A graphene oxide/gold nanoparticle-based amplification method for SERS immunoassay of cardiac troponin I.

Cardiac troponin I (cTnI) was considered as the "gold standard" for acute myocardial infarction (AMI) diagnosis owing to its superior cardiac specificity for cardiac damage and showing little or no changes in patients with a skeletal muscle disease or trauma. Herein, a new signal amplification surface-enhanced Raman scattering (SERS) platform was developed for recognition and detection of cTnI by using gold nanoparticles (AuNPs), graphene oxide (GO) and magnetic beads (MB). Here, antibody/Raman reporter labeled AuNP-functionalized GO were employed as both SERS nanotags and signal amplification carriers. Monoclonal antibody modified MB were applied as the capture probe and separation agents. In the presence of cTnI, sandwich type immunocomplexes, "capture probe/target/SERS nanotags", were formed through antibody-antigen-antibody interactions. Due to the strong SERS enhancement ability of the designed GO/AuNP complexes and a high binding chance between cTnI and the GO/AuNP complexes, the proposed SERS-based immunoassay could selectively detect cTnI with a high sensitivity (detection limit of 5 pg mL-1) and a good linearity was obtained in a range of 0.01-1000 ng mL-1. In addition, this method was also successfully applied for detecting cTnI in serum substitute media with a similar linear range. Furthermore, this strategy can be constructed with different kinds of antibodies and Raman reporters, and thus can be easily used for simultaneous detection of multiple biomarkers. Therefore, this proposed SERS-based signal amplification technique shows strong potential for the clinical diagnosis of AMI disease.

Tris(2,2'-bipyridine)-nickel(II) hexa-molybdate.

The asymmetric unit of the title compound, [Ni(C(10)H(8)N(2))(3)][Mo(6)O(19)], consists of one complex [(Ni(C(10)H(8)N(2))(3)](2+) cation and one Lindqvist-type [Mo(6)O(19)](2-) polyanion. The Ni(2+) ion is in a distorted octa-hedral coordination by six N atoms from three chelating 2,2'-bipyridine ligands. The Lindqvist-type anion exhibits the characteristic Mo-O bond-length distribution, with the shortest bonds being the Mo-O(terminal) bonds [mean = 1.679 (2) Å] and the longest being those to the central O atom [mean = 2.318 (7) Å]. A number of C-H⋯O inter-actions contribute to the crystal packing.

Bis{tris-[3-(2-pyrid-yl)-1H-pyrazole]zinc(II)} dodeca-molybdosilicate hexa-hydrate.

The asymmetric unit of the title compound, [Zn(C(8)H(7)N(3))(3)](2)[SiMo(12)O(40)]·6H(2)O, consists of a complex [Zn(C(8)H(7)N(3))(3)](2+) cation, half of a Keggin-type [SiMo(12)O(40)](4-) heteropolyanion and three uncoordinated water mol-ecules. The Zn(2+) cation is surrounded in a distorted octa-hedral coordination by six N atoms from three chelating 3-(2-pyrid-yl)pyrazole ligands. In the heteropolyanion, two O atoms of the central SiO(4) group ( symmetry) are equally disordered about an inversion centre. N-H⋯O hydrogen bonding between the cations, anions and the uncoordinated water mol-ecules leads to a consolidation of the structure.

Bis{tris-[3-(2-pyrid-yl)-1H-pyrazole]nickel(II)} dodeca-molybdosilicate tetra-hydrate.

The asymmetric unit of the title compound, [Ni(C(8)H(7)N(3))(3)](2)[SiMo(12)O(40)]·4H(2)O, consists of a complex [Ni(C(8)H(7)N(3))(3)](2+) cation, half of a Keggin-type heteropolyanion [SiMo(12)O(40)](4-) and two uncoordinated water mol-ecules. The Ni(2+) cation is surrounded in a slightly distorted octa-hedral coordination by six N atoms from three chelating 3-(2-pyrid-yl)-1H-pyrazole ligands. In the heteropolyanion, two O atoms of the central SiO(4) group ( symmetry) are equally disordered about an inversion centre. N-H⋯O and O-H⋯O hydrogen bonding between the cations, anions and the uncoordinated water mol-ecules leads to a consolidation of the structure.

