Foodstuff Samples Research Articles

Simultaneous analysis of several plasticizer classes in different matrices by on-line turbulent flow chromatography-LC-MS/MS.

The development of methodologies for the determination of plasticizers is essential for assessing the environmental and human impact resulting from the use of plastics. A fast analytical method with on-line purification based on turbulent flow chromatography (TFC) coupled to tandem mass spectrometry (MS-MS) has been developed for the analysis of ten phthalates, four alternative plasticizers (including adipates and citrates), and 20 organophosphate esters (OPEs). The method has been validated for the determination of plasticizers across different matrices. Analytical parameters showed acceptable recoveries ranging between 50 and 125%, RSDs lower than 20%, and mLODs of 0.001-2.08ngg-1 wet weight (ww), 0.002-0.30ngg-1, and 0.001-0.93ngm-3 for foodstuffs, face masks, and ambient air, respectively. These methodologies were applied to foodstuff samples purchased in grocery stores, reusable and self-filtering masks, and indoor air measured in different locations. Plasticizers were detected in all the analyzed samples, with values up to 22.0μgg-1 ww, 6.78μgg-1, and 572ngm-3 for foodstuffs, face masks, and indoor air, respectively. The contribution of each family to the total plasticizer content varied between 1.3 and 87%, 0.5 and 98%, and 0.5 and 65% for phthalates, alternative plasticizers, and OPEs, respectively. These findings highlighted the need for analytical methodologies capable of simultaneously assessing a wide number of plasticizers with minimal extractionsteps. This capability is crucial in order to obtain more conclusive insights into the impact of these pollutants on both the environment and human health, arising from different sources of exposure such as foodstuffs, plastic materials, and atmospheric air.

Quantitative risk assessment of radiocesium associated with Japanese foods imported into the United Kingdom.

Damage to a nuclear power station resulted in radioactive contamination of certain areas of Japan in 2011. Legislation was put in place in Europe to establish controls on the import of certain types of food and feed, including a limit of 100 radioactive decays (becquerel, Bq) per second of radiocesium per kg. This legislation was retained in the United Kingdom after leaving the EU and then reviewed in 2021. A quantitative risk assessment was developed to estimate the radiological risk to public health from consuming Japanese food imported into the United Kingdom should the maximum level on radiocesium be removed. Although Japanese monitoring data indicated occurrences when products exceeded the 100Bq per kg limit, these were found to be rare; a total of 1485 occurrences (0.0013%) of all measured foodstuff samples (>1 million) within the scope of this assessment had radiocesium activity concentrations that exceeded 100Bq per kg. Using the recorded occurrence and level of radiocesium measured, and the current pattern and volume of food imported from Japan, there was an estimated excess risk of fatal cancer of around one in a million per year, categorized as negligible compared to the baseline 2018-2020 UK cancer fatality rate of around 1 in 4. On the basis of the described assessment and the estimated small additional risk, Great Britain lifted import controls related to radioactivity present in food from Japan. A number of recommendations to address data gaps and approaches in this assessment are made, particularly how we can improve modeling UK dietary habits for specialist foods.

The Application of Hydrogen Sulfide Fluorescent Probe in Food Preservation, Detection and Evaluation.

This work primarily reviewed the response mechanism of fluorescent probes for H2S detection in foodstuffs in recent years, as well as the methodologies employed for detecting foodstuffs. Firstly, the significance of studying H2S gas as an important signaling molecule is introduced. Subsequently, a review of the response mechanism of the scientific community on how to detect H2S in foodstuffs samples by fluorescent probe technology is carried out. Secondly, the methods commonly used for detecting foodstuffs samples are discussed, including the test strip method and the spiking recovery methods. Nevertheless, despite the significant advancements in this field, there remain some research gaps. Finally, the article identifies the remaining issues that require further attention in current research and proposes avenues for future investigation. More importantly, this work identifies the current limitations of research in this field and proposes future applications of fluorescent probes for H2S in assessing food freshness and determining food spoilage. Therefore, this review will provide robust technical support for the protection of consumer health and the advancement of the sustainable development of the food industry and also put forward some new ideas and suggestions for future research.

