Picrate Research Articles

4-(2,3-Di-chloro-phen-yl)piperazin-1-ium picrate.

The title compound, C6H2N3O7 -·C10H13Cl2N2 +, crystallizes with one 1-(2,3-di-chloro-phen-yl)piperazine (DP) cation and one picrate (PA) anion in the asymmetric unit. In the crystal structure, the DP cation and PA anion are inter-connected via several N-H⋯O and C-H⋯O hydrogen bonds. The DP cation and PA anion are further connected through C-Cl⋯π [3.8201 (4), 3.7785 (4) Å] and N-O⋯π [3.7814 (4) Å] inter-actions. The DP cations are further inter-connected via a weak inter-molecular Cl⋯Cl [3.2613 (4) Å] halogen-halogen inter-action. The combination of these supra-molecular inter-actions leads to a herringbone like supra-molecular architecture.

Closing the Gap: Synthesis of Three Isomeric N,N-Ditetrazolymethane Ligands and Their Coordination Proficiency in Adaptable Laser Responsive Copper(II) and Sensitive Silver(I) Complexes.

N,N-Substituted ditetrazolylalkanes are widely used molecules in the field of coordination chemistry and are known with different alkyl chain lengths. The missing fragment within this row is presented by the elementary methylene-bridged ditetrazoles. The three different isomers (di(tetrazol-1-yl)methane (1,1-dtm, 1), (tetrazol-1-yl)(tetrazol-2-yl)methane (1,2-dtm, 2), and di(tetrazol-2-yl)methane (2,2-dtm, 3)) were synthesized in a convenient one-step reaction. All of them were successfully incorporated as neutral ligands in 15 new energetic coordination compounds (ECC) based on Cu2+ and Ag+ as well as different anions (nitrate, picrate (PA), styphnate (TNR), trinitrophloroglucinate (TNPG), and perchlorate) revealing an extraordinary coordination behavior of the ligands compared to other 5H-ditetrazolylalkanes. All compounds were extensively characterized using single-crystal X-ray diffraction experiments, infrared spectroscopy (IR), elemental analysis (EA), and differential thermal analysis (DTA). Furthermore, the sensitivities were determined using standard techniques, and Hirshfeld surface calculations of the ligands were applied to explain their significant divergences to external stimuli. The ECC possess very good exothermic decomposition temperatures up to 242 °C. The ignition of all colored complexes was tested in laser experiments, and two copper(II) perchlorate compounds showed promising results in classic initiation capability tests using pentaerythritol tetranitrate (PETN).

Hyperpolarizability, Hirshfeld, and density functional theory computations of a nonlinear optical picrate

GRAPHICAL ABSTRACT

Synthesis, Crystal Structure, Thermal and Explosive Properties of [Cd(SCZ)3(H2O)](PA)2·3H2O (SCZ = Semicarbazide, PA = Picrate)

AbstractThe heptacoordinate transition metal coordination compound [Cd(SCZ)3(H2O)](PA)2·3H2O (1) with the ligand semicarbazide (SCZ) and the counteranion picrate (PA) was synthesized and characterized by elemental analysis and FTIR spectroscopy. Single‐crystal X‐ray diffraction analysis revealed that 1 crystallizes in the monoclinic space group P21/c. The Cd2+ ion is heptacoordinated by three SCZ groups and a water molecule. SCZ presents typical bidentate coordination modes. The thermal decomposition mechanism of 1 was studied by differential scanning calorimetry (DSC), which revealed that complex 1 exhibits three small endothermic and two large exothermic processes. The non‐isothermal kinetics parameters were calculated by the Kissinger's method and Ozawa‐Doyle's method, respectively. The heat of combustion was measured by oxygen bomb calorimetry. The enthalpy of formation, the critical temperature of thermal explosion, the entropy of activation (ΔS≠), the enthalpy of activation (ΔH≠), and the free energy of activation (ΔG≠) were also calculated. Sensitivity tests revealed that 1 is insensitive to mechanical stimuli.

