[Baseline correction of Raman spectrum based on piecewise linear fitting].

The baseline drifts of Raman spectra occur in many types of instrumental measurements. It is an important part and a routine step to correct the baseline drift for the data preprocessing. In the present work, the limitations of the baseline correction method based on polynomial fitting were highlighted and a modified polynomial fitting method, i.

[Analysis of astaxanthin in Phaffia rhodozyma using laser tweezers raman spectroscopy].

In the present paper, a method was established based on laser tweezer Raman spectroscopy for rapid quantification of astaxanthin in Phaffia rhodozyma cells. First, the Raman spectra of astaxanthin standard solution with different concentrations were determined and the standard curve for astaxanthin with the peak intensity at 1 520 cm- was plotted; And then the Phaffia yeast cells cultivated in different nitrogen source and carbon source medium were divided into two parts, one for the detection of Raman spectra, and the other for the determination of ultraviolet visible spectrophotometry; Finally the relationship between the two methods was analyzed. The correlation coefficient of standard curve for astaxanthin is 0.

[Analysis of pigments from Rhodotorula glutinis by Raman spectroscopy and thin layer chromatography].

The pigments from Rhodotorula glutinis were separated by using thin layer chromatography, and the result showed that Rhodotorula glutinis cells could synthesize at least three kinds of pigments, which were beta-carotene, torulene, and torularhodin. The Raman spectra based on the three pigments were acquired, and original spectra were preprocessed by background elimination, baseline correction, and three-point-smoothing, then the averaged spectra from different pigments were investigated, and the result indicated that Raman shift which represents C-C bond was different, and the wave number of beta-carotene demonstrated the largest deviation, finally torulene and torularhodin in Rhodotorula glutinis had more content than beta-carotene. Quantitative analysis of Raman peak height ratio revealed that peak height ratio of pigments showed little difference, which could be used as parameters for further research on living cells, providing reference content of pigments.

[Identification of Cortex Phellodendri by Fourier-transform infrared spectroscopy and principal component analysis].

Fourier transform infrared spectrometer was used to collect infrared spectra of Cortex Phellodendri from six different regions. Original spectra were preprocessed by carrying out appropriate baseline correction and five-points smoothing, and the averaged spectra of Cortex Phellodendri from the six origins were analyzed. As a result, the averaged spectra looked quite similar.

[Raman tweezers-based analysis of carotenoid synthesis in Rhodotorula glutinis].

Carotenoid synthesis in Rhodotorula glutinis was investigated with Raman tweezers in order to find the effect of nitrogen and carbon resource on carotenoid yield. The cells in fermentation terminus were harvested, and then divided into two parts, one for UV analysis, the other for Raman tweezers detection. Original spectra were preprocessed by carrying out background elimination and baseline correction, and the averaged spectra of cells cultivated in different fermentation medium were analyzed qualitatively.

[Using Raman spectroscopy to analyze apoptosis of gastric cancer cells induced by cisplatin].

Apoptosis of gastric cancer cells induced by cisplatin was investigated using laser Raman spectroscopy. Gastric cancer cells (SGC7901) were treated with 10 microg x mL(-1) cisplatin for 24, 48 and 72 hours, then were divided into two parts, one for fluorescence staining, the other for collection of Raman spectra by means of scanning. The acquired spectra were then preprocessed by background elimination, smoothing, normalization, baseline correction, and peak fitting.