M. Nassar

Multiple reflection ATR is ideal for detecting miniscule levels of components in solutions. If one component is volatile, trace analysis can be simplified by allowing the volatile liquids to evaporate. A multiple reflection ATR with a small sampling area is advantageous in cases where limited sample is available, as it allows additional concentration of the residue. 

This note explores the use of a multiple reflection diamond ATR accessory to detect and identify the minor chemical variability between different types of nail polish remover. 

Harrick Diamond ConcentratIR2™ (see Figure 1), which supplies seven reflections from the sample, was installed and aligned in a commercial FTIR spectrometer. Spectra were collected at 4 cm

 resolution and signal averaged over 64 scans. Three nail polish removers — the original, nourishing, and strengthening formulations from the same brand — were analyzed. A single drop of each type was placed on the diamond ATR crystal. Infrared spectra were collected over a range of 4000 cm

  periodically until the solvent, acetone, had fully evaporated. 

Figure 1: ConcentratIR2â¢ Multiple Reflection ATR.			

Many of the new peaks that emerge are present in all three samples. Only a few bands, in the 1600 cm

  region, as shown in Figure 2, are unique to any given sample. This is in good accordance with listed ingredients which indicates only a few unique substances in the analytes. Unique peaks include a H–C–H alkane bend at 1500 cm

 , probably from tocopheryl acetate, an ingredient found only in the "nourishing" formula. Characteristic peaks are also observed at 1225 cm

  which are likely due to panthenol, another element particular to the nourishing formulation. Some other ingredients specific to one formula, such as citric acid (nourishing) and benzophenone-1 (strengthening) are present in quantities too small to be detected. Use of additional reflections or greater concentration of the sample might make these apparent. 

Figure 2: ATR spectra of original (black), strengthening (red), and nourishing (blue) nail polish removers.			

The ConcentratIR2™ can be used effectively to measure trace differences in residues of complex solutions. Since the crystal is also only 4-mm in diameter, only single drops of the sample are required, making it extremely useful in situations where only limited quantities of sample area available. 

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				tel. (800) 248-3847, fax (914) 747-7209

Articles

Multiple reflection ATR is ideal for detecting miniscule levels of components in solutions. If one component is volatile, trace analysis can be simplified by allowing the volatile liquids to evaporate.

An Infrared Investigation of Nail Polish Remover Using Multiple Reflection Diamond ATR

Clays, like kaolinite and smectite, are hygroscopic and it is well known that the adsorbed water can be driven off at elevated temperatures. At very low temperatures, in addition to the typical band narrowing and shifting, changes in the O-H bond vibrational modes of clays have also been observed. This note explores changes in kaolin spectrum at temperatures down to -23 °C. 

The spectra were taken using a Praying Mantis™ diffuse reflectance accessory equipped with its high temperature reaction chamber and cooling cartridge (Figure 1). The cooling cartridge was connected to a Julabo F25-ED refrigerating/heating circulator and the sample was examined at temperatures from ambient to -23 °C. 8 min after achieving thermal equilibrium, infrared spectra from the 4000 cm

  were recorded using a commercial FT-IR spectrometer. Spectra were signal averaged over 32 scans at an 8 cm

Figure 1: The Praying Mantis diffuse reflectance accessory, equipped with its high temperature reaction chamber and cooling cartridge.			

Figure 2 shows a portion of the spectrum of kaolin recorded at two different temperatures. Cooling results in the emergence of two peaks at 2960 cm

  in addition to a peak shift in the band at 3434 cm

. Band shifts and emergence of bands are typically associated with changes in temperature. Note that the low temperature here was limited by the chiller which was designed for operation down to -28 °C. Low temperatures, down to -95 °C, could be achieved by this method using an appropriate chiller and coolant.  

Figure 2: Diffuse reflectance spectrum of kaolin, measured at ambient temperature (blue) and at -23 Â°C (red).			

The low temperatures achieved were sufficient to observe minor changes in the kaolin spectrum but were not sufficient to induce previously reported O-H vibrational changes. The Praying Mantis with its cooling cartridge and an appropriate chiller can be used effectively for moderately low temperature experiments. 

Special thanks to Christine Anderson, JULABO. 

tel. (914) 747-7202, fax (914) 747-7209  

Clays, like kaolinite and smectite, are hygroscopic and it is well known that the adsorbed water can be driven off at elevated temperatures. At very low temperatures, in addition to the typical band narrowing and shifting, changes in the O-H bond vibrational modes of clays have also been observed.

M. Nassar

Articles

An Infrared Investigation of Nail Polish Remover Using Multiple Reflection Diamond ATR

Low Temperature Analysis of Kaolin Clay Using Diffuse Reflectance