spectrophotometer 2.pdf

SPECTROPHOTOMETER ✍ BY :FARIS YOUSIF👨‍🔬  WHAT IS SPECTROPHOTOMETER 🤔 ASPECTROPHOTOMETER IS AN INSTRUMENT WHICH IS USED TO MEASURE THE INTENSITY OF ELECTROMAGNETIC RADIATION AT DIFFERENT WAVELENGTHS. SPECTROPHOTOMETERS ARE GENERALLY USED FOR THE MEASUREMENT OF TRANSMITTANCE OR REFLECTANCE...

SPECTROPHOTOMETER ✍ BY :FARIS YOUSIF👨‍🔬  WHAT IS SPECTROPHOTOMETER 🤔 ASPECTROPHOTOMETER IS AN INSTRUMENT WHICH IS USED TO MEASURE THE INTENSITY OF ELECTROMAGNETIC RADIATION AT DIFFERENT WAVELENGTHS. SPECTROPHOTOMETERS ARE GENERALLY USED FOR THE MEASUREMENT OF TRANSMITTANCE OR REFLECTANCE OF SOLUTIONS, TRANSPARENT OR OPAQUE SOLIDS SUCH AS POLISHED GASES OR GLASS. WHT IS UV- VIS 😎☠ UV-VIS SPECTROPHOTOMETER IS AN ANALYTICAL TECHNIQUE THAT MEASURES THE AMOUNT OF DISCRETE WAVELENGTHS OF UV OR VISIBLE LIGHT THAT ABSORBED BY OR TRANSMITTED THROUGH A SAMPLE.  THE WATER BATH OF THE SPECTROPHOTOMETER: A SMALL WATER BATH IS BUILT IN HERE WITH A SPACE FOR THE CUVETTE HOLDER. THE ONLY PURPOSE IS TO CARRY ENZYME REACTION AT 37 C EG AST, ALT, CK. THES TAKE INCUBATION OF 5 MINUTE AT 37 WITHOUT ANY COLOR DEVELOPMENT. IS CALLED REACTION RATE ANALYSIS. WAVELENGTH IS UV AT 340 NM  WAVELENGTHS OF VARIOUS TYPES OF RADIATION Type of radiation Gamma <.0 1 X-Rays 0.1--10 ULTRAVIOLET < 380 Visible 380 -- 750 INFRARED > 750 Radio- waves > 25 ×10⁷  WHAT ARE THE DIFFERENT TYPES OF SPECTROPHOTOMETERS? 🤔😯 1. UV SPECTROPHOTOMETER 2. UV- VIS- SPECTROPHOMETER 3. ATOMIC ABSORPTION SPECTROPHOTOMETER  🙄 TYPES 1. A SINGLE BEAM SPECTROPHOTOMETER MEASURES THE RELATIVE LIGHT INTENSITY OF THE BEAM BEFORE AND AFTER THE TEST SAMPLE IS INTRODUCED. 2. A DOUBLE BEAM SPECTROPHOTOMETER COMPARES THE LIGHT INTENSITY BETWEEN 2 LIGHT PATHS, ONE PATH CONTAINING THE REFERENCE SAMPLE AND THE OTHER THE TEST SAMPLE.  THE BASIC SPECTROPHOTOMETER INSTRUMENT CONSISTS 🙋 1. LIGHT SOURCE 2. DIGITAL DISPLAY 3. MONOCHROMATOR 4. WAVELENGTH SECTOR TO TRANSMIT A SELECTED WAVELENGTH 5. COLLIMATOR 6. PHOTOELECTRIC DETECTOR AND A CUVETTE TO PLACE A SAMPLE.  WHAT IS ABSORBANCE🤔🧐 ABSORBANCE (A), ALSO KNOWN AS OPTICAL DENSITY (OD), IS THE QUANTITY OF LIGHT ABSORBED BY A SOLUTION. TRANSMITTANCE T IS THE QUANTITY OF LIGHT THAT COMES OUT. HOW DOES A SPECTROPHOTOMETER WORK?