INDICATORS NITROGEN PHOSPHORUS DETECTOR(NPD ELECTRON CAPTURE DETECTOR(ECD) CHP26M2 220209235 GWIJI T PRINT LAYOUT 1. INTRODUCTION 2. DIAGRAM FOR NPD 3. WORKING PRINCIPLES FOR NPD 4. ADVANTAGES OF NPD 5. DISADVANTAGES OF NPD 6. STRUCTURE OF ECD 7. WORKING PRINCIPLES OF ECD 8. ADVANTAGES OF ECD 9. DISADVANTAGES OF ECD 10. COMPARE AND CONTRAST THE PRINPLES OF ECD AND NPD 11. COMPARE AND CONTRAST THE INSTRUMENTATION OF NPD AND ECD 12. CONCLUSSION 13. REFFERENCES CHP26M2 220209235 GWIJI T INTRODUCTION DETECTORS ARE DEVICES USED TO OR DESIGNED TO RESPOND TO A VERY SMALL QUANTITY OF SAMPLE PRESENT IN THE COLUMN GAS.THERE ARE A VARIETY OF INDICATORS IN THEIR VARIOUS TYPES HOWEVER IN THIS SLIDE WE WILL FOCUS MAINLY ON NITROGEN PHOSPHORUS DETECTOR AND ELECTRONIC CAPTURE DETECTOR . CHP26M2 220209235 GWIJI T NPD THE NITROGEN PHOSPHORUS DETECTOR IS A SELECTIVE DETECTOR FOR NITROGEN AND PHOSPHORUS-CONTAINING COMPOUND.ITS DETECTION PRINCIPLE APPEARS TO BE BASED ON THE ELECTRONIC CONDUCTIVITY OF A FLAME IN THE PRESENCE OF AN ALKALI METAL SALTS AND CHANGES THEREIN CAUSED BY NITROGEN OR PHOSPHORUS IN THE COMPOUNDS ENTERING THE DETECTORS. CHP26M2 220209235 GWIJI T ECD AN ELECTRON CAPTURING DETECTOR IS A DEVICE FOR DETECTING ATOMS AND MOLECULES IN A GAS THROUGH THE ATTACHMENT OF ELECTRONS VIA ELECTRON CAPTURE IONOZATION .IT IS USED TO DETECT TRACE AMOUNT OF CHEMICAL COMPOUNDS. CHP26M2 220209235 GWIJI T STRUCTURE OF NPD CHP26M2 220209235 GWIJI T WORKING PRINCIPLE OF NPD USES HYDROGEN/AIR FLAME THROUGH WHICH THIS SAMPLE IS PASSED USES RUBIDIUM/CESIUM BEAD WHICH IS HEATED BY A COIL OVER WHICH THE CARRIER GAS MIXED WITH HYDROGEN PASSES THE HOT BEAD EMITS ELECTRONS BY WHICH ARE COLLECTED AT THE ANODE AND PROVIDES THE BACKROUND CURRENT. WHEN A COMPONENTS THAT CONTAIN N/P EXITS THE COLUMN,THE PARTIALLY COMBUSTED N/P MATERIALS ARE ADSORBED ON THE SURFACE OF THE BEAD. THIS THEN INCREASES THE EMISSION OF ELECTRONS. CHP26M2 220209235 GWIJI T ADVANTAGES OF NPD THE SPECIFIC RESPONSE OF NPD TO NITROGEN AND PHOSPHORUS ,WITH RELATIVELY HIGH SENSITIVITY ,MAKES IT USEFUL FOR ANYLISIS OF PHARMACEUTICALS. IN ENVIRONMENTAL ANALYSIS INVOLVING HERBICIDES DOES NOT DETECT COMMON MOBILE PHASE IMPURITIES OR CARRIER GASES USEFUL FOR DRUG ANALYSIS MORE SENSITIVE TO HETEROCOMPOUNDS CHP26M2 220209235 GWIJI T DISADVANTAGES OF NPD PERFOMANCE DETERIORATES WITH TIME BURNING HYDROGEN VAPOUR CONVERTS ALKALI SILICATE TO AKLALI HYDROXYDE WHICH HAS SIGNIFICANT VAPOUR PRESSURE AND CAUSES LOSS OF CESIUM/RUBIDIUM DESTRUCTIVE DETECTOR LESS SENSITIVE TO ORGANIC COMPOUNDS COMPARED TO FID CHP26M2 220209235 GWIJI T STRUCTURE OF ECD CHP26M2 220209235 