Subscribe via Email

Your email:

Follow MeasureNet

MeasureNet Blog

Current Articles | RSS Feed RSS Feed

MeasureNet's Versatile Colorimeter Part 2





Many types of organic molecules will exhibit a VISIBLE fluorescent “emission” when exposed to high energy ULTRA-VIOLET light to create the “excitation”. This spectro-chemical response is due to the interaction of the energetic UV photons with the loosely-held pi-electrons and other “labile” functional groups in aromatic, olefinic, alkaloidal, xanthinoid and poly-cyclic compounds… and there are many important applications for this little-understood, rarely-taught, under-utilized technology. Using the newest in LED technology, the MeasureNet “Colorimeter” has several “excitation” sources available… with the 375nm UV-LED providing the most useful range of responses for relative fluorescence analyses (since it is very close to the classic 366nm long-wavelength UV from a mercury lamp)… although several alternate user-defined Wavelengths are available from a growing list of LED sources. Please inquire for more information!

When used in the “Fluorometer” mode, the detector is situated at a 90° angle from the UV LED Source, to generate TRUE fluorescent “emission” data without potential interference from the “excitation” wavelength. Laboratory exercises for both qualitative comparisons and quantitative analysis of many materials are possible with the MDBC-138 Dual-Beam Colorimeter. Some applications in Organic Chemistry, Analytical Sciences, Biology/Biochemistry, Environmental and Nutritional Science programs, are highlighted here:

 UV-LED Fluorometry for Single-range EMISSION Values:
• “Zap” UV against Chlorophyll from things that Grow… and see what makes it Glow
• The Highlights of Highlighting Markers: How bright is bright?
• Evaluation of Cigarette Second-Hand Smoke: Nicotine for the Masses in your Breathing    Gases?
• Analysis of Alkaloid Materials like Quinine
• Measure Amino Acids in “Energy Drinks”… Are their labels Accurate 
• Check Ground-Water “Plumes” with Fluoresceine… Water-Table extracts will also be green!

MeasureNet's Versatile Colorimeter: Part 1 of 4


Crystal Violet Kinetics Reaction resized 600



A typical colorimeter is usually a simple, single-beam optical system to measure “color” in the VISIBLE Spectrum of light and provide ABSORBANCE data at a single wavelength. These systems can cost $1,000 or more for stand-alone colorimeters that merely provide simple ABS data… unless you consider the MeasureNet Model MDBC-138 true Double-Beam, Multi-Functional “Colorimeter” based on a unique set of LEDs (Light-Emitting Diodes)... for under $500! The MeasureNet “Colorimeter” is actually FOUR (4) instruments in ONE (1) compact and rugged box… and works as a colorimeter (to make Beer’s Law Curves for VISIBLE Wavelengths), a UV fluorometer (to demonstrate fluorescence & quenching in certain organic molecules), a turbidometer (to measure the turbidity of particulate & colloidal suspensions) and a phosphorimeter (to analyze the phosphorescence [“glow”] of specific materials).

This unit can be used as a “simple” Colorimeter to demonstrate Beer’s Law using three (3) high-output VISIBLE Light LEDs at 472nm (BLUE), 525nm (GREEN) and 630nm (RED); which cover over 75% of the classic General Chemistry and Analytical Chemistry Laboratory experiments that teach spectrophotometric measurements. The wavelength coverage of these LEDs allows highly accurate relative measurement of almost all the ROYGBIV Colors. The disposable & unbreakable 10mm pathlength, near-UV plastic cuvettes included with the “Colorimeter” can be used from ~300nm (in the near-UV) to over 1000nm (in the near-IR) for analytical measurements… and come with sealing caps to preserve prepared solutions for future tests. Some of the popular Laboratory experiments for your Academic Lab curriculum programs  Gen Chem, Analytical or Student Research are:

 Red / Blue / Green Colorimetric ABS Data for Beer’s Law plots:
• Test for Mineral IRON in your food… check your Cereals, Breads and more
• Unsaturated FATS can be easily seen… just get a purple Color using some IODINE!
• Evaluation of Nutritional Food Proteins… React it to get a “BLUE” and see what can be seen!
• Consistency of M&M and Skittles Candy Colors: Is the "blue" true blue or “faux” to you!
• Changing “Colors” of some pH Dyes… [H+] makes them look *new* to our eyes!
• General Colorimetric Assay… for ANION (X, PO4, SO4, NO3, NO2, etc) 

The MDBC-138 is a TRUE Double-Beam Optical System… and provides a reference cell to “blank” out the reagents used to create a very stable ABS reading for several Organic Reactions. Data from these Labs can be used to calculate rate constants, equilibrium factors and reaction conditions (for thermal, ionic and electrochemical variables). This is a MUST for making accurate kinetic experiment tests. A few of them from our “Library” include:

 Dual-Beam ABS Data for Kinetic Measurements:
• The Iodine Test for Starches… just Hydrolyze with Amylaze to get a Kinetic Rate
• Perform REDOX “Clock” Reactions 
• pH-based Hydrolysis of p-nitrophenylacetate Ester

All Posts