Occurrence of bisphenol analogues and their conjugated metabolites in foodstuff

Bisphenol analogues (BPs) are prevalent in diverse foodstuff samples worldwide. However, the occurrence of conjugated bisphenol A (BPA) and bisphenol S (BPS) metabolites in foodstuff remains poorly understood. This study analyzed eight BPs, and four conjugated BPA and BPS metabolites, in three animal-derived foodstuff and five plant-derived foodstuff samples from China. Results showed that fish foodstuff (9.7 ng/g ww) contained the highest mean concentration of BPA, followed by rice (5.1 ng/g ww) and beans foodstuff (3.6 ng/g ww). BPA-sulfate had higher mean concentrations than BPA-glucuronide in different foodstuff categories, except that in eggs foodstuff (p < 0.05). Compared with other foodstuff items, fish (3.4 ng/g ww) and vegetable (1.6 ng/g ww) foodstuff samples exhibited comparatively higher mean concentrations of BPS. Mean concentrations of BPS-sulfate were consistently higher than BPS-glucuronide in vegetables, meats, and fish foodstuff (p < 0.05). BPA contributed the major total dietary intake (DI) of BPs, with the mean DI of 435 ng/kg bw/day for women and 374 ng/kg bw/day for men, respectively. To our knowledge, this study is the first to investigate the occurrence of conjugated BPA and BPS metabolites in foodstuff, which enhances our comprehension of the origins of these conjugated metabolites in the human body.

Antibiotic resistance of Bacillus species isolated in foodstuff samples that were collected in Babylon (Iraq)

A total of 164 food samples were collected from various supermarkets and farmers in various areas of Babylon, were placed in plastic containers, and were transported to the laboratory. The isolation of Bacillus species was performed by culture in blood agar, chromogenic agar, and the absence of growth on McConkey agar, by staining with Gram stain, and through molecular identification of the species’ 16SrRNA gene and sequencing. The antibiotic susceptibility test used eight types of antibiotics. The undertaken sequencing identified the Bacillus isolates to belong to the follow¬ing species: B. subtilis (2), B. cereus (6), B. thuringiensis (1), B. anthracis (1), and B. spizizenii (1). The susceptibility test of the six B. cereus isolates revealed that 5 (83.3%), 4 (66.6%), 3 (50%), 2 (33.3%), 2 (33.3%), 2 (33.3%), 1 (16.6%), and 0 (0%) were resistant to rifampicin, clindamycin, erythromycin, tetracycline, trimethoprim, nitrofurantoin, gentamicin, and ciprofloxacin, while the respective resistance numbers for the two isolates of B. subtilis were 2 (100%), 2 (100%), 2 (100%), 0 (0%), 1 (50%), 0 (0%), 0 (0%), and 0 (0%). One isolate of B. thuringiensis presented resistance to erythromycin, erythromycin, trimethoprim, and rifampicin, while one isolate of B. anthracis was found to be resistant to gentamicin, erythromycin, nitrofurantoin, and rifampicin. The B. spizizenii isolate was resistant to all antibiotics except gentamicin and trimethoprim.

Susceptibility to antibiotics and virulence profiling of Proteus mirabilis among foodstuff

Proteus mirabilis is a genus of bacteria that can cause foodborne diseases. We collected 100 canned food samples from local supermarkets in Hillah (Iraq), including juice (23%), milk products (22%), beef (20%), fish (14%), milk (12%), and tomato paste (9%) samples. We subsequently characterized some virulence factors of P. mirabilis found in these foodstuff, including biofilm formation, protease activity, motility, haemolysis, adhesion, urease production, lipase pro¬duction, and antibiotic susceptibility. In a total of 32 foodstuff samples of positive culture, P. mirabilis was isolated in 15 (46.8%), including 3 juice samples, 4 milk product samples, 2 beef samples, 1 fish sample, 3 milk samples, and 2 tomato paste samples. All isolates exhibited swarming motility (100%) and urease production (100%), while none of the isolates was found to produce haemolysin. The results of the antibiotic susceptibility test revealed a higher re¬sistance against ampicillin (86.6%).

