Development of In Situ Sensors for Chlorophyll Concentration Measurement

Table 1

Summary of fluorometers of in situ chlorophyll measurement.

Name	Light source	λex (nm)	Excitation method	Detectors	Parameters	Measurement mode	Range; (μgL^−1)	LOD; (μgL^−1)	Strengths	Weakness	References
AOA	LED	450, 525, 570(×2), 590, and 610	5 kHz	PMT	Chl a, Chl c, PC et al.	Benchtop, submersible probe	0–80	0.02	Spectral groups measurement	More spectral fingerprinting will be better	[27]
BenthoFluor	LED	370, 470, 525, 570, 590, and 610	5 kHz	PMT	Microphytobenthos	In situ	0–7 µg cm^−2	—	Sediments groups measurement	More spectral fingerprinting will be better	[28]
—	Flash xenon lamp	Two-filter 435	Flash 10–15 us	PD	Chl a	Underwater-towed bodies and moored or buoyed	0–100 or 0–1000	0.1	Remote operation	Need a platform for operation	[49, 50]
ALF	Lasers	405; 532	200 us PDP	PMT	Chl a, PC, and CDOM	Laboratory or flow-through	0.003–50	—	Spectral deconvolution	Need a platform for operation	[59]
ALF-T	Laser	510; 375, 405, and 510	PDP	Small PMT spectrometer	Chl a, PBP; CDOM	Flow-through small-volume sample	—	0.01	“T” optical scheme	Need a platform for operation	[41]
Multiexciter	LED	375, 400, 420, 435, 470, 505, 525, 570, and 590	—	Si-PD,; 680 nm	Phytoplankton	In situ	—	0.1	Nine LEDs for distinction phytoplankton groups	Not enough information to assessment	[65]
Phase fluorometer	LED	blue	Sinusoidal 80 MHz modulation	PD	Chl a	—	—	466.7	Fluorescence lifetime measurement	A worse LOD	[85]
—	LED	470	Pseudorandom sequence modulation	PD	Chl	In situ	0–25	0.0103	Pseudorandom sequence modulation, highly sensitive	Need more information of assessment	[86]
FRRf	LED	470	FRR	PMT	Chl	In situ	0–50	0.01	Profiling buoy system	Big and complex	[91]
MFF	4 xenon strobe; lamps	455	10 kHz; strobe flash	Two; PMTs; 676 nm	Chl a	In situ	0–50 and 0–200	0.1 and 0.5	Eight sensors simultaneous measurement, long term	Accuracy	[37]
ECO BBFL2	LED	370, 540, and 660	Modulated 1 k	460, 570, and 660 nm PD	Chl a, CDOM; phycoerythrin	In situ	0–125	0.025	Three-channel excitation, high accuracy	Expensive	[102]
ECO 3X1M	LED	435, 470, and 532	Modulated 1 k	PD 695 nm	Chl	In situ	0.01–125	0.095	High accuracy	Expensive	[102]
Trios MicroFlu	LED	470	Modulated	PD	Chl	In situ	0–10; 0–100	0.1	Two ranges and accuracy	Cannot simultaneously measure chlorophyll and phycocyanin	[109]
TurboMAP-L	Diode laser	410	—	PD; CMOS	Chl a and turbidity	In situ	0–100	0.5	Consider the aerodynamic design	Composition analysis	[45]
—	Blue LED	425	Modulation	PD	Chl a	Pumpable	—	—	Low cost	A little rough	[120]
	Lamp	420, 270/530	Flash	PMT	Chl	Submersible	—	—	Two probing heads, Raman scattering calibration	Cannot find the LOD	[38]
PLIF	Diode laser	532	—	CCD	Chl	In situ	—	—	Microscale fluorescence imaging	Accuracy	[93]
Lensless Miniature Portable Fluorometer	LED	405, 465	—	CMOS image sensor array	Chl, CDOM	Portable	0.625–893	0.625	Low cost, lensless, and low power	Accuracy and LOD	[43]