V-Lux: Multi-parameter fluorometer configured to detect either Algae, Aromatic Hydrocarbons or Tryptophan-like fluorescence

V-Lux: Multi-parameter fluorometer configured in situ detection of either Algae, Aromatic Hydrocarbons or Tryptophan like fluorescence.

Chelsea Technologies Group’s V-Lux is a miniature multi-parameter fluorometer configured to provide high quality in situ detection of either Algae, Aromatic Hydrocarbons or Tryptophan-like fluorescence. Fluorescence is automatically corrected for turbidity, absorbance and temperature to provide robust data collection over extended deployments.

Monitoring Applications:

Environmental pollution
Algal monitoring
Sewage and bathing waters
Oil spill including road and airport apron run-off
Point source pollution
Biological Oxygen Demand (BOD) indication
Coloured Dissolved Organic Matter (CDOM)
Exhaust gas scrubber wash water

Applications

Environmental pollution
Algal monitoring
Sewage and bathing waters
Oil spill
Point source pollution
Pollution monitoring for ports and coastal areas
Road and airport apron run-off
Biological Oxygen Demand (BOD) indication
Coloured Dissolved Organic Matter (CDOM)
Exhaust gas scrubber wash water

Features

High sensitivity
Temperature, Turbidity and Absorbance correction
Extended linear dynamic range
Turbidity measurement ISO 7027:1999 compliant
Long term calibration stability
6000m depth rating
Direct comparison of fluorometer channels via Quinine Sulphate calibration (QSU)
Internal logging capability
Flexible data output options
Integrated biofouling protection
Data acquisition software
Open data, IoT compatible (Metadata provided)
Compatible with CTG’s Hawk and Watchkeeper data logging devices

Introduction

The V–Lux is a cost effective, miniaturized, multi-parameter sensor providing
robust data collection for either UV or visible fluorescence monitoring.

Parameter	V-Lux (BTEX)	V-Lux (Crude)	V-Lux (Tryptophan)	V-Lux (Algae)
BTEX	√
PAH		√
Tryptophan			√
CDOM	√	√	√
Chlorophyll-a & -c	√	√	√	√
Chlorophyll-b & -c				√
Phycoerythrin				√
Phycocyanin				√
Absorbance	√	√	√	√
Turbidity	√	√	√	√

Available V-Lux configurations

How does it work?

Fluorescence Excitation Emission Matrix (EEM) from an environmental water sample.

CTG’s V-Lux detects fluorescence from aromatic or heterocyclic compounds. Fluorescence intensity is directly proportional to concentration and the technique is widely recognized as one of the most sensitive detection methods available. In real world deployments, however, the measured fluorescence can be quenched by high levels of turbidity and/or absorbance in the sample, leading to an under-reporting of the measured concentration. This can limit the use of fluorescence for some applications. To combat this, V-Lux measures both the solution’s turbidity and its absorbance and uses a proprietary correction algorithm to provide robust measurements over a wide range of sample interferences. This also has the added benefit of extending the linear dynamic range of the fluorometer by at least a factor of 10.

V-Lux is available in two basic configurations targeting either UV or visible fluorescence. At UV wavelengths there can be significant spectral overlap between the various fluorescing compounds, which can reduce the selectivity of the measurement.

To combat this, the UV variants of V-Lux provides three fluorescence channels. A common excitation wavelength is used so that interferences are common to all three channels. More specific detection can then achieved by taking a ratio of the outputs from the different channels to eliminate the common interference effects.

The main PAH fluorescence channel in the UV variants are configured to target BTEX, PAH or Tryptophan detection. All UV variants then have Chlorophyll-a and CDOM channels to help identify false positives arising from UV fluorescence from algae and/or non-specific background CDOM fluorescence. The traceable relative fluorescence (QSU) calibration implemented for each channel ensures that fluorescence outputs can be directly compared, without reference to the specific calibration compounds used.

The V-Lux (Algae) operates differently to the UV variants. Four discrete excitation wavelengths are used to target common algal pigment groups across the visible spectrum. Light absorbed by these pigments is rapidly transferred to a Chlorophyll-a molecule and the arising fluorescence is then detected. By monitoring the changes in Chlorophyll-a fluorescence as a function of excitation wavelength, it is then possible to detect changes in algal group composition, e.g. at the onset of a cyanobacterial algal bloom. Again, the calibration allows direct comparison to be made between the fluorescence signals generated by each excitation wavelength.