Determination of chromium in foodstuffs by using novel adsorbent in vortex assisted-dispersive solid phase micro-extraction method: An application of multivariate techniques

A new graft copolymer composed of polystyrene and polylinoleic acid (PLinas) with the sodium salt of iminodiacetate (Ida) was synthesized and used as an adsorbent. The vortex-assisted dispersive solid-phase micro-extraction (VA-dSPµE) method was used for the extraction and pre-concentration of chromium. Multivariate methodologies, such as factorial design and 3D surface plots, were applied for screening and optimizing effective extraction parameters. The influence of diverse analytical parameters, such as pH, sample volume, and interfering ions, on the extraction of chromium was studied. The calibration standard curve exhibited a linear range from 0.01 to 0.50 μg L−1. The relative standard deviation and limit of detection were found to be 1.65 % and 0.003 μg L−1, respectively. Extraction recoveries were found in the range of 96 to 99 % by using certified reference materials (CRMs). The adsorbent capacity of PLinas-Ida was found to be 112 mg g−1. The VA-dSPµE method demonstrated its effectiveness in the pre-concentration and determination of chromium within samples of foodstuffs by graphite furnace-atomic absorption spectrometry (GF-AAS).

Efficient pre-concentration of trace levels of the synthetic food dye in foodstuff samples through an adsorption extraction technique using a novel inorganic–organic nanocomposite

In the present study, a maleic acid-functionalized exfoliated graphite/calcium hydroxide (MA-EG/Ca(OH)2) was constructed and employed as a novel inorganic–organic nanocomposite for an efficient dispersive solid-phase microextraction (DSPME) of trace levels of sunset yellow (SY), a synthetic food dye in foodstuff samples before UV–Vis determination. To identify and characterize of the sorbent, various analytical techniques were utilized, including, Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET) analyses. The MA-EG/Ca(OH)2 exhibited a specific surface area of 40.35 m2 g−1 and adsorption capacity of 46.72 mg g−1 towards SY. Central composite design (CCD) in conjunction with a response surface methodology (RSM)-based ANOVA analysis was applied for evaluation and optimization of effective factors including pH (X1), sorbent mass (X2), contact time (X3), and elution volume (X4). According to the results, the optimum values were pH: 6.0, sorbent mass: 12 mg, contact time: 12 min, and elution volume: 0.18 µL. Under theses optimized conditions, DSPME/UV–Vis determination demonstrated a linear range of 50–4800 ng mL−1, a limit of detection (LOD) of 12.45 ng mL−1, and a limit of quantification (LOQ) of 41.49 ng mL−1 (n = 3). The relative standard deviation (RSD) at low concentration level (50–500 ng mL−1) of SY was 4.58 %. Recovery values in different concentration levels were in the range of 96.4–102.9 %. Overall, the proposed method showed the superior features, including ease of synthesizing the sorbent, acceptable LOD and LOQ values, remarkable sensitivity, a wide operational range, good reusability (up to five cycles), environmentally friendly as well as cost-effectiveness, that make it a promising candidate for the analysis of SY in foodstuff samples.

