Sensing Application — Hydrolytically Stable Luminescent Cationic Metal Organic Framework for Highly Sensitive and Selective Sensing of Chromate Anions in Natural Water Systems

4 measurement groups · 26 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

Chromate adsorption kinetics and sorption isotherm monitored by ICP-MS or UV-vis

UV-visible and optical absorption spectroscopy Bulk elemental and compositional analysis

finely ground powder of 1 · Powder

Kinetics: 150 mg powder in 60 mL of 1 ppm K2Cr2O7; filtered with 0.22 um nylon membrane and monitored by ICP-MS. Isotherm: 12 mg powder in 6 mL K2Cr2O7 solutions from 0.2 to 300 ppm, stirred 24 h, monitored by UV-vis at CrO4^2- absorption near 350 nm.

Atmosphere: aqueous, room temperature for exchange experiments
Context: pristine framework adsorbing chromate
Measurement source: p002 and p005 / article pp.16449, 16452 · Experimental Section; Results and Discussion - Sensing Property · Figure 4c,d; Figures S10-S11

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
chromium uptake after 1.5 min at 1 ppm	76.3% within 1.5 min (equilibrium 84.1%)	—	—	Text Exact Reported	p005 / article p.16452 · Results and Discussion - Sensing Property · Figure 4c
maximum chromate adsorption capacityMarked as a best value within this paper	about 9.7 mg (Cr)/g	—	about	Text Approximate	p005 / article p.16452 · Results and Discussion - Sensing Property · Figure 4d
equilibrium chromium uptake at 1 ppm	equilibrium 84.1%	—	—	Text Exact Reported	p005 / article p.16452 · Results and Discussion - Sensing Property · Figure 4c
adsorption equilibrium time at 10 ppm chromate	reaches equilibrium within 20 min	—	within	Text Rounded Reported	p005 / article p.16452 · Results and Discussion - Sensing Property · Figure S10
Langmuir sorption isotherm R2	R2 = 0.98	—	—	Text Exact Reported	p005 / article p.16452 · Results and Discussion - Sensing Property · Figure 4d
CrO4^2- uptake in competing Sr2+/CrO4^2- experiment after 10 min	38.6% of CrO4^2- anions within 10 min; equilibrium 45.6%	—	—	Text Exact Reported	p003 / article p.16450 · Results and Discussion - Structure and General Characterizations · Figure S11
CrO4^2- equilibrium uptake in competing Sr2+/CrO4^2- experiment	equilibrium 45.6%	—	—	Text Exact Reported	p003 / article p.16450 · Results and Discussion - Structure and General Characterizations · Figure S11

Concentration-dependent luminescence quenching in deionized-water K2Cr2O7 solutions

Photoluminescence and fluorescence spectroscopy

finely ground powder of 1 · Powder

3 mg of finely ground 1 in 2 mL K2Cr2O7 solution from 1 to 300 ppm for wide-range spectra; for detection limit, solid/liquid ratio reduced from 1.5 to 0.5 mg/mL and low concentration 0-10 ppm measured. Ultrasonication for 1.5 min; spectra recorded three times.

Atmosphere: aqueous
Context: pristine framework dispersed in chromate-containing water
Measurement source: p002 and p005-p006 / article pp.16449, 16452-16453 · Experimental Section; Results and Discussion - Detection Limit · Figures 4 and 6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
chromate detection limit in deionized waterMarked as a best value within this paper	0.56 ppb	—	—	Text Exact Reported	p005 / article p.16452 · Results and Discussion - Detection Limit · Figure 6; Table S5
low-concentration calibration slope in deionized water	y = 12.84x + 1.7156	—	—	Visual Estimate Approximate	p006 / article p.16453 · Results and Discussion - Detection Limit · Figure 6b
standard error of blank deionized water luminescence	ISE: deionized water 52.12	—	—	Caption Exact Reported	p011 / SI p.S-11 · S9. Detection limits in Dushu lake water and seawater · Figure S15
linear transformed concentration calibration R2	R2 = 0.9999	—	—	Text Exact Reported	p005 / article p.16452 · Results and Discussion - Sensing Property · Figure 4b inset
monitored Eu3+ sensing transition wavelength	616 nm	—	—	Text Exact Reported	p004 / article p.16451 · Results and Discussion - Sensing Property · Figure 4
luminescence quenching at 30 ppm chromate	impaired by about 76.5% of the initial value at 30 ppm	—	about	Text Approximate	p004 / article p.16451 · Results and Discussion - Sensing Property · Figure 4a
Langmuir fit R2 for luminescence quenching ratio	R2 = 0.9996	—	—	Text Exact Reported	p005 / article p.16452 · Results and Discussion - Sensing Property · Figure 4b
SI comparison-table detection limit for this workMarked as a best value within this paper	[Eu7(mtb)5(H2O)16].NO3.8DMA.18H2O detection limit 0.56 ppb	—	—	SI Table Exact Reported	p014 / SI p.S-14 · S9. Detection limits in Dushu lake water and seawater · Table S5