Tris{aqua-bis[3-(2-pyrid-yl)-1H-pyrazole]copper(II)} di-µ(9)-arsenato-hexa-triaconta-µ(2)-oxido-octa-deca-oxidoocta-deca-molybdate(VI).

The title compound, [Cu(C(8)H(7)N(3))(2)(H(2)O)](3)[As(2)Mo(18)O(62)], consists of two subunits, viz. an α-Dawson-type [As(2)Mo(18)O(62)](6-) anion and a complex [Cu(C(8)H(7)N(3))(2)(H(2)O)](2+) cation. The copper(II) ion (site symmetry .2) is penta-coordinated in a distorted square-pyramidal manner by four N atoms from two chelating 3-(2-pyrid-yl)pyrazole ligands in equatorial positions and one water mol-ecule in the apical position. In the heteropolyanion, two O atoms of the AsO(4) group (3. symmetry) are equally disordered about the threefold rotation axis. N-H⋯O and O-H⋯O hydrogen bonding between the neutral mol-ecules and the water mol-ecules leads to a consolidation of the structure.

Bis{tris-[3-(2-pyrid-yl)-1H-pyrazole]iron(II)} tetra-deca-molybdo(V,VI)silicate.

The asymmetric unit of the title compound, [Fe(C(8)H(7)N(3))(3)](2)[SiMo(14)O(44)], consists of a complex [Fe(C(8)H(7)N(3))(3)](2+) cation and half of a derivative of an α-Keggin-type anion, [SiMo(14)O(44)](4-). In the mixed-valent Mo(V/VI) anion, the α-Keggin type core is capped on two oppositely disposed tetra-gonal faces by additional (MoO(2)) units. The [SiMo(14)O(44)](4-) anion shows disorder. Two O atoms of the central SiO(4) group ( symmetry) are equally disordered about an inversion centre. Moreover, two of the outer bridging O atoms and the O atoms of the capping (MoO(2)) unit are likewise disordered. The Fe(2+) cation is surrounded in a slightly distorted octa-hedral coordination by six N atoms from three 3-(2-pyrid-yl)-1H-pyrazole ligands. N-H⋯O hydrogen bonding between the cations and anions leads to a consolidation of the structure.

(µ-Oxalato-κO,O:O,O)bis-[bis-(2,2'-bipyridine-κN,N')cobalt(II)] µ(6)-oxido-dodeca-µ(2)-oxido-hexa-oxido-hexa-tungstate(VI).

The asymmetric unit of the title compound, [Co(2)(C(2)O(4))(C(10)H(8)N(2))(4)][W(6)O(19)], consists of one half of the complex [Co(2)(C(2)O(4))(C(10)H(8)N(2))(4)](2+) cation and one half of the Lindqvist-type [W(6)O(19)](2-) isopolyanion. Both constituents are completed by crystallographic inversion symmetry. In the dimeric cation, the Co(II) atom is surrounded in a distorted octa-hedral coordination by four N atoms from two chelating 2,2'-bipyridine ligands and by two O atoms from the chelating oxalate anion. The Lindqvist-type anion exhibits the characteristic W-O bond-length distribution, with the shortest bonds being the W-O(terminal) bonds and the longest being those to the central O atom.

Poly[bis-(µ-hemihydrogen 2-phenyl-quinoline-4-carboxyl-ato-κN,O)silver(I)].

In the title compound, [Ag(C(16)H(10.5)NO(2))(2)], the Ag(I) cation (site symmetry 2) is coordinated by two N atoms in a near-linear AgN(2) arrangement. Two carboxyl-ate O atoms from two additional 2-phenyl-quinoline-4-carboxyl-ate ligands form long Ag-O bonds [2.6585 (17) Å], resulting in a distorted square-planar arrangement. The bridging ligands result in infinite corrugated sheets propagating in (010). An O-H⋯O hydrogen bond, disordered about a twofold axis, completes the structure.

Erratum: Poly[bis-(µ-hemihydrogen 2-phenyl-quinoline-4-carboxyl-ato-κN,O)silver(I)]. Corrigendum.

The affiliation of one of the authors in the paper by Zhang, Wei & Li [Acta Cryst. (2009), E65, m223] is corrected.[This corrects the article DOI: 10.1107/S1600536809001184.].

Tetra-µ-oxido-tetra-kis{dioxido[3-(2-pyrid-yl)-1H-pyrazole]molybdenum(VI)}.