Synthesis, structure, and thermal decomposition of two copper coordination compounds [Cu(DAT)2(PA)2] and [Cu(DAT)2(HTNR)2] with nitrogen rich 1,5-diaminotetrazole (DAT)

Both [Cu(DAT)2(PA)2] (1) and [Cu(DAT)2(HTNR)2] (2) were prepared from 1,5-diaminotetrazole (DAT) and copper trinitrophenol, 1 for picrate (PA) and 2 for styphnate acid (2,4,6-trinitro resorcinol, TNR), and were characterized by elemental analysis, FT-IR spectroscopy, and single crystal X-ray diffraction. The space group of these compounds is P21/c (monoclinic). The lattice parameters are similar [a = 11.405(3) Å, b = 14.867(3) Å, c = 8.099(2) Å for 1 and a = 12.262(3) Å, b = 14.900(3) Å, c = 7.243(2) Å for 2], except the β = 106.257(3)° in 1 and β = 92.989(4)° in 2. Both have extended structures due to hydrogen bonds, but there are some differences because of the ligands induced effect. Differential scanning calorimetry analysis shows that two exothermic processes take place in both complexes, the first peak temperatures are 488.2 K for 1 and 519.2 K for 2. The kinetic parameters of the first exothermic process were studied by using Kissinger’s method and Ozawa’s method, in which the enthalpy of formation (−7346 and −5706 kJ M−1), critical temperature of thermal explosion (475.0 and 515.8 K), entropy of activation (ΔS≠), enthalpy of activation (ΔH≠), and free energy of activation (ΔG≠) were calculated and obtained as −117.25 J K−1 M−1, 140.64 kJ M−1, 196.44 kJ M−1 and −219.1 J K−1 M−1, 383.56 kJ M−1, 495.34 kJ M−1 for 1 and 2, respectively. The sensitivity test results showed that both compounds were sensitive to impact (<5 J) and flame (>20 cm) rather than friction.

Acyl Hydrazine Complexes of Some First Row Transition Metal II Picrates

Acyl Hydrazine Complexes of Some First Row Transition Metal II Picrates

Hydrazine Complexes of Some First Row Transition Metal II Picrates and Picramates

Hydrazine complexes of the compositions M(N/sub 2/H/sub 4/)/sub 2/ (Picrate)/sub 2/ H/sub 2/O (where M = Mn (II), Ni (II), Cu(II) or Zn(II), Co (N/sup 2/H/sup 4/) (Picrate)/sub 2/, Ni(N/sub 2/H/sub 4/)/sub 3/ (Picrate)/sub 2/, Zn(N/sub 2/H/sub 4/)/sub 4/ (Picrate)/sub 2/, and M/sup '/(N/sub 2/H/sub 4/)/sub 2/ (Picramate)/sub 2/ (where M/sup '/ = Mn(II), Fe(II), Co(II), Ni(II), Cu(II) or Zn(II) have been prepared and characterized by analysis, molar conductance, magnetic susceptibility, electronic and infrared spectral data. Molar conductance of the soluble complexes indicate that they are non-electrolytes in THF. Magnetic susceptibility and electronic spectral data suggest that all the complexes are spin-free octahedral except Co(N/sub 2/H/sub 4/) (Picrate)/sub 2/ which is tetrahedral. Infrared spectral studies show that hydrazine behaves as a monodentate ligand in its complexes with metal picramates and as a bidentate bridging ligand in all complexes with metal (II) picrates, except Zn(N/sub 2/H/sub 4)/sub 4/ (Picrate)/sub 2/ where it is monodentate.

A novel compound [Mn(H2O)6](AMTZ)2(PA)2 (AMTZ = 4-amino-3,5-dimethyl-1,2,4-triazole and PA = Picrate) with Extensive hydrogen bonds: Synthesis, structure and thermal characters

The title compound 1, (Mn(H2O)6)(AMTZ)2(PA)2, contains 4-animo-3,5-dimethyl-1,2,4-triazole (AMTZ) and picrate (PA) and was characterized by elemental analysis, FT-IR spectroscopy and Single-Crystal X-ray diffraction. The space group of compound 1 is triclinic P-1(2), with a = 6.797(2) u A, b = 9.800(3) u A, c = 13.197(4) u A, =, =, =. The central Mn 2+ is octahedral and surrounded by two kinds of centrosymmetric molecules, AMTZ and PA. The compound has an extended 3-D supramolecular structure due to water molecules coordinated though hydrogen bonds to the nitrogen and oxygen atoms and the offset face-to- face π ··· π packing. The differential scanning calorimetry (DSC) analysis shows that two exothermic processes take place at 341.4 ◦ C and 473.9 ◦ C. The kinetic parameter of the first exothermic process was studied using Kissinger's method and Ozawa's method. This provided the enthalpy of formation (−3337.7 kJ·mol −1 ), critical temperature of thermal explosion (588.79 K). The entropy of activation (� S / = ), enthalpy of activation (� H / = ), and free energy of activation (� G / = ) were, respectively, -209.78 J·K −1 ·mol −1 , 155.50 kJ·mol −1 and 267.75 kJ·mol −1 . A flame sensitivity test showed that the 50% firing height (h50) was 20 cm.

