Front face synchronous fluorescence as a tool for the quality assurance of Greek milk

This research focuses on implementing the low cost and rapid front face synchronous fluorescence (SyFS) in order to ensure the quality assurance of Greek milk. Specifically, samples originated from the Greek domestic production of goat, sheep, cow, as well as foreign cow milk samples and adulterated cow milk samples. SyFS spectra were acquired in the excitation area of 250–500 nm with (Δλ)= 100 nm. Greek and foreign cow milk samples were differentiated based on intensity variations at wavelengths 350–515 nm, 540–579 nm, and 580–600 nm. The emissions at these wavelength positions correspond to tryptophan, vitamin A, and riboflavin. The supervised model with 94 samples exhibited p-value = 7,98E-11, RMSEE= 0,29171, RMSEcv= 0,29284 and RMSEP= 0,98013, AUROC for Greek samples= 0,61 and AUROC for foreign= 0,85. We differentiated milk samples according to the animal type with PCA and OPLS-DA models of 107 samples exhibiting RMSEE= 0,225842, RMSEcv= 0,228054 and RMSEP= 0,518635, AUROC for sheep samples= 0,99, AUROC for goat samples= 0,98 and AUROC for cow samples= 0,96. In fact, the emission band 350–591 nm characterized sheep milk and corresponds to aminoacids and fatty acids, cow milk was related to the 350–600 nm emission band related to the b-carotene and to the goat milk the emission bands 350–505 nm and 520–600 nm were attributed to tryptophan, NADH and Rivoflabin. Finally, we investigated whether SyFS coupled with chemometrics may provide preliminary evidence on adulterated cow milk samples. All models were validated with permutation testing, p-values and ROC curves.     

Simultaneous chemical fingerprint and quantitative analysis of Rhizoma Smilacis Glabrae by accelerated solvent extraction and high‐performance liquid chromatography with tandem mass spectrometry

Rhizoma Smilacis Glabrae (RSG) is a well‐known herbal medicine with the homology of medicine and food. In this study, simultaneous chemical fingerprint and quantitative analysis of the bioactive flavonoid components of RSG were developed using accelerated solvent extraction and high‐performance liquid chromatography coupled with ion trap tandem mass spectrometry. The operational parameters of accelerated solvent extraction including extraction solvent, extraction temperature, static extraction time, solid‐to‐liquid ratio, and extraction cycles were optimized. Hierarchical cluster analysis, similarity analysis, and principal component analysis were performed to evaluate the similarity and variation of the samples collected from several provinces in China. Subsequently, high‐performance liquid chromatography fingerprints were established for the discrimination of 16 batches of RSG samples, and the major six flavonoids, namely, toxifolin, neoastilbin, astilbin, neoisoastilbin, isoastilbin, and engeletin were then quantitatively determined. The calibration curves for all the six analytes showed good linearity (r² > 0.999), and the limits of detection and quantification were less than 0.10 and 0.27 μg·mL^?1, respectively. Therefore, the proposed extraction and determination methods were proved to be robust and reliable for the quality control of RSG.     

Discrimination of crude and processed rhubarb products using a chemometric approach based on ultra fast liquid chromatography with ion trap/time‐of‐flight mass spectrometry

Crude rhubarb subjected to different processing procedures will produce different therapeutic effects that are possibly due to processing‐induced variation in chemical composition. In this study, a chemometric approach based on ultra fast liquid chromatography with ion trap/time‐of‐flight mass spectrometry was established to systematically investigate the chemical variations of rhubarb induced by different processing methods. The approach was validated based on pooled quality‐control samples from two perspectives: the individual properties of variables and the bulk properties of samples. Orthogonal partial least squares discriminant analysis was introduced to compare the differences between crude and processed rhubarb products. A total of 20 significantly different markers were screened out and unambiguously/tentatively characterized. This research proved that a chemometric method based on ultra fast liquid chromatography with ion trap/time‐of‐flight mass spectrometry can comprehensively analyze the chemical variation of herbal medicine and provide evidence for a deeper understanding of the pharmacological activities of processed rhubarb products.     

Chemometrics for comprehensive analysis of nucleobases,nucleosides, and nucleotides in Siraitiae Fructus by hydrophilic interaction ultra high performance liquid chromatography coupled with triple‐quadrupole linear ion‐trap tandem mass spectrometry

A rapid and sensitive hydrophilic interaction ultra high performance liquid chromatography coupled with triple‐quadrupole linear ion‐trap tandem mass spectrometry method was validated for the simultaneous determination of 20 nucleobases, nucleosides, and nucleotides (within 3.5 min), and then was employed to test the functional food of Luo‐Han‐Guo samples. The analysis showed that the Luo‐Han‐Guo was rich in guanosine and uridine, but contained trace levels of the other target compounds. Chemometrics methods were employed to identify 40 batches of Luo‐Han‐Guo samples from different cultivated forms, regions and varieties. Unsupervised hierarchical cluster analysis and principal component analysis were used to classify Luo‐Han‐Guo samples based on the level of the 20 target compounds, and the supervised learning method of counter propagation artificial neural network was utilized to further separate clusters and validate the established model. As a result, the samples could be clustered into three primary groups, in which correlation with cultivated varieties was observed. The present strategy could be applied to the investigation of other edible plants containing nucleobases, nucleosides, or nucleotides.     