Determination of Chromium Mineral in Foodstuffs in Indonesia using INAA Method

The concentration of the element chromium (Cr) was determined in 76 types of food ingredients from four provinces in Indonesia. The element Cr is one of the essential elements needed by the human body for physiological processes. Although the amount needed for Cr is relatively small, this mineral is very important for the insulin hormone to function properly. Chromium deficiency can result in decreased insulin sensitivity, glucose intolerance and an increased risk of diabetes. The Cr element was determined using the Instrumental Neutron Activation Analysis (INAA) method in the GA. Siwabessy Multipurpose Research Reactor. The reactor which is located in the Puspiptek area has a thermal neutron flux of around 5.47 x 1013 n.cm-2s-1 . Bombardment Cr-50 in foodstuffs samples by thermal neutrons will produce Cr-51 through the n, nuclear reaction. The radiosotope Cr-51. The radiosotope Cr-51 which is the result of thermal neutron activation has a half-life of 27.7 days. The single energy peak of the Cr- 51 gamma-ray can be observed at 320.08 keV. The results showed that cassava leaves, melinjo leaves, watercress, sweet potato leaves, papaya leaves, ipomoea aquatica, kenikir, pumpkin leaves, spinach and mushrooms are foodstuffs rich in Cr compared to other foodstuffs. Foodstuffs from Pandeglang Regency-Banten Province have relatively higher Cr concentrations than other three locations.The concentration of Cr in foodstuffs ranges from 0.039 to 5.244 µg/g.

Preparation and application of KCC-1@ZIF-8 for the solid extraction of tetracycline with high adsorption capacity.

In this study, three different materials were prepared: dendritic fiber-type silica (KCC-1), zeolitic imidazolate framework-8 (ZIF-8), and a new composite material called KCC-1@ZIF-8. These materials were synthesized using microemulsion, stirring, and coating methods, respectively. The properties of the materials were characterized using various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), TGA and X-ray diffraction (XRD). The results showed that KCC-1@ZIF-8 exhibited a significant increase in the BET surface area and pore size compared to the individual components KCC-1 and ZIF-8. These improved properties of the composite material were beneficial for enhancing the adsorption capacity. The effects of initial concentrations, solution pH and reaction time on the adsorption capacity were investigated. The adsorption kinetics and isothermal data of ZIF-8 and KCC-1@ZIF-8 fitted well with pseudo-second-order and Langmuir isotherm models. The results of adsorption thermodynamics show that the adsorption process is spontaneous and endothermic. KCC-1@ZIF-8 exhibited a very high adsorption capacity (751.46 mg g-1) at an initial TC hydrochloride concentration of 80 mg L-1 in an aqueous solution at 301.15 K, and the value was higher than that of ZIF-8 (549.80 mg g-1) under the same conditions. KCC-1 exhibited a relatively lower capacity (37.860 mg g-1). Based on these findings, KCC-1@ZIF-8 was considered a promising adsorbent for the treatment of wastewater contaminated with TC hydrochloride. Additionally, the composite material, when combined with high-performance liquid chromatography (HPLC), could be used as a solid-phase extraction adsorbent for the adsorption of TC hydrochloride in animal foodstuff samples. The calibration curves showed a linear range of 20-500 μg L-1, and the recovery rate ranged from 85.216% to 90.717%. No one has made adsorbents with this new structure before, and KCC-1@ZIF-8 possessed excellent adsorption properties, which make it a potential candidate for environmental remediation and analytical applications involving TC hydrochloride.

قياس مستويات تراكيز غاز الرادون ومحتويات الراديوم في بعض عينات المواد الغذائية التي تم تجميعها من األسواق الفلسطينية

The objective of this study is to assess the concentrations of radon and radium contents in some household food samples available in the Palestinian market. A total of 56 samples are analyzed using Solid State Nuclear Track Detectors (SSNTDs) named CR-39 detectors. By evaluating the radon concentrations in these food items, the study attempts to provide valuable information on potential radiation exposure and health risks associated with their consumption. The average values of 222Rn and 226Ra concentrations in Legumes, Spices, Medical plants, and Seeds samples were 419.0 Bq/m3 and 35.0 Bq/kg; 400.0 Bq/m3 and 33.0 Bq/kg; 259.0 Bq/m3 and 30.5 Bq/kg and 400.0 Bq/m3 and 30.0 Bq/kg, respectively. And therefore, it is determined that the consumption of foodstuffs in the study area poses no notable threat to public health from radon exposure.