SORPTION STUDIES OF SOME BIOLOGICALLY IMPORTANT UNIVALENT SALTS USING POLYANILINE PICRATE AS SORBENT

Polyaniline picrate(PANIPI) was synthesized via facile chemical polymerisation route. The as synthesized PANIPI was characterized using UV-Visible, FT-IR and PXRD spectroscopic techniques. Adsorption capacity of the as prepared resin was evaluated from the sorption process. Sorption isotherms were constructed for Langmuir, Freundlich, Redlich-Peterson and Temkin models. The spectral changes after the sorption process were studied using UV-Visible and FT-IR techniques. Facile pH for the adsorption is found to be 5-7. A comparison of ion exchange capacities of PANIPI revealed selectivity of 3:2 for sodium and potassium chloride. The nanosized PANIPI is a potent antimicrobial agent and can be utilized as a biocompatible material.

Energetic Compounds Based on 4‐Amino‐1, 2, 4‐triazole (ATZ) and Picrate (PA): [Zn(H2O)6](PA)2·3H2O and [Zn(ATZ)3](PA)2·2.5H2O]n

AbstractTwo energetic compounds, [Zn(H2O)6](PA)2·3H2O (1) and [Zn(ATZ)3](PA)2·2.5H2O]n (2), were synthesized based on 4‐amino‐1,2,4‐triazole (ATZ) and picrate (PA), and characterized by elemental analysis and Fourier transform infrared (FT‐IR) spectroscopy. The crystallographic data showed that the crystals of 1 and 2 belong to the monoclinic space group P21/n and the triclinic space group P$\bar{1}$, respectively. Furthermore, the ZnII cations are six‐coordinated with six oxygen atoms from crystal water molecules for 1 and six nitrogen atoms from ATZ for 2, and exhibit distorted octahedral configurations. Thermal decomposition mechanisms were determined based on differential scanning calorimeter (DSC) curve corresponding to thermogravimetry‐derivative thermogravimetry (TG‐DTG) curves and kinetic parameters of the first exothermic process were studied by using Kissinger's and Ozawa's method. The energies of the impact sensitivities were 27.8 J for 2 and far greater than 29.4 J for 1. In addition, the experiment found the heats of combustion were –6.53 MJ·kg–1 for 1 and –11.33 MJ·kg–1 for 2 by oxygen bomb calorimeter. Therefore, compound 2 can improve the explosion performance and can maybe regarded as the less toxicity energy additive for the explosives and propellant formulations.

Surgical duodenal ampullectomy in the treatment of ampullary neoplasm: 12 cases experience

Surgical duodenal ampullectomy in the treatment of ampullary neoplasm: 12 cases experience

Abstracts

The multi-ligand coordination compound of [Mn(H2O)6](PA)2·2H2O (1), [Mn(IMI)2(H2O)4](PA)2 (2) and [Mn(IMI)6](PA)2·H2O (3), and a salt of (IMI)(PA)·H2O (4) were synthesized by using imidazole (IMI) and picrate (PA). Furthermore, they were characterized by elemental analysis and FT-IR spectrum. The crystal structures were determined by X-ray single crystal diffraction. The obtained results show the crystals of 1 and 4 belong to orthorhombic, Pccn and Pna21 space groups, and the crystals of 2 and 3 belong to monoclinic, P21/c space groups. The metal Mn(II) cations are six-coordinated and exhibit distorted-octahedral configuration. Under nitrogen atmosphere with a heating rate of 10 K min−1, the thermal decompositions contain two main exothermic stages in the DSC curves corresponding to TG–DTG curves. The non-isothermal kinetics parameters were calculated by the Kissinger’s method and Ozawa’s method, respectively. The energies of combustion, enthalpies of formation, critical temperatures of thermal explosion, entropies of activation (ΔS≠), enthalpies of activation (ΔH≠), and free energies of activation (ΔG≠) were measured and calculated. In the end, the sensitivity properties were also determined with standard methods.

