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Hydrogen peroxide is a dominating coreactant of most luminol electrochemiluminescence (ECL) studies though it is unstable and sensitive to many metal ions. Tripropylamine is an eminent coreactant of tris(2,2'-bipyridine)ruthenium ECL. In comparison with H2O2, tripropylamine is much more stable. In this study, tripropylamine has been exploited as a new coreactant of luminol ECL for the first time. The emission spectrum reveals that the ECL peak was aroused by excited 3-aminophthalate. Under optimized conditions, a biphasic linear relationship is obtained between the ECL intensities and luminol concentrations in the presence of 10 mM tripropylamine over the range of 1.0 × 10−11 −1.0 × 10−7 M and 1.0 × 10−7 −1.0 × 10−4 M with a detection limit of 6.9 × 10−12 M. The detection of tripropylamine showed a linear relationship between ECL intensities and tripropylamine concentrations in the range of 1.0 × 10−6 to 1.0 × 10−2 M with a detection limit of 7.7 × 10−7 M. Compared to luminol-H2O2 ECL, luminol-tripropylamine ECL system displays not only high stability but also high sensitivity. Hence, it shows great potential in many fields including immunoassay or non-immunoassay diagnostic, clinical, pharmaceutical, environmental and food analysis in the future.

Creatinine is an important biomarker in clinical diagnosis and biomonitoring programs as well as urinary metabolomic/metabonomics research. Current methods are either nonselective, time consuming or require heavy and expensive instruments. In this study, chemiluminescence of creatinine with hydrogen peroxide has been reported for the first time, and its chemiluminescence is remarkably enhanced in the presence of cobalt ions. By utilizing these phenomena, we have developed a sensitive and selective chemiluminescence method for creatinine determination by coupling with flow injection analysis. The calibration curve is linear in the range of 1×10(-7)-3×10(-5)mol/L with a limit of detection (S/N=3) of 7.2×10(-8)mol/L, which is adequate for detecting creatinine in the clinically accepted range. The relative standard deviation for seven measurements of 3×10(-5)mol/L creatinine is 1.2%. The chemiluminescence method was then utilized to detect creatinine in human urine samples after simple dilution with water. It takes less than 1min each measurement and the recoveries for spiked urine samples were 100-103%. The interference study demonstrates that some common species in urine, such as amino acids, ascorbic acid and creatine, have negligible effects on creatinine detection. The present method does not use expensive instruments, enzymes and separation technique. This method has the advantages of sensitivity, selectivity, simplicity, rapidity, and low cost. It holds great promise for basic or comprehensive metabolic panel, drug screening, anti-dopping, and urinary metabolomic/metabonomics research.

