Transmission FTIR derivative spectroscopy for estimation of furosemide in raw material and tablet dosage form

A Fourier transform infrared derivative spectroscopy(FTIR-DS)method has been developed for determining furosemide(FUR)in pharmaceutical solid dosage form.The method involves the extraction of FUR from tablets with N,N-dimethylformamide by sonication and direct measurement in liquid phase mode using a reduced path length cell.In general,the spectra were measured in transmission mode and the equipment was configured to collect a spectrum at 4 cm^(-1) resolution and a 13 s collection time(10 scans co-added).The spectra were collected between 1400 cm^(-1) and 450 cm^(-1).Derivative spectroscopy was used for data processing and quantitative measurement using the peak area of the second order spectrum of the major spectral band found at 1165 cm^(-1)(SO_(2) stretching of FUR)with baseline correction.The method fulfilled most validation requirements in the 2 mg/mL and 20 mg/mL range,with a 0.9998 coefficient of determination obtained by simple calibration model,and a general coefficient of variation <2%.The mean recovery for the proposed assay method resulted within the(100±3)%over the 80%–120% range of the target concentration.The results agree with a pharmacopoeial method and,therefore,could be considered interchangeable.

First-order Derivative Spectrophotometry for the Determination of Vitamin C in Medicament

A novel method for the determination of vitamin C（Vc） is proposed in this article. After the reaction with Folin-Ciocalteau reagent at ambient temperature, Vc solution was scanned at 750--1100 nm, and its first-order derivative spectrum were obtained from the original spectrum. The values of derivative selected at 995 nm were used for determination. It was proved that Vc could quickly react with Folin-Ciocalteau reagent within 5 min and the product was quite stable for a long time. The conditions required for this method is not very complicated, its precision and accuracy are similar to those of the iodometric titration described in Chinese Pharmacopoeia, and the limit of detection is 0.312 μg/mL. The determination of the results of vitamin C tablet, pill, and injection demonstrates that this method has wide pharmaceutical applications.

Applications of Raman spectroscopy in two-dimensional materials

At present,two-dimensional(2D)materials have shown great application potential in numerous fields based on their physical chemical and electronic properties.Raman spectroscopy and de-rivative techniques are effective tools for characterizing 2D materials.Raman spectroscopy conveys lots of knowledge on 2D materials,including layer number,doping type,strain and interlayer coupling.This review summarized advanced applications of Raman spectroscopy in 2D materials.The challenges and possible applied directions of Raman spectroscopy to 2D materials are discussed in detail.

Analysis and discrimination of ten different sponges by multi-step infrared spectroscopy

In this study,a convenient method using multi-step infrared spectroscopy,including Fourier transform infrared spectroscopy（FT-IR）,second derivative infrared spectroscopy（SD-IR） and two-dimensional correlation infrared spectroscopy（2DCOS-IR）,was employed to analyze and discriminate ten marine sponges from two classes collected from the Xisha Islands in the South China Sea.Each sponge had an exclusive macroscopic fingerprint.From the IR spectra,it was noted that the main ingredient of calcareous sponges was calcium carbonate,but that of demosponges was proteins.For sponges from the same genus or having highly similar chemical profile（IR spectral profile）,SD-IR and 2DCOS-IR were applied to successfully reveal the tiny differences.It was demonstrated that the multi-step infrared spectroscopy was a feasible and objective approach for marine sponge identification.

Communication Chain-foldability effect on coaggregation Evidence derived from time-resolved fluorescence spectroscopy

Very recently,we have proposed that all culprit molecules of arteriosclerosis mightpossess a common and measurable inherent property,namely,a coaggregating ten-dency.Extensive kinetic measurements of these tendencies in terms of △CAgC valueshave led to a new and surprising observation,i.e.,the cholesteryl ester with a longsaturated 18-carbon chain(CE-18)actually has a much smaller tendency towardcoaggregation than that of the ester with a“short”8-carbon chain(CE-8).Thisstate of affairs has been coined as the“chain-foldability effect”,i.e.,the 18-carbon