Preparation, crystal structures and thermal decomposition of three energetic manganese compounds and a salt based on imidazole and picrate

The multi-ligand coordination compound of [Mn(H2O)6](PA)2·2H2O (1), [Mn(IMI)2(H2O)4](PA)2 (2) and [Mn(IMI)6](PA)2·H2O (3), and a salt of (IMI)(PA)·H2O (4) were synthesized by using imidazole (IMI) and picrate (PA). Furthermore, they were characterized by elemental analysis and FT-IR spectrum. The crystal structures were determined by X-ray single crystal diffraction. The obtained results show the crystals of 1 and 4 belong to orthorhombic, Pccn and Pna21 space groups, and the crystals of 2 and 3 belong to monoclinic, P21/c space groups. The metal Mn(II) cations are six-coordinated and exhibit distorted-octahedral configuration. Under nitrogen atmosphere with a heating rate of 10Kmin−1, the thermal decompositions contain two main exothermic stages in the DSC curves corresponding to TG–DTG curves. The non-isothermal kinetics parameters were calculated by the Kissinger’s method and Ozawa’s method, respectively. The energies of combustion, enthalpies of formation, critical temperatures of thermal explosion, entropies of activation (ΔS≠), enthalpies of activation (ΔH≠), and free energies of activation (ΔG≠) were measured and calculated. In the end, the sensitivity properties were also determined with standard methods.

Preparation, Crystal Structure, and Thermal Decomposition of the Energetic Compound [Co(IMI)4(PA)](PA) (IMI = Imidazole and PA = Picrate)

AbstractThe novel multi‐ligand coordination compound [Co(IMI)4(PA)](PA) (1) was synthesized by using imidazole (IMI) and picrate (PA) and characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure was determined by X‐ray single crystal diffraction and the crystallographic data showed that the compound crystallizes in the triclinic space group P$\bar{1}$ (α = 8.839(2) Å, b = 13.550(3) Å, c = 13.840(3) Å, α = 68.386(6)°, β = 88.349(9)°, and γ = 87.494(9)°). Furthermore, the CoII ion is six‐coordinated by four nitrogen atoms from four imidazole ligands and two oxygen atoms from a PA group. Its thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetry‐derivative thermogravimetry (TG‐DTG) analysis. The kinetic parameters of the first exothermic process were studied by using Kissinger's and Ozawa's method, respectively. The energy of combustion and the enthalpy of formation were measured and calculated. They showed good combustion performance of the compound. Additionally, the sensitivity properties were determined with standard methods. The results of all these studies showed that [Co(IMI)4(PA)](PA) has potential application as ignition composition.

Two Environmentally Friendly Energetic Compounds, [Mn(AZT)4(H2O)2](PA)2·4H2O and [Co(AZT)2(H2O)4](PA)2, Based on 3‐Azido‐1,2,4‐triazole (AZT) and Picrate (PA)

AbstractTwo multiligand coordination compounds, [Mn(AZT)4(H2O)2](PA)2·4H2O (1) and [Co(AZT)2(H2O)4](PA)2 (2), were synthesized with 3‐azido‐1,2,4‐triazole (AZT) as a ligand and picrate (PA) as a counteranion and characterized by elemental analysis and FTIR spectroscopy. The crystal structures were determined by single‐crystal X‐ray diffraction. The results show that the crystals of 1 and 2 have a triclinic space group (P$\bar {1}$) and orthorhombic space group (Pbca), respectively. Moreover, 1 and 2 have distorted octahedral structures. Their thermal decomposition mechanisms were investigated by differential scanning calorimetry and thermogravimetric analysis. The experimental data showed that the energies of combustion were approximately equal to the energies of combustion of 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX) and 1,3,5,7‐tetranitro‐1,3,5,7‐tetraazocane (HMX). The nonisothermal kinetic parameters were studied by applying the methods of Kissinger and Ozawa. The sensitivity properties showed that 1 and 2 had a higher flame sensitivity than 2,4,6‐trinitrotoluene, RDX, and HMX.