In the title compound, [Mo(4)O(12)(C(8)H(7)N(3))(4)], the Mo(VI) ion has a distorted octa-hedral coordination completed by two terminal O atoms, two µ-oxide atoms and two N atoms from one 3-(2-pyrid-yl)-1H-pyrazole ligand. It is noteworthy that in the tetranuclear unit ( symmetry), any three Mo(VI) atoms define a plane, and the fourth lies 1.8 (1) Šout of that plane. The degree of linearity of the oxide bridges between two Mo atoms is 175.38 (13)°. Moreover, the N-H group forms an intra-molecular hydrogen bond (four per mol-ecule).

Bis(µ-2,2'-biimidazole-κN:N)bis-[aqua-copper(I)] sulfate.

In the structure of the title compound, [Cu(2)(C(6)H(6)N(4))(2)(H(2)O)(2)]SO(4), the asymmetric unit contains half each of two 2,2'-diimidazole ligands, one Cu(+) cation, one water mol-ecule and half of a sulfate anion (2 symmetry). The dinuclear complex is completed through a twofold rotation axis, leading to a twisted ten-membered ring mol-ecule. The dihedral angle between the two symmetry-related 2,2'-diimidazole ligands is 23.6 (1)°. The copper centre is coordinated by two N atoms of two symmetry-related 2,2'-diimidazole ligands in an almost linear fashion. The water mol-ecule exhibits a weak coordination to Cu(+) with a more remote distance of 2.591 (2) Å. The distance between the two copper centres is 2.5956 (6) Å. O-H⋯O and N-H⋯O hydrogen bonds between the complex cation, the water mol-ecule and the sulfate anion lead to the formation of a three-dimensional network.

Diaqua-1κO,2κO-(2,2'-bi-1H-imidazole-1κN,N)(oxalato-2κO,O)di-µ-oxido-κO:O-dioxido-1κO,2κO-dimolyb-denum(V) trihydrate.

In the title compound, [Mo(2)(C(2)O(4))O(4)(C(6)H(6)N(4))(H(2)O)(2)]·3H(2)O, the coordination polyhedra for both Mo(V) atoms consist of two bridging O atoms, two atoms of the chelating ligand (oxalate or diimidazole), a terminal O atom and one H(2)O mol-ecule. The two distorted octa-hedrally coordinated Mo(V) atoms are linked together via O-O edge-sharing and Mo-Mo inter-actions with a Mo-Mo bond length of 2.564 (5) Å. Uncoordinated water mol-ecules are situated in the voids of the crystal structure. N-H⋯O and O-H⋯O hydrogen bonding between the neutral mol-ecules and the water mol-ecules lead to a consolidation of the structure.

Bis(6-meth-oxy-2-{[tris-(hydroxy-meth-yl)-meth-yl]-imino-meth-yl}phenolato)-copper(II) dihydrate.

In the title compound, [Cu(C(12)H(16)NO(5))(2)]·2H(2)O, the Cu(II) ion adopts a trans-CuN(2)O(4) octa-hedral geometry arising from two N,O,O'-tridentate 6-meth-oxy-2-{[tris-(hydroxy-meth-yl)meth-yl]-imino-meth-yl}phenolate ligands. The Jahn-Teller distortion of the copper centre is unusally small. In the crystal structure, O-H⋯O hydrogen bonds, some of which are bifurcated, link the component species.

Bis{2-meth-oxy-6-[tris-(hydroxy-meth-yl)methyl-imino-meth-yl]phenolato-κO,N,O'}manganese(II) dimethanol solvate hemihydrate.

In the title complex, [Mn(C(12)H(16)NO(5))(2)]·2CH(3)OH·0.5H(2)O, the Mn(II) atom has a distorted octa-hedral coordination geometry in which two N atoms from two 6-meth-oxy-2-[tris-(hydroxy-meth-yl)methyl-imino-meth-yl]phenolate ligands adopt a trans arrangement. The Mn-O(H) bonds (mean length 2.134 Å) are significantly longer than the Mn-O and Mn-N bonds (mean length 2.011 and 2.027 Å, respectively), and the dihedral angle between the mean planes through the aromatic rings of the two ligands is 76.8 (1)°. A complex network of O-H⋯O hydrogen bonds is formed between the complexes and the uncoordinated methanol and water mol-ecules. The C and O atoms of one C-OH group are disordered with equal occupancies.

