Detecting Counterfeit Brandies

Esters-targeted colorimetric sensor array for the authenticity discrimination of strong-aroma baijiu with different origins

Baijiu authenticity has been a frequent problem driven by economic interests in recent years, so it is important to discriminate against baijiu with different origins. Herein, we proposed a simple and efficient esters-targeted colorimetric sensor array mediated by hydroxylamine hydrochloride. Esters undergo a nucleophilic addition reaction with hydroxylamine hydrochloride to form hydroxamic acid, which rapidly forms a purplish red ferric hydroxamate under FeCl3·6H2O. Bromophenol blue and rhodamine B enrich the color effects. The array detected 12 esters with a detection limit on the order of 10-5 of most esters and 16 mixed esters with R2 > 0.999 and recoveries close to 100%. Otherwise, for discriminating 34 strong-aroma baijius (SABs), the array has an accuracy of 98% according to the origin, and 95% according to the grades, with a response time of 1 min. This study provides a new strategy for authenticity determination and quality control of baijiu.

Gold nanobipyramid colorimetric sensing array for the differentiation of strong aroma-type baijiu with different geographical origins

It is of great significance to quickly and effectively distinguish strong aroma-type baijiu (SAB) with the largest baijiu market share and the most extensive production regions. Colorimetric sensor arrays based on gold nanobipyramids (AuNBPs) with extraordinary plasmonic properties were constructed for the differentiation of SAB from different geographical origins. The sensing strategy was based on silver deposition on different morphologies of AuNBPs under different reducing conditions containing amino or hydroxyl groups. The deposition process can be effective for distinguishing differences in baijiu due to the chemical interaction between the trace ingredients in baijiu and reductants. The colorimetric sensor arrays were implemented for the response of the main ingredients and further used for the differentiation of SAB from different regions by linear discriminant analysis. The results showed that the sensing strategy had excellent performance in distinguishing SAB from different origins, and provides a promising application strategy for baijiu quality control.

Model verification for population detection of counterfeits

The quality of counterfeit items has increased dramatically, with modern global manufacturing being able to duplicate the materials, construction, and visual features of items. Detection of fraudulent coinage can parallel authentication of food, beverages, and manufactured goods by studying product-inherent features. Counterfeit detection is performed by comparing an Example group with a Questioned group. A model is developed for both groups using standard tests on individual pieces. Coin weight is used here as an illustration. The model should also follow the natural science of the system. In this case, the manufacturing process variation is known and steady, and the underlying distribution is known or can be determined from authentic pieces. The proposed detection method uses testing of many individual pieces, then using reverse-quality-engineering methods to identify possible sources. This strategy looks at the variation between individual pieces to determine the process capability of a machine, assembly line, or plant to create product consistency for a manufacturer. Fraudulent items may be manufactured within specification, but demonstrate a manufacturing process capability different than that of the authentic manufacturer. In this report, we examine the model previously reported and use reconstruction techniques to re-create the evidence set to validate the model, increase model accuracy, and confirm the conclusion previously reached, showing that the Questioned set is likely over 37% non-conforming by weight. In this case, the decision outcome of the analysis was improved by using additional methods not included in the modeling software package originally used.

A Multichannel Fluorescent Tongue for Amyloid-β Aggregates Detection

Attention has been paid to the early diagnosis of Alzheimer's disease, due to the maximum benefit acquired from the early-stage intervention and treatment. However, the sensing techniques primarily depended upon for neuroimaging and immunological assays for the detection of AD biomarkers are expensive, time-consuming and instrument dependent. Here, we developed a multichannel fluorescent tongue consisting of four fluorescent dyes and GO through electrostatic and π-π interaction. The array distinguished multiple aggregation states of 1 µM Aβ40/Aβ42 with 100% prediction accuracy via 10-channel signal outputs, illustrating the rationality of the array design. Screening vital sensor elements for the simplified sensor array and the optimization of sensing system was achieved by machine learning algorithms. Moreover, our sensing tongue was able to detect the aggregation states of Aβ40/Aβ42 in serum, demonstrating the great potential of multichannel array in diagnosing the Alzheimer's diseases.

A novel dual-channel fluorescence sensor array based on the reaction of o-phenylenediamine/3,4-diaminotoluene and pyrocatechol for Baijiu discrimination

An effective method to discriminate Baijiu carries important applications for grade identification and quality control in the Baijiu industry. Herein, we report on a novel and straightforward dual-channel fluorescence sensor array for flavor compounds (FCs) and Chinese Baijiu discrimination. Unit 1 (U1) is the reaction between o-phenylenediamine (OPD) and pyrocatechol (ODHB), and unit 2 (U2) is the reaction between 3,4-diaminotoluene (3,4-DAT) and ODHB. The fluorescent products were changed via FCs in Baijiu relying on the influence of protonation of the amino group on OPD/3,4-DAT and chemical reactions. The array successfully achieves qualitative and quantitative identification of FCs with low detection limits and wide linear ranges. In addition, qualitative identification of 0.7 mmol/L FCs in Baijiu is achieved. Finally, this is applied to discriminate 32 Baijius varieties with different aromas, brands, and grades. The fluorescence sensor array is reliable and straightforward for FCs identification and Baijius discrimination, which is of great significance for authenticity identification in the Baijiu industry.