GWIJI T WORKING PRINCIPLE A BEAM IS PRODUCED BY THE BETA EMMITER WHEN CARRIER GASPASSES OVER THE EMITTER,THE GAS IONISES PRODUCING ELECTRONS. IN ABSENCE OF COMPOUND IONIZATION OF CARRIER GAS PRODUCES A CONSTANT STANDING CURRENT. WHEN SOLUTE IS ELUTED OUT FROM THE COLUMN ,IT CAPTURES ELECTRONS TOWARDS IT, HENCE CURRENT DECREASES THIS DECREASE GIVES IDEA ABOUT THE CONCENTRATION OF A SOLUTE IN THE SAMPLE CHP26M2 220209235 GWIJI T ADVANTAGES OF ECD DETECTION AND DETERMINATION OF CHLORINATED INSECTICIDES. DOES NOT ALTER THE SAMPLE HIGHLY SENSITIVE TOWARDS COMPOUNDS CONTAINING ELECTRONEGATIVE FUNCTIONAL GROUPS SUCH AS HALOGENS,PEROXIDES,NITRO ETC THE ECD IS SELECTIVE TO ITS RESPONSE IT IS NON DESTRUCTIVE MORE SENSITIVE THAN TCD AND FID CHP26M2 220209235 GWIJI T DISADVANTAGES OF ECD LEAST SENSITIVE TO COMPOUNDSWHOSE MOLECULES HAVE NEGLIGIBLE AFFINITY FOR ELECTRONS. CARRIER GASUSED SHOULD BE OF PURE GAS FORM NON LINEAR RESPONSE UNLESS POTENTIAL ACROSS THE DETECTOR IS PULSED CHP26M2 220209235 GWIJI T COMPARE AND CONTRAST PRINCIPLES OF ECD AND NPD ECD IT IS USED IN ENVIRONMENTAL TESTING MORE SENSITIVE THAN FID FOR MOLECULES CONTAINING ELECTRONEGATIVE FUNCTIONAL GROUPS CHP26M2 220209235 GWIJI T NPD USED IN ANYLIS FOR FOOD,FORENSIC AND ENVIROMENTAL SAMPLES VERY SENSITIVE TO NITROGEN AND PHOSPHORUS CONTAINING MOLECULE COMPARE AND CONTRAST INSTRUMENTATION PRINCIPLES OF ECD AND NPD ECD USES A RADIOACTIVE SOURCE TO SEND CONSTANT CURRENT ELECTRONS ACROSS THE MOBILE PHASE.ONCE A COMPOUND ENTERS THE CURRENT IT BEGIND TO CAPTURE ELECTRONS WHICH DECREASE THE CURRENT. CHP26M2 220209235 GWIJI T NPD BASED ON THE ELECTRONIC CONDUCTIVITY OF AFLAME IN THE PPRESENCE OF AN ALKALI METAL SALTS AND CHANGES THEREIN CAUSED BY NITROGEN OR PHOSPHORUS IN THE COMPOUND ENTERING THR DETECTORS.THEN THIS INCREASES THE EMISSION OF ELECTRONS. CONCLUSION NPD IS A SELECTIVE DETECTOR FOR NITROGEN AND PHOSPHORUS HENCE IT IS MORE SENSITIVE TOWARDS THEM.ITS BASED ON ELECTRONIOC CONDUCTIVITY IN THE PRSENCE OF AN ALKALI EARTH METAL SALT AND IT IS MOSTLY USED IN ANALYSIS OF SAMPLES ECD USES ELECTRON CAPTURE IONISATION TO CAPTURE ATOMS AND TO DETECT THE AMOUNT OF CHEMICAL COMPOUND.IT USES RADIOACTIVE SOURCE TO SEND CONSTANT CURRENT OF ELECTRONS ACROSS THE MOBILE.IT IS HIGHLY SENSITIVE TOWARDS ELECTRONEGATIVE FUNCTIONAL GROUPS AND IS USED FOR ENVIRONMENTAL TESTING CHP26M2 220209235 GWIJI T REFFERENCES SLIDEPLAYER.COM INSTRUMENTATION—GC-ECD-BERKELEY HTTP://EN.M.WIKIPEDIA.ORG/WIKI/INSTRUMENTATION SLIDETODOC.COM COMMUNITY.ASDLIB.ORG SLIDESHARECDN.COM CHROMEDIA.ORG SHIMADZU.COM LABTRAINING.COM RESEARCHGATE.NET CHP26M2 220209235 GWIJI T