🤔☹ 1. THE LIGHT SOURCE PROVIDES ALL THE WAVELENGTHS OF VISIBLE LIGHT WHILE ALSO PROVIDING WAVELENGTHS IN ULTRAVIOLET AND INFRA RED RANGE. 2. THE FILTERS AND DIFFRACTION GRATING SEPARATE THE LIGHT INTO ITS COMPONENT WAVELENGTHS SO THAT VERY SMALL RANGE OF WAVELENGTH CAN BE DIRECTED THROUGH THE SAMPLE. 3- THE SAMPLE COMPARTMENT PERMITS THE ENTRY OF NO STRAY LIGHT WHILE AT THE SAME TIME WITHOUT BLOCKING ANY LIGHT FROM THE SURCE 4- THE PHOTO DETECTOR CONVERTS THE AMOUNT OF LIGHT WHICH IT HAD RECEIVED INTO A CURRENT WHICH IS THEN SENT TO THE SIGNAL PROCESSOR WHICH IS THE SOUL OF THE MACHINE. 5- THE SIGNAL PROCESSOR CONVERTS THE SIMPLE CURRENT IT RECEIVES INTO ABSORBANCE, TRANSMITTANCE AND CONCENTRATION VALUES WHICH ARE THEN SENT TO THE DISPLAY. HOW TO USE A SPECTROPHOTOMETER? 🙄🤔 SPECTROPHOTOMETER IS USED TO DETERMINE ABSORBENCY AT CERTAIN WAVELENGTHS OF A SOLUTION. THIS CAN BE USED TO DETERMINE THE CONCENTRATION OF A SOLUTION OR TO FIND AN UNKNOWN SUBSTANCE. USE 👨‍🔬 1. CLEAN OUT THE CUVETTE IN THE MACHINE MAKING SURE THAT THROUGHOUT THE EXPERIMENT, WE FACE IT THE SAME WAY INTO THE MACHINE EACH TIME. ANY FINGERPRINTS OR DIRT ON THE CUVETTE CAN AFFECT THE RESULTS OF THE EXPERIMENT. SO, IT IS ALWAYS ESSENTIAL TO WEAR GLOVES.  2- THEN, ADD THE SOLUTE WHICH WOULD BE THE BLANK FOR THE EXPERIMENT. IT IS IMPORTANT NOT TO ADD WATER TO THE BLANK SO THAT IT WON’T AFFECT THE ACCURACY OF THE RESULTS.  3- AS A NEXT STEP, THE SPECTROPHOTOMETER IS SET TO THE DESIRED WAVELENGTH. INSERT THE BLANK CUVETTE, MAKING SURE THAT THE ARROW IS ALIGNED EACH TIME. THEN PRESS THE “SET ZERO” TO CALIBRATE THE SPECTROPHOTOMETER FOR THAT WAVE LENGTH. 4- NOW, INTRODUCE THE SOLUTION IN ORDER TO CALCULATE ITS ABSORBENCY. EACH TIME WE CHANGE THE WAVELENGTH, IT IS IMPORTANT TO CHANGE BLANK FOR THAT WAVELENGTH.  THE MEASUREMENT PRINCIPLE USED BY A SPECTROPHOTOMETER 🧑‍🔬 FIRST THE INTENSITY OF THE MEASUREMENT LIGHT BEAM, I0, IS MEASURED WITHOUT THE SAMPLE SET. THEN THE SAMPLE IS SET IN THE PATH OF THE MEASUREMENT LIGHT BEAM, AND THE INTENSITY OF THE LIGHT BEAM AFTER IT PASSES THROUGH THE SAMPLE, IT, IS MEASURED..LIGHT SOURCE 💡 THE DESIRABLE PROPERTIES OF A LIGHT SOURCE ARE AS FOLLOWS: A) BRIGHTNESS ACROSS A WIDE WAVELENGTH RANGE B) STABILITY OVER TIME C) A LONG SERVICE LIFE D) LOW COST  THANKS 🙈