Impacts of different creatinine detection methods on the efficacy of different GFR estimation equations

Objective To investigate the impacts of different serum creatinine detection methods,including Jaffe and enzymatic methods,on the efficacy of different GFR estimation equations in CKD patients in China.Methods rGFR of 176 patients with CKD were determined by dual plasma sample method 99mTc-diethylenetriamine pentaacetic acid (99mTc-DTPA) plasma clearance rate.Serum creatinine was detected with four kinds of creatinine reagents from different manufacturers.Cockcroft-Gault Equation corrected for body surface area (CG/BSA),simplified Modification of Diet in Renal Disease (MDRD) Study equation,IDMS-traceable MDRD equation,CKD epidemiology collaborative research (CKD-EPI) equation and two Chinese simplified MDRD equation (project group equation 1,2) were applied to calculate estimated GFR (eGFR)respectively.eGFR were compared with rGFR for the correlation, deviation, precision and 30％ accuracy.Results The mean rGFR of 176 patients with CKD,was [ 40.70 ( 19.41 -84.35 ) ] ml · min- 1 ·( 1.73 m2 ) -1.For all GFR estimation equations,there were significant differences in eGFR results between enzymatic method and Jaffe method,when analyzed by the Wilcoxon signed-rank test.eGFR results assessed by two enzymatic creatinine detection systems showed no significant difference,while eGFR results analyzed by two Jaffe detection system were significantly different.The intraclass correlation coefficient (ICC) of eGFR and rGFR ranged from 0.879 to 0.923 by Jaffe method,while from 0.925 to 0.946 by enzymatic creatinine method.ICC and Pearson correlation analysis revealed a significant correlation between eGFR and rGFR,and the correlation was better when using enzymatic method.Bland-Altman plots indicated that large deviation occurred in the high value area of GFR using various equations.However,deviation with the enzymatic creatinine method was smaller than that with the Jaffe method. When rGFR ≥ 60 ml · min- 1 ·(1.73 m2) -1,the 30％ accuracy of eGFR using enzymatic creatinine method for all six equations was between 68.3％ and 90.0％,while it was between 41％ and 75％ when using Jaffe method. The 30％ accuracy of eGFR using enzymatic creatinine method was significantly higher than that using picric acid method for these equations except for the project group equation 1.When rGFR ＜60 ml · min -1 · ( 1.73 m2 ) -1,the 30％ accuracy of eGFR using both methods was between 39.7％ -49.1％,40.5％ -52.6％respectively,and the difference of data showed no statistical significance.For the same equation,there was a significant differernce in 30％ accuracy of eGFR between two enzymatic creatinine detection systems,while there was no significant differernce between two Jaffe creatinine detection systems.Conclusions A significant difference was demonstrated in the same GFR evaluation equation using two different creatinine detection methods (Jaffe method and enzymatic method).The correlation between rGFR and eGFR,the degree of deviation,and accuracy of eGFR results assessed by enzymatic creatinine method were better than those by Jaffe method.The eGFR results assessed by different enzymatic detection systems revealed no significant difference. Key words: Glomerular filtration rate; Creatinine; Picrates; Indicators and reagents; Clinical enzyme tests; Algorithms

Accuracy investigation of commonly used creatinine assay systems

Objective To evaluate the accuracy of Cr measurement value from commonly used homogenous detection systems,to investigate the variation among different systems and the corresponding bias of eGFR.Methods According to the CLSI EP14-A2 protocol,commutability of LN24 was validated among 10 enzymatic assays and 1 picrate assay.LN24 included 6 vials of solution with Cr values assigned by IDMS at NIST,and concentrations of Cr for each vial were 68.1,126.9,185.7,244.5,303.2 and 361.9μmol/L LN24 was used to evaluate the accuracy of the included systems and the variation among them,and the assigned values were taken as the target values.eGFR were calculated by MDRD equation using IDMStraced picrate Cr and CKD-EPI equation using enzymatic Cr.Results Commutability was exist among the 11 systems for LN24 detection.Four systems showed bias ＜ 4.4 μmol/L at each level of LN24,two system showed bias ＞4.4 μmol/L at each level of LN24,one system showed a fixed negative bias( -4.2 ±0.7)μ mol/L,the other 4 systems showed diverse bias at different levels.Cr-bias-caused eGFR bias could reach 14.9 ml · min-1 · (1.73 m2) -1 at Cr level of 68.1 μmol/L SD among systems ascended with Cr level (2.6 -6.1 μmol/L) ;CV among systems descended with Cr level(4.0％ - 1.7％ ) ;After the 2 systems with obvious negative bias were removed,SD,CV among systems and eGFR bias decreased obviously.By measuring fresh serum,it was found that Cr bias among enzymatic systems was mostly ＜ 10 μmol/L;that between enzymatic assays and picrate assay was much diffused(from - 15 to 20 μmol/L).When Cr ＜ 100μmol/L,the eGFR difference between result of MDRD equation and that of CKD-EPI equation ranged from - 18 to 40 ml · min-1 (1.73 m2) -1.Conclusions Some enzymatic systems show good accuracy.Difference of Cr value is relatively fixed among enzymatic systems,and comparability can be reached through mathematic way.Un-acceptable difference between picrate assay and enzymatic assays still exists,thus comparability cannot be reached through mathematic way.At low Cr level,bias of Cr and using different equations may lead to significant bias of eGFR.We recommend that clinical laboratory should pay much attention to the accuracy and comparability at low level of Cr,and use uniform equation to calculate eGFR. Key words: Creatinine; Glomerular filtration rate; Kidney diseases; Bias(epidemiology)

