Articles
Shedding light on plant biology by Fourier transform infrared spectroscopy of pollen
Currently, pollen identification is mostly done under a light microscope. FT-IR spectroscopy of pollen grains provides rapid and simple identification of pollen, with the added benefit of providing environmental information.
Quantum cascade laser-based mid-infrared spectrochemical imaging of tissues and biofluids
Mid-infrared spectroscopic imaging is a rapidly emerging technique in biomedical research and clinical diagnostics that takes advantage of the unique molecular fingerprint of cells, tissue and biofluids to provide a rich biochemical image without the need for staining. Spectroscopic analysis allows for the objective classification of biological material at a molecular level.1 This “label free” molecular imaging technique has been applied to histology, cytology, surgical pathology, microbiology and stem cell research, and can be used to detect subtle changes to the genome, proteome and metabolome.2–4
Broadband photon time-of-flight spectroscopy as a prospective tool in biomedicine and industrial process and quality control
The analysis of turbid samples is increasingly important, not least due to their widespread occurrence in natural samples. Dmitry Khoptyar, Sören Johansson, Staffan Strömblad and Stefan Andersson-Engels show “Broadband photon time-of-flight spectroscopy as a prospective tool in biomedicine and industrial process and quality control”. The authors describe their recent development of a broadband spectrometer for evaluation of absorption and scattering spectra of very diverse turbid materials in the visible and close-near infrared (NIR) regions and its application with milk, cheese and paper samples.
Spectral database for postage stamps by means of FT-IR spectroscopy
“Spectral database for postage stamps by means of FT-IR spectroscopy” by Eleonora Imperio, Gabriele Giancane and Ludovico Valli will be of great interest. As well as helping to detect forgeries, FT-IR has been used to create a database which also charts the history of the technology used to create stamps. Quite rightly, they are considered by many to be works of art.
The last furlong (4). Multi-variable regression
Tony (A.M.C.) Davies looks at Multiple Linear Regression (MLR) this issue, as well as expressing his opinions about Principal Components Regression (PCR) and Partial Least-Squares (PLS).
Terahertz spectroscopy
Tony Davies explains “Terahertz Spectroscopy” and describes some new and interesting applications
Review of nanoscale infrared spectroscopy applications to energy related materials
The authors give us a “Review of nanoscale infrared spectroscopy applications to energy related materials”. Fuel cells, photovoltaics and specialised polymers for fracking are all considered.
From lake ecology to biofuels: applications of Fourier transform infrared spectroscopy to algal research
“From lake ecology to biofuels—applications of Fourier transform infrared spectroscopy to algal research” is the topic of Andrew Dean, Jon Pittman and David Sigee. Algae are essential for our continued live on Earth, and FT-IR spectroscopy can increase our understanding of their physiology and biotech potential.
The last furlong (3). Principal component analysis
Tony (A.M.C.) continues down the last furlong of his series of Tony Davies Column articles. This issue, he considers principal component analysis (PCA). Using research recently published in the Journal of Near Infrared Spectroscopy, he explains that PCA is a very useful tool but it will not solve all our problems. Two old articles on PCA, including Tony’s concept of the “Data Cake” have been added to the website, are referenced in Tony’s article and can be freely downloaded by readers.
Novel concepts in infrared spectral imaging as a cancer diagnostic tool
This article describes an application of spectral imaging for the differentiation of tumour and normal cells. The authors also introduce the concept of a spectral barcode, which has had success with some tissues and has potential in others.
Near infrared hyperspectral imaging for foreign body detection and identification in food processing
With continuing food scares around the world, food producers need every tool they can get to prevent contamination of their products at every stage of production. Hyperspectral reflectance imaging in the NIR combined with chemometrics shows much promise for the detection and identification of foreign bodies among food grains.
Fourier transform infrared spectroscopic imaging of live cells
There are a number of approaches, and by combining FT-IR imaging methodology with microfluidics devices, the opportunity to study live cells by FT-IR imaging in controlled environments is now possible.
The last furlong (1). Data compression
Tony (A.M.C.) Davies starts a review of the chemometric ideas that have most excited him over the last 30 years. In this column, he looks at the use of Fourier transformation for data compression. FT can also provide the side benefit of reducing high-frequency noise.
Qualitative and quantitative assessment of acetylated wood using infrared spectroscopic methods and multivariate data analysis
Chemical modification of wood by methods such as acetylation is required to improve characteristics such as photosensitivity and combustibility, and to provide harmonisation of wood properties in order to avoid swelling and shrinking and to improve biodegradability. The authors describe the use of mid and near infrared spectroscopies to monitor chemical changes due to acetylation is described.
Single particle characterisation in biologics: from mid-infrared micro-spectroscopy and mapping to spectral imaging
The presence of “particles” in protein pharmaceuticals (biologics) can cause severe, unwanted effects in the drug. The article describes the use of mid-infrared micro-spectroscopy for the investigation and chemical characterisation of single particles in these biologics.
Variable selection for regression analysis: an up-date on an old problem
Tony (A.M.C.) Davies and Tom Fearn describe an enhancement of the popular partial least squares (PLS) technique, powered partial least squares (PPLS), that has shown significantly better results.
Surface-enhanced infrared spectroscopy
In principle, electromagnetic SEIRS should be as strong as electromagnetic surface-enhanced Raman scattering (SERS) but, in SEIRS, disturbing fluorescence is absent. In order to get maximum IR vibrational signal enhancement for sensing of rare molecules, strong resonant scattering of plasmonic objects is recommended.
What IS and what is NOT chemometrics
Tony Davies makes sure we understand “What IS and what is NOT chemometrics” and why it matters.
Measuring brain activity using functional near infrared spectroscopy: a short review
“Measuring brain activity using functional near infrared spectroscopy: a short review” by Felix Scholkmann and Martin Wolf looks at the various methods for performing fNIRS and some applications that demonstrate why this non-invasive, safely applicable, portable and cost-effective method is now an integral part of the techniques used in neuroscience.
Infrared spectroscopy of nucleoprotein complexes
A. Roque, I. Ponte and P. Suau look at “Infrared spectroscopy of nucleoprotein complexes”. The advantages of IR spectroscopy have allowed them to determine the structure of linker histones and protamines as they interact with DNA. Linker histones are involved with the condensation of the thick chromatin fibre and are believed to have a regulatory role in transcription through the modulation of chromatin higher order structure.