Table 2.

Comparison of different solid adsorbent in the determination of Cr(VI) by various spectroscopic techniques

Material	Type of modificator	Amount of adsorbent, mg	Sample volume, mL	pH	qmax, mg⋅g−1	Detection technique	LOD, ng⋅mL−1	Matrix	Ref.
Fe3O4/SiO2	AAMDMSa	25	45	5.0	–	FAAS	1.1	Water samples	[2]
UVM-7b	APTES	120	100	2.0	172	FAAS	1.2	Water samples	[30]
Fe3O4@INPsc	APTES	500	500	3.0	2.5	FAAS	0.29	Water samples	[31]
Fe3O4@GO	TETAd	50	50	2.0	16	FAAS	1.4	Environmental water	[3]
SBA-15e	APTES	15	10	2.0	–	FAAS	0.2	Water samples	[32]
Fe3O4	PAEDTsf	14.8	400	2.0	–	ETAAS	0.001	Water and tea samples	[4]
Fe3O4@MnO2,Al2O3	AAPTMSg	250	5	6.0	30	ICP-OES	0.02	River water samples	[6]
CuNCsh	DAMPi	4uM	25	9.0	–	ICP-OES	0.016	Drinking, tap and groundwater	[7]
MCM-41j	APTMSk	25	100	9.0	111	ICP-OES	4	Water samples	[33]
TRGl	APTES	20	25	1.7	–	UV-Vism	0.4	Tap, river, sewage and ground water	[34]
Fe3O4	PANIn	14.5	100	7.6	54	HPLC	0.1	Spiked water samples	[35]
CNTs	Aliquat 336o	5	20	2	–	TXRFp	3	Tap and mineral water	[36]
GO	APTES	5	50	3.5	13.3	EDXRF	0.17	Environmental water	This work

^a2-aminoethyl-3-aminobutylmethyldimethoxysilane; ^bbimodal mesoporous silica nanoparticles; ^cmagnetic Cr(VI)-imprinted nanoparticles; ^dtriethylenetetramine; ^emesoporous silica SBA-15; ^f2-(propylaminoethyl)dithiocarbamate; ^g3-(2-aminoethylamino)propyl]trimethoxysilane, ^h copper nanoclusters; ⁱ4,6-diamino-2-mercaptopyrimidine; ^jmesoporous silica MCM-41; ^k3-aminopropyltrimethoxysilane; ^lthermally reduced graphene; ^mUV-Vis spectrophotometry; ⁿpolyaniline; ^otricaprylmethylammonium chloride; ^ptotal-reflection X-ray fluorescence spectrometry