Data fusion methodologies for food and beverage authentication and quality assessment – A review

The ever increasing interest of consumers for safety, authenticity and quality of food commodities has driven the attention towards the analytical techniques used for analyzing these commodities. In recent years, rapid and reliable sensor, spectroscopic and chromatographic techniques have emerged that, together with multivariate and multiway chemometrics, have improved the whole control process by reducing the time of analysis and providing more informative results. In this progression of more and better information, the combination (fusion) of outputs of different instrumental techniques has emerged as a means for increasing the reliability of classification or prediction of foodstuff specifications as compared to using a single analytical technique. Although promising results have been obtained in food and beverage authentication and quality assessment, the combination of data from several techniques is not straightforward and represents an important challenge for chemometricians. This review provides a general overview of data fusion strategies that have been used in the field of food and beverage authentication and quality assessment.     

Two low-cost digital camera-based platforms for quantitative creatinine analysis in urine

In clinical analysis creatinine is a routine biomarker for the assessment of renal and muscular dysfunctions. Although several techniques have been proposed for a fast and accurate quantification of creatinine in human serum or urine, most of them require expensive or complex apparatus, advanced sample preparation or skilled operators. To circumvent these issues, we propose two home-made platforms based on a CD Spectroscope (CDS) and Computer Screen Photo-assisted Technique (CSPT) for the rapid assessment of creatinine level in human urine. Both systems display a linear range (r² = 0.9967 and 0.9972, respectively) from 160 μmol L⁻¹ to 1.6 mmol L⁻¹ for standard creatinine solutions (n = 15) with respective detection limits of 89 μmol L⁻¹ and 111 μmol L⁻¹. Good repeatability was observed for intra-day (1.7–2.9%) and inter-day (3.6–6.5%) measurements evaluated on three consecutive days. The performance of CDS and CSPT was also validated in real human urine samples (n = 26) using capillary electrophoresis data as reference. Corresponding Partial Least-Squares (PLS) regression models provided for mean relative errors below 10% in creatinine quantification.     

Anisotropy resolved multidimensional emission spectroscopy (ARMES): A new tool for protein analysis

Structural analysis of proteins using the emission of intrinsic fluorophores is complicated by spectral overlap. Anisotropy resolved multidimensional emission spectroscopy (ARMES) overcame the overlap problem by the use of anisotropy, with chemometric analysis, to better resolve emission from different fluorophores. Total synchronous fluorescence scan (TSFS) provided information about all the fluorophores that contributed to emission while anisotropy provided information about the environment of each fluorophore. Here the utility of ARMES was demonstrated via study of the chemical and thermal denaturation of human serum albumin (HSA).     

An Expeditious Method Combining Multi-Components Determination and Fingerprinting Based on Ultra Performance Liquid Chromatography-Photo Diode Array-Tandem Mass Spectrometry and Chemometrics: Application for Authentication and Quality Evaluation of Cornus Officinalis Sieb. et Zucc

Selective and efficient analytical methods for authentication and quality evaluation of herbal medicines are significant and necessary. An expeditious method combining multi-components determination and fingerprinting based on ultra-performance liquid chromatography-photo diode array-tandem mass spectrometry (UPLC-PDA -MS/MS) and chemometrics for authentication and quality evaluation of Cornus Officinalis Sieb. et Zucc was developed. Tandem mass spectrometer operating in multiple reaction monitoring (MRM) was used for determination of three characteristic constituents (morroniside, sweroside, and loganin) in C. Officinalis. Meanwhile, UPLC fingerprint of C. Officinalis was established and the data set was submitted for classification to a suite of chemometrics method. Combing main biologically active components content level and chemometrics analysis, the effects of cultivation area, harvesting, and storage time on the quality of C. Officinalis were investigated. The study reveals that multi-components determination coupled with fingerprinting could be applied for authentication and quality evaluation of C. Officinalis which is accurate, efficient, and reliable.     

Automated peak width measurements for targeted analysis of ion mobility unresolved species

Peak broadening in ion mobility (IM) is a relatively predictable process and abnormally broad peaks can be indicative of the presence of unresolved species. Here, we introduce a new ion mobility peak fitting (IM_FIT) software package for automated and systematic determination of traveling wave ion mobility (TWIM) unresolved species. To identify IM unresolved species, the IM_FIT software generates a trend line by plotting ions' mobility peak widths as a function of their arrival times. Utilizing user-defined thresholds, IM_FIT allows for automated and rapid detection of ions that deviate from the peak width trend line. To demonstrate the advantages of IM_FIT for automated detection of IM unresolved species, IM-mass spectrometry (IM-MS) data from a sample mixture containing polypropylene glycol and multiple peptides were analyzed. A total of 14 out of the 34 observed singly-charged IM peaks above 5% relative abundance (i.e., signal-to-noise ratios above ∼200) were tagged as potentially co-eluting ions by IM_FIT. Subsequently, the 14 IM peaks tagged as potentially unresolved (presumably, peaks corresponding to co-eluting compounds), were further analyzed by automated IM deconvolution (AIMD), liquid chromatography-IM-MS (LC-IM-MS), and/or ultra-high resolution mass spectrometry. Using the aforementioned techniques, more than 85% of the tagged IM peaks (12 out of 14) were confirmed to contain co-eluting ions. As an additional new finding, IM_FIT facilitated the discovery of an unexpected sequence-scrambled y-type fragment ion.