Cavity-Enhanced Spectroscopy in Condensed Phases: Recent Literature and Remaining Challenges

Table 1

Review of literature CES methods.

Absorber	Method	λ (nm)	Sample volume	Min. det. optical loss (cm^−1)	Ref.
Allura red dye, Congo red	LCW CRDS	532	<1 μL	0.00034	[31]
Malachite green	LJ CRDS	628	150 mL	0.016	[47]
Benzene	NICUV-CES	450–650	NA	0.00002	[48]
Alexa Fluor dye	NICUV-CES	400–700	2.7 mL	0.000009	[22]
Brilliant blue dye	NICUV-CRDS	630	NA	0.00005	[20]
Rhodamine 6G	NICUV-CRDS	500–600	~3 mL	0.000065	[49]
Quinalizarin	BRCUV-CRDS	470	10 μL	0.00062	[50]
Benzene	BRCUV-CRDS	580–660	NA	0.0000002	[51]
Crystal violet	LF-CRDS	532	12 μL	0.00031	[52]
Bacteriochlorophyll	LF-CRDS	783	few mL	0.000016	[53]
Cu^2+, indigo carmine	LF-CRDS	620–670	10 μL	0.000001	[54]
Methylene blue	LF-CRDS	655	60 mL	0.00000033	[55]
Sudan black, methylene blue	LF-CRDS	450–700	100 mL	0.0000003	[21]
Tartrazine	FG-CRDS	405	100 nL	0.02	[56]
Tartrazine	FG-CRDS	405	6 nL	0.11	[57]
Rhodamine	FG-CRDS	532	19 nL	0.11	[34]
Permanganate ion	FG-CRDS	532	130 nL	0.0024	[58]
Ferrozine complex	LCW	562	300 μL	0.000013	[59]
Bromothymol blue	LCW	613	1 μL	0.02	[60]

LCW: liquid core waveguide; LJ: liquid jet; CRDS: cavity ring-down spectroscopy; CES: cavity-enhanced spectroscopy; NICUV: normal incidence cuvette; BRCUV: Brewster angle cuvette; LF: liquid-filled cell in which fluid directly contacts fluid; FG: fiber gap; NA: not available.