Use as a three-color method
750nm
(turbidity correction),
664nm
Chlorophyll
a
),
647nm
Chlorophyll
b
Correct) and
630nm
Chlorophyll
C1
,
C2
Correction). Left picture
7
Chlorophyll
a
with
b
Absorption spectrum. Another alternative is to use before and after acidification.
750
,
664
,
665nm
To measure pheophytin
a
And interference with turbidity. The wavelengths and equations are chosen according to the chosen method. Approved chlorophyll
a
The test methods are:
US EPA 446.0
,
Standard Methods 10200H
,
ASTM D3731
,
DIN 38412-16
,
ISO 10260
Wait. measuring
Chlorophyll
a (chlorophyll a )
More equipment, there are
Liquid chromatography
,
UV spectrophotometer
Etc., recommended equipment
Thermo Scientific Orion AquaMate 8000
UV-visible water quality analyzer for measuring chlorophyll
a
Reliable performance, outstanding performance, in line with the requirements of the above test methods. The instrument spectrum is only wide
1.8nm
, covering all required wavelengths, can be used from
1-10cm
The colorimetric cell (bottle) provides accurate, reliable and convenient measurement performance.
Other accessories, consumables, including:
• 1 cm (10 mm)
Glass cuvette,
PN 331709-000
•
Wavelength accuracy and instrument performance verification standard filters,
PN 333150,
•
Standard Filter Recalibration Service
(PN 333150) , PN 701-101600
•
Spectrophotometer performance calibration service (once a year)
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