| The changes of various components in urine are closely related to health and are an important basis for clinical diagnosis.In particular,the change of ion level in urine is usually accompanied by organ disorder,functional disorder,infection and other symptoms,which can reflect the change of human health.The content of calcium in urine is an important index to evaluate calcium metabolism in human body.It has clinical diagnostic significance for early monitoring of urinary stones,diabetes,nephropathy,primary hyperparathyroidism,hypertension,primary aldosteronism,preeclampsia,and many other diseases.Abnormal magnesium ion content in urine is often accompanied by diseases,such as kidney diseases,endocrine system diseases,arthritis and so on.Therefore,the development of analytical methods for ionic components in urine has important research significance for the early diagnosis of a variety of diseases and the home monitoring of patients with chronic diseases.Recently,there are many methods to detect ions in urine,such as titration,colorimetry,fluorescence,inductively coupled plasma-mass spectrometry and so on.These methods can provide reliable and accurate experimental results with huge equipment,complex operation,tedious pretreatment,expensive price,and the professional maintenance are required.At the same time,in the detection of actual urine samples,there are many problems such as interference of various substrates and protein adsorption,these shortcomings limit their application in home detection to a large extent.All-solid-state potentiometric sensing technology as a low energy consumption,simple equipment,easy miniaturization and array,and in the process of detection is not affected by sample color,turbidity,suspended matter,so it is suitable for home detection.Therefore,we constructed a self-calibrated all-solid-state potentiometric sensor based on polystyrene-Au nanocomposites for home detection of ion content in urine.Specific research work includes:1)An all-solid-state potentiometric sensor with self-calibration function was constructed based on polystyrene-Au nanocomposites for home detection of calcium ion in urine.Polystyrene nanoparticles（PS NPs）were prepared as polymer substrates for ion-selective electrodes.Gold nanoparticles（Au NPs）were modified on PS NPs.Calcium ionophore and ion exchanger were swelled into polystyrene-Au nanoparticles（PS-Au NPs）by solvent swelling method in a water-tetrahydrofuran system.Thus,sensing nanocomposites are obtained.The nanocomposites were drop-coated on the screen-printed electrodes and the ion-selective electrode was obtained after drying.Using the same method,the silver ionophore and ion exchanger were swelled into PS-Au NPs to obtain the calibration nanocomposites.By adding calibration channel to subtract the background signal generated during the determination of the actual sample,the interference caused by the background matrix in the actual urine can be eliminated,and the accuracy of the home detection of calcium ion in urine can be improved.Calcium ion concentration was measured by open circuit potential method.In the concentration range of 1.0×10-4～1.0×10-2 mol/L,the sensor obtained a good Nernst response with a slope of26.3±1.7 m V/dec and a detection limit of 4.2×10-5 mol/L.In addition,the sensor has good reproducibility,selectivity and long-term stability.This study provides a new method for rapid home detection of calcium ion in urine.2)An all-solid-state potentiometric sensor with self-calibration was constructed based on polystyrene-Au nanocomposites for detection of magnesium ion in urine.The magnesium sensing nanocomposites was obtained by swelling magnesium ionophore and ion exchanger in PS-Au NPs.The magnesium sensing nanocomposite,calibration material and reference membrane cocktail were added to the screen-printed electrodes to obtain the self-calibrated all-solid-state potentiometric sensor.Magnesium ion concentration was measured by open circuit potential method.The slope of response is 26.7±0.6 m V/dec,which is close to the Nernst response.The linear range is 1.0×10-4～1.0×10-2 mol/L,and the detection limit is 1.3×10-5mol/L.The sensor has fast and stable response to different concentrations of target ions and has a good application prospect.3)An all-solid-state potentiometric sensor with dual-calibration function was constructed based on a 5-channel screen-printed electrode for simultaneous detection of Ca2+and Mg2+in urine.Ca2+sensing channel and Mg2+sensing channel are working channels,and the other three channels are self-calibration channel,p H calibration channel and reference channel.The sensor can calibrate the interference caused by background signal and p H in actual urine detection,improve the accuracy of target ion detection. |
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