A Novel Nitrogen-Rich Cadmium Coordination Compound Based on 1,5-Diaminotetrazole: Synthesis, Structure Investigation, and Thermal Properties

A new coordination compound [Cd(DAT)6](PA)2·(H2O)4 using 1,5-diaminotetrazole (DAT) as a ligand was synthesized and characterized by applying X-ray single crystal diffraction, elemental analysis, and Fourier transform infrared (FT-IR) spectroscopy. The central cadmium(II) cation is coordinated by six N atoms from six DAT molecules to form a six-coordinated and slightly distorted octahedral configuration. The coordination cation is situated between the two picrate (PA) anions whose benzene-ring planes are parallel to each other. All of the molecular units are linked together by intermolecular hydrogen bonds. The thermal decomposition mechanism of the title compound was investigated through differential scanning calorimetry (DSC), thermogravimetric/differential analysis (TG-DTG), and FT-IR analyses. The kinetic parameters of the first exothermic process of this complex were calculated by applying Kissinger’s and Ozawa-Doyle’s methods.

Ajustement du schéma par âge d’entrée en première union : le modèle PICRATE

Nous presentons un nouveau modele qui decrit le schema par âge d’entree dans une nouvelle situation. L’introduction du taux de recrutement rend l’utilisation de ce modele tres simple, en particulier pour simuler l’evolution d’une population au cours du temps. Le modele est defini par trois parametres : a0, l’âge minimal a l’evenement, pmax, la proportion maximale de la population qui connaitra l’evenement, et rmax le taux maximal de recrutement. Ce modele est teste sur l’entree en premier mariage, et est compare au modele de Coale-McNeil. Nous avons applique ce modele au cas de la Zambie, ainsi qu’a divers pays africains ayant des schemas differents. Le modele peut s’appliquer a divers processus, tels que les premiers rapports sexuels, la premiere naissance, le premier emploi, la premiere migration adulte, etc.

Evaluation of matrix effects of reference materials in serum creatinine measurements

Objective To evaluate the trueness of routine systems for serum creatinine measurement and the matrix effects of creafinine reference materials on the systems. Methods The Clinical and Laboratory Standards Institute (CLSI) EP14-A2 protocol was used for the study and an isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method was used as the comparative method. Fory fresh patient specimens, 15 EQA materials, 13 calibrators, two control materials and 8 frozen serum materials were measured by the comparative method and 15 routine systems (7 enzymatic methods and 8 alkaline picrate methods). Matrix effects were assessed by using the EP14-A2 procedure, and the trueness of the evaluated methods were assessed by comparing the results of the 40 fresh patient specimens obtained with the evaluated methods and the comparative method. Results Tweenty-nine of 30 commercial materials showed matrix effects on the alkaline picrate systems, and 13 of the commercial materials showed matrix effects on the enzymatic systems. Fresh frozen serum materials prepared at the National Center for Clinical Laboratories showed no matrix effect on all 15 routine systems. Calibration biases were observed on 8 alkaline picrate systems and some enzymatic methods. Conclusions Matrix effect, calibration bias and nonspecificity in serum creatinine measurements. Continued efforts are needed for improving the trueness and comparability of serum creatinine measurements. Key words: Creatinine; Isotope labeling; Chromatography. liquid; Tandem mass spectrometry; Picrates; Clinical enzyme tests