Configuration

The small size and low power consumption of the V-Lux makes it ideal for integrating into marine monitoring platforms including fixed stations, profiling CTDs, AUVs, Wave Gliders, towed vehicles, FerryBox systems and Exhaust Gas Scrubber waste water monitors.

The V-Lux incorporates a data logger and can be configured to output real time data in the following output formats: RS232, RS422, RS485, MODBUS and SDI-12. Metadata is provided to validate sensor performance and data quality. These features, together with integral biofouling protection, makes the V-Lux ideally suited to long term
monitoring applications.

V-Lux is also compatible with CTG’s Watchkeeper and Hawk data loggers, providing complete system solutions for both portable and in-line systems. A USB dongle and logging software are available for connecting directly to a PC.

A flow-through manifold is available for in-line applications and specific cables can be provided for connecting to suitable third party equipment.

Specification

Optical Specifications

Parameter	Dynamic range		Sensitivity
V-Lux (BTEX)
BTEX fluorescence	0 – 50 QSU	0.06 QSU
	0 – 10,000 μg/l (p-TSA)	3 μg/l (p-TSA)
CDOM fluorescence	0 – 6000 QSU	0.03 QSU
	0 - 500 μg/l (Perylene)	0.003 μg/l (Perylene)
Chlorophyll-a fluorescence	0-1300 QSU*	0.002 QSU
	0 - 7000 μg/l Chlorophyll-a)	0.01 μg/l (Chlorophyll-a)
Absorbance	0 - 3.5 cm-1	0.002 cm-1
Turbidity	0 - 1000 FNU	0.01 FNU
V-Lux (Crude)
PAH fluorescence	0 – 6000 QSU	0.03 QSU
	0 - 800 μg/l (Carbazole)	0.005 μg/l (Carbazole)
CDOM fluorescence	0 – 6000 QSU	0.03 QSU
	0 - 500 μg/l (Perylene)	0.003 μg/l (Perylene)
Chlorophyll-a fluorescence	0-1300 QSU*	0.002 QSU
	0 - 7000 μg/l (Chlorophyll-a)	0.01 μg/l (Chlorophyll-a)
Absorbance	0 - 3.5 cm-1	0.002 cm-1
Turbidity	0 - 1000 FNU	0.01 FNU
V-Lux (Tryptophan)
Tryptophan fluorescence	0 – 6000 QSU	0.03 QSU
	0 – 12000 μg/l (Tryptophan)	0.04 μg/l (Tryptophan)
CDOM fluorescence	0 – 6000 QSU	0.03 QSU
	0 - 500 μg/l (Perylene)	0.003 μg/l (Perylene)
Chlorophyll-a fluorescence	0-1000 QSU*	0.002 QSU
	0 - 7000 μg/l (Chlorophyll-a)	0.01 μg/l (Chlorophyll-a)
Absorbance	0 - 3.5 cm-1	0.002 cm-1
Turbidity	0 - 1000 FNU	0.01 FNU
V-Lux (Algae)
Chlorophyll-a & -c fluorescence Chlorophyll-b & -c fluorescence Phycoerythrin fluorescence Phycocyanin fluorescence	0-1800 QSU		0.003 QSU
	0 - 7000 μg/l (Chlorophyll-a)		0.01 μg/l (Chlorophyll-a)
Absorbance	0 - 3.5 cm-1		0.002 cm-1
Turbidity	0 - 1000 FNU		0.01 FNU

Mechanical Specification

Description	Specification
Dimensions	Diameter: 50mm
	Length: 158mm (excluding connector)
Weight in air	900g
Material	Housing: Titanium
	Windows: Sapphire
	Window Bezels: Copper or Titanium
	O-rings: Nitrile Rubber
Operating temperature range	-4°C to 55°C
Depth rating	6000 metres
Anti-fouling protection	UV illumination Copper bezels Coated windows A wiper accessory is available

Electrical Specification

Description	Specification
Connector	6-pin Impulse MCBH-6-MP-SS (standard) 8-pin Impulse MCBH-8-MP-SS (option)
Input voltage	9 to 72 Vdc
Data output options	RS232 RS422 RS485 MODBUS SDI-12
Power requirements	<2 Watt @ 12 Volt
Warm up time	2 seconds

In view of our continual improvement, the designs and specifications of our products may vary from those described.

V-Lux: Multi-parameter fluorometer configured to detect either Algae, Aromatic Hydrocarbons or Tryptophan-like fluorescence

Applications

Features

Introduction

How does it work?

Configuration

Specification

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