Concentration-dependent luminescence sensing in Dushu Lake water and synthetic seawater

Photoluminescence and fluorescence spectroscopy

finely ground powder of 1 · Powder

Fresh Dushu Lake water and seawater made by dissolving 3.2 g sea salt in 100 mL deionized water; pH adjusted to about 4 with 0.1 M HNO3; concentration-dependent luminescence spectra collected using same procedure as deionized water.

Atmosphere: natural/simulated high-ionic-strength aqueous media
Context: pristine framework dispersed in natural-water matrices
Measurement source: p007-p008 / article pp.16454-16455 · Results and Discussion - Selectivity · Figures 8 and 9; Figures S16-S19

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
chromate detection limit in Dushu Lake water	2.88 ppb	—	—	Text Exact Reported	p007 / article p.16454 · Results and Discussion - Selectivity · Figure 9; Figure S17
chromate detection limit in seawater	1.75 ppb	—	—	Text Exact Reported	p007 / article p.16454 · Results and Discussion - Selectivity · Figure 9; Figure S19
low-concentration calibration slope in Dushu Lake water	y = 10.98x + 1.72	—	—	Visual Estimate Approximate	p012 / SI p.S-12 · S9. Detection limits in Dushu lake water and seawater · Figure S17
low-concentration calibration slope in seawater	y = 4.805x - 0.4	—	—	Visual Estimate Approximate	p013 / SI p.S-13 · S9. Detection limits in Dushu lake water and seawater · Figure S19
standard error of blank Dushu Lake water luminescence	ISE: Dushu lake water 208.47	—	—	Caption Exact Reported	p011 / SI p.S-11 · S9. Detection limits in Dushu lake water and seawater · Figure S15
standard error of blank seawater luminescence	ISE: seawater 52.12	—	—	Caption Exact Reported	p011 / SI p.S-11 · S9. Detection limits in Dushu lake water and seawater · Figure S15
impact of Dushu Lake water and seawater on MOF luminescence	negligible influence on luminescence intensity at 616 nm	—	—	Text Qualitative	p007 / article p.16454 · Results and Discussion - Selectivity · Figure 8

Luminescence selectivity and Stern-Volmer quenching-constant analysis

finely ground powder of 1 · Powder

5 mg of 1 dispersed in 2 mL of 100 ppm anion or cation solution; ultrasonicated 1.5 min; spectra recorded three times. KSV values calculated from I0/I = KSV[Q] + 1.

Atmosphere: aqueous
Context: pristine framework challenged with competing ions
Measurement source: p011 / SI p.S-11 · S8. Influence of competing metal ions · Table S4

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
competing cation KSV range	Na+ 0.50, Sr2+ 22.6, Al3+ 8.2, Ca2+ -13.3, Cu2+ 100.6, Mg2+ 25.5, Zn2+ 65.8	—	—	SI Table Exact Reported	p011 / SI p.S-11 · S8. Influence of competing metal ions · Table S4
Stern-Volmer quenching constant for chromate from main text	3.3 x 10^4	—	as large as	Text Rounded Reported	p006 / article p.16453 · Results and Discussion - Selectivity · Table S4
Stern-Volmer quenching constant for K2Cr2O7 solutionMarked as a best value within this paper	Cr2O7^2- KSV = 33423.9	—	—	SI Table Exact Reported	p011 / SI p.S-11 · S8. Influence of competing metal ions · Table S4
largest listed non-chromate anion KSV, NO2-	NO2- KSV = 887.4	—	—	SI Table Exact Reported	p011 / SI p.S-11 · S8. Influence of competing metal ions · Table S4