Chemiluminescence (CL) is a light-emitting phenomenon as a result of chemical reactions. Luminol and lucigenin are typical CL luminophores, and hydrogen peroxide is typical coreactant. It is an important analytical technique because of its inherent features, such as high sensitivity, wide dynamic range, fast detection, simple equipment, and low instrumentation costs because no external light source or optics is needed. It has been extensively used for immunoassays, DNA detection, enzymatic biosensors, forensic bloodstain detection, pharmaceutical analysis, metal ion determination, imaging and so on. To improve performance of CL analysis and broaden the applications of CL, it is of great importance to develop new CL systems. Herein, we present some new CL systems such as artemisinin/luminol, thiourea dioxide/luminol, N-hydroxyphthalimide/luminol, hydroxylamine-O-sulfonic acid/luminol, allantoin/ lucigenin and creatinine/H2O2 systems. We will also demonstrate their applications in forensic bloodstain detection, enzyme detection, metal ions detection, and so on [1-7]. Acknowledgment We are grateful for financial support from the National Key Research and Development Program of China (No. 2016YFA0201300), National Natural Science Foundation of China (Nos. 21874126,21675148), the Chinese Academy of Sciences (CAS)-the Academy of Sciences for the Developing World (TWAS), President’s Fellowship Program, and the CAS President's International Fellowship Initiative (PIFI) project. References 1. Wenyue Gao, Chao Wang, Kateryna Muzyka, Shimeles Addisu Kitte, Jianping Li, Wei Zhang and Guobao Xu*. Artemisinin-luminol chemiluminescence for forensic bloodstain detection using smart phone as detector. Chem., 2017, 89 (11), 6160–6165. 2. Wenyue Gao, Wenjing Qi, Jianping Lai, Liming Qi, Saadat Majeed and Guobao Xu*. Thiourea dioxide as unique eco-friendly coreactant of luminol chemiluminescence for sensitive detection of luminol, thiourea dioxide, and cobalt ions. Chem. Commun., 2015, 51(9), 1620–1623. 3. Muhammad Saqib, Liming Qi, Pan Hui, Anaclet Nsabimana, Mohamed Ibrahim Halawa, Wei Zhang,* Guobao Xu*. Development of luminol-N-hydroxyphthalimide chemiluminescence system for highly selective and sensitive detection of superoxide dismutase, uric acid and Co2+. Biosens. Bioelectron., 2018, 99, 519-524. 4. Muhammad Saqib, Baohua Lou, Mohamed Ibrahim Halawa, Shimeles Addisu Kitte, Zhongyuan Liu, Guobao Xu* Chemiluminescence of lucigenin-allantoin and its application for the detection of allantoin. Chem., 2017, 89(3), 1863-1869. 5. Muhammad Saqib, Wenyue Gao, Jianping Lai, Liming Qi, Saadat Majeed, Muhammad Rehan Hasan Shah Gilani, Guobao Xu*. Hydroxylamine-O-sulfonic acid as an efficient coreactant of luminol chemiluminescence for selective and sensitive detection. Chem. Commun., 2015, 51, 6536–6539. 6. Yixiang Lan, Fan Yuan, Tadesse Haile Fereja, Chao Wang, Baohua Lou*, Jianping Li*, and Guobao Xu*. Chemiluminescence of Lucigenin/Riboflavin and Its Application for Selective and Sensitive Dopamine Detection. Anal. Chem., 2019, 91(3), 2135-2139. 7. Saima Hanif, Peter John*, Wenyue Gao, Muhammad Saqib, Liming Qi, Guobao Xu*. Chemiluminescence of creatinine/H2O2/Co2+ and its application for selective creatinine detection. Biosens. Bioelectron., 2016, 75, 347-351.

Wireless electrochemiluminescence system based on the wireless energy transmission technique has been demonstrated for the first time. It has a disposable transmitter and a coiled energy receptor. The coiled energy receptor is smartly used as the electrode. The wireless electrochemiluminescence system has been used to detect hydrogen peroxide with good sensitivity, featuring advantages of easy manipulation, low cost, and small size. The handy and cheap wireless electrochemiluminescence device can use laptops as a power supply. It is promising for the development of portable or disposable electrochemiluminescence devices for various applications (e.g., such as point of care testing, field analysis, scientific research, and chemical education). These advantages enable one to integrate many wireless electrochemiluminescence minidevices with screen printing coiled electrode arrays in microwell plates and charge-coupled devices (CCD) cameras to develop electrochemiluminescence high-throughput screening systems with broad applications in clinical analysis, drug screening, and biomolecular interaction studies.

The quenching of electrochemiluminescence by single-walled carbon nanohorn has been demonstrated for the first time. Moreover, a sensitive, label-free, and signal-on electrochemiluminescence ATP aptasensor was developed using single-walled carbon nanohorn as both quencher and scaffold.

Alkanethiols generally form self-assembled monolayers on gold electrodes and the electrochemical reduction of aromatic diazonium salts is a popular method for the covalent modification of carbon. Based on the reaction of alkanethiol with aldehyde groups covalently bound on carbon surface by the electrochemical reduction of aromatic diazonium salts, a new strategy for the modification of carbon electrodes with alkanethiols has been developed. The modification of carbon surface with aldehyde groups is achieved by the electrochemical reduction of aromatic diazonium salts in situ electrogenerated from a nitro precursor, p-nitrophenylaldehyde, in the presence of nitrous acid. By this way, in situ electrogenerated p-aminophenyl aldehyde from p-nitrophenylaldehyde immediately reacts with nitrous acid, effectively minimizing the side reaction of amine groups and aldehyde groups. The as-prepared alkanethiol-modified glassy carbon electrode was further used to make biomembrane-like films by casting didodecyldimethylammonium bromide on its surface. The biomembrane-like films enable the direct electrochemistry of immobilized myoglobin for the detection of hydrogen peroxide. The response is linear over the range of 1–600 μM with a detection limit of 0.3 μM.