Amphipolar, Amphiphilic 2,4-diarylpyrano[2,3-b]indoles as Turn-ON Luminophores in Acidic and Basic Media

A versatile amphiphilic pyrano[2,3-b]indole for halochromic turn-ON luminescence in acidic or basic media is accessed by an insertion-coupling-cycloisomerization and adjusting solubilizing and phenolic functionalities. While almost non-emissive in neutral solutions, treatment with acids or bases like trifluoroacetic acid (TFA) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) reveals distinct luminescence at wavelengths of 540 nm or 630 nm in propan-2-ol, respectively. Turn-ON emission can be detected at pH values as mild as pH = 5.31 or 8.70. Quantum yields in propan-2-ol are substantial for protonated (Φf = 0.058) and deprotonated (Φf = 0.059) species. Photometrically, pKa1 of 3.5 and pKa2 of 10.5 were determined in propan-2-ol. With lipophilic polyether sidechains and hydrophilic protonation and deprotonation sites the molecule can be regarded as amphipolar, which results in good solubility properties for different organic solvents. In aqueous media, an organic co-solvent like propan-2-ol (35%) or tetrahydrofuran (25%) is needed, and the solution can be diluted with pure water without precipitation of the compound. At higher concentrations of water, a turbid solution is formed, which indicates the formation of micellar structures or clusters. With dynamic light scattering we could show that these clusters increase in size with increasing water content.

Carbonyl flavor compound-targeted colorimetric sensor array based on silver nitrate and o-phenylenediamine derivatives for the discrimination of Chinese Baijiu

Baijiu is a distilled liquor of great importance in the food industry. Various aroma types, brands, and grades of Baijiu have filled the market; thus, discrimination for quality control is required. Herein, we constructed a novel colorimetric sensor array based on the redox reaction between silver nitrate and o-phenylenediamine or its derivatives for the discrimination of carbonyl flavor compounds (CFCs) and Baijius. The specific colored products were changed by CFCs depending on the influence of silver nanoparticle aggregation and chemical reactions. The array was used to qualitatively and quantitatively identify 21 CFCs with fast response (<14 min), wide linear range (0.025-25 mmol/L), and low detection limits (<60 μmol/L, 29 nmol/L for carboxylic acids). Finally, the array was successfully applied to the discrimination of 56 Baijius. The method proposed in this study is simple, fast, reliable, and has good application potential for the visual determination of Chinese Baijiu.

Machine Learning-Assisted Pattern Recognition of Amyloid Beta Aggregates with Fluorescent Conjugated Polymers and Graphite Oxide Electrostatic Complexes

Five fluorescent positively charged poly(para-aryleneethynylene) (P1-P5) were designed to construct electrostatic complexes C1-C5 with negatively charged graphene oxide (GO). The fluorescence of conjugated polymers was quenched by the quencher GO. Three electrostatic complexes were enough to distinguish between 12 proteins with 100% accuracy. Furthermore, using these sensor arrays, we could identify the levels of Aβ40 and Aβ42 aggregates (monomers, oligomers, and fibrils) via employing machine learning algorithms, making it an attractive strategy for early diagnosis of Alzheimer's disease.

Communication of Bichromophore Emission upon Aggregation - Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines

Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution pattern-tunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors.

Combination of two analytical techniques improves wine classification by Vineyard, Region, and vintage

Three important wine parameters: vineyard, region, and vintage year, were evaluated using fifteen Vitis vinifera L. 'Pinot noir' wines derived from the same scion clone (Pinot noir 667). These wines were produced from two vintage years (2015 and 2016) and eight different regions along the Pacific Coast of the United States. We successfully improved the classification of the selected Pinot noir wines by combining an untargeted 1D ¹H NMR analysis with a targeted peptide based differential sensing array. NMR spectroscopy was used to evaluate the chemical fingerprint of the wines, whereas the peptide-based sensing array is known to mimic the senses of taste, smell, and palate texture by characterizing the phenolic profile. Multivariate and univariate statistical analyses of the combined NMR and differential sensing array dataset classified the genetically identical Pinot noir wines on the basis of distinctive metabolic signatures associated with the region of growth, vineyard, and vintage year.

Sensor Array Based Determination of Edman Degradated Amino Acids Using Poly(p-phenyleneethynylene)s

A cross‐reactive optical sensor array based on poly(p‐phenyleneethynylene)s (PPEs) determines Edman degraded amino acids. We report a sensor array composed of three anionic PPEs P1–P3, and their electrostatic complexes with metal ions (Fe²⁺, Cu²⁺, Co²⁺). We recorded distinct fluorescence intensity response patterns as “fingerprints” of this chemical tongue toward standard phenylthiohydantoin (PTH) amino acids—degradation products of the Edman process. These “fingerprints” were converted into canonical scores by linear discrimination analysis (LDA), which differentiates all of the PTH‐amino acids. This array discriminates PTH‐amino acid residues degraded from an oligopeptide through Edman sequencing. This approach is complementary to chromatography approaches which rely on mass spectrometry; our array offers the advantage of simplicity.