Aqua-azido-{2,2'-[o-phenylenebis(nitrilo-methyl-idyne)]diphenolato}manganese(III) hemihydrate.

In the title compound, [Mn(C(20)H(14)N(2)O(2))(N(3))(H(2)O)]·0.5H(2)O, the Mn(III) ion is chelated by the N,N',O,O'-tetra-dentate Schiff base ligand and further coordinated by one azide ion and one water mol-ecule in trans positions, resulting in a distorted fac-MnN(3)O(3) octa-hedral arrangement. The O atom of the uncoordinated water mol-ecule lies on a crystallographic twofold axis. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds help to establish the packing.

Diaqua-1κO,3κO-di-µ-cyanido-1:2κN:C;2:3κC:N-dicyanido-2κC-bis-{4,4'-dibromo-2,2'-[propane-1,2-diylbis(nitrilo-methyl-idyne)]diphenolato}-1κO,N,N',O';3κO,N,N',O'-1,3-di-iron(III)-2-nickel(II).

The title compound, [Fe(2)Ni(C(17)H(14)Br(2)N(2)O(2))(2)(CN)(4)(H(2)O)(2)] or [{Fe(C(17)H(14)Br(2)N(2)O(2))(H(2)O)}(2)(µ-CN)(2){Ni(CN)(2)}], is iso-structural with its Mn(III)-containing analogue. Each Fe(III) atom is chelated by a Schiff base ligand via two N and two O atoms and is additionally coordinated by a water mol-ecule, forming a slightly distorted octa-hedral geometry. The two Fe(III) centres are bridged by a square-planar Ni(CN)(4) unit, which lies on an inversion centre. A two-dimensional network is formed via O-H⋯O and O-H⋯N hydrogen bonds.

Diazido-bis(2,2'-biimidazole)manganese(II).

In the title compound, [Mn(N(3))(2)(C(6)H(6)N(4))(2)], the Mn atom (site symmetry ) is bonded to two azide ions and two bidentate biimidizole ligands, resulting in a slightly distorted octa-hedral MnN(6) geometry for the metal ion. In the crystal structure, N-H⋯N hydrogen bonds help to consolidate the packing.

[Microchip capillary electrophoresis-electrochemical detection of nitrite using a modified carbon paste electrode].

Carbon paste electrode modified with 3-mercaptopropyltrimethoxysilane copper (MPTMS-Cu) encapsulated in molecular sieve MCM-41 was prepared. The electrocatalytic behavior of the modified electrode towards the reduction of nitrite was studied in detail, including pH-dependence and composition-dependence studies. A microchip capillary electrophoresis-electrochemical detection system with the modified carbon paste as electrode was fabricated. The application of the system for the detection of nitrite is discussed. The detection was finished within 40 s under the following conditions: 50 mmol/L sodium acetate buffer at pH 5.8, -1.6 kV running voltage. The peak current was linear with the concentration of nitrite over 10.0 micromol/L-5.0 mmol/L and the detection limit was 4.0 micromol/L in pure water.

[Determination of alkaloids from Coptis chinensis Franch. and Phellodendron amurense Rupr. Decocted together in baitouweng decocta by high performance capillary electrophoresis].

A rapid and accurate method for determining alkaloids from Coptis chinensis Franch, and Phellodendron amurense Rupr, decocted together in Baitouweng decocta was established. Experiments were carried out on a self-assembled capillary electrophoresis system. The experimental conditions were as follows: 75 microns i.d. x 50 cm fused silica capillary, 0.05 mol/L Na2B4O7-CH3OH (85:15, V/V) as buffer, applied voltage 14 kV and detection wavelength 232 nm. In addition, the concentration of ethanol in the extraction solvent was optimized. Experimental results showed that ethanol-water (30:70, V/V) was the ideal solvent to extract the main effective ingredients from Coptis chinensis Franch. and Phellodendron amurense Rupr. decocted together in Baitouweng decocta. Berberine and palmatine had good linearities in the range of 15.0 mg/L-65.0 mg/L and 12.5 mg/L-50.0 mg/L respectively, and their average recoveries were 95.5%-104% (RSD 2.7%-6.9%) and 92.1%-103% (RSD 4.5%-6.7%) respectively.