Novel probe based on rhodamine B and quinoline as a naked-eye colorimetric probe for dual detection of nickel and hypochlorite ions

This work demonstrates the design and straightforward syntheses of several novel probe-based on rhodamine B and 2-mercaptoquinoline-3-carbaldehydes as a naked-eye colorimetric probe, indicating a sensitive and selective recognition towards nickel (II) with a limit of detection 0.30 μmol L−1 (0.02 mg L−1). Further, by employing the oxidation property of hypochlorite (OCl−), this novel probe parallelly has been deployed to detect hypochlorite in laboratory conditions with a limit of detection of 0.19 μmol mL−1 and in living cells. Regarded to negligible cell toxicity toward mammalian cells, this probe has the potential to determine these analytes in in-vivo investigation and foodstuff samples.

Discovery and occurrence of organophosphorothioate esters in food contact plastics and foodstuffs from South China: Dietary intake assessment

A recent study revealed the presence of non-pesticide organothiophosphate esters (OTPEs) — precursors to organophosphate esters (OPEs) contaminants — in river water. Since OPEs have demonstrated adverse reproductive outcomes in humans, this accentuates the urgency to explore the prevalence of non-pesticide OTPEs in other potential human exposure matrices. In this study, a nontarget screening method based on high-resolution mass spectrometry was used to identify OTPEs in food contact plastic (FCP) samples collected from South China. O,O,O-triphenyl phosphorothioate (TPhPt) and O,O,O-tris(2,4-di-tert-butylphenyl) phosphorothioate (AO168 = S) were unequivocally identified (Level 1), while O,O-di(di-butylphenyl) O-methyl phosphorothioate (BDBPMPt) was tentatively identified (Level 2b, indicating probable structure based on diagnostic evidence). Among n = 70 FCP samples, AO168 = S emerged with the highest detection frequency and median concentration of 74 % and 111 ng/g, respectively. Significant Pearson correlations were observed in log-transformed peak areas of AO168 = S and TPhPt in FCPs with their respective oxons, respectively. Occurrences of AO168 = S and TPhPt were further investigated in n = 100 foodstuff samples using a market basket method. AO168 = S and TPhPt exhibited detection frequencies of 43 % and 44 % in all food items with mean concentrations of 2.17 ng/g wet weight (ww) (range: <0.53–67.8 ng/g ww) and 0.112 ng/g ww (range: <0.006–2.39 ng/g ww), respectively. The highest mean concentrations for AO168 = S and TPhPt were found in vegetables (4.62 ng/g ww) and oil (3.00 ng/g ww), respectively. The median estimated daily intakes (EDIs) of AO168 = S and TPhPt via diet were calculated as 10.4 and 1.51 ng/kg body weight/day, respectively. For AO168 = S, only meat and vegetables contributed to the median EDI, whereas for TPhPt, oil was identified as the principal contributor to the median EDI. This study for the first time evaluated human exposure to OTPEs via diet, providing new insights to overall human exposure to OPEs.

High-resolution mass spectrometry-based screening and dietary intake assessment of organophosphate esters in foodstuffs from South China

Organophosphate esters (OPEs) are a group of emerging contaminants with widespread environmental occurrence, yet research on their occurrence in foodstuffs is limited. We collected 100 foodstuff samples in South China using a market basket method, and analyzed food extracts for the presence of OPEs and organophosphite antioxidants (OPAs) by suspect and nontarget screening through high-resolution mass spectrometry. Our analysis resulted in the identification of 30 OPEs, comprised of 25 OPEs with a confidence level (CL) of 1 (unequivocal identification using standards) and five OPEs with CL = 2b (probable structure based on diagnostic evidence). Interestingly, 11 of these identified OPEs had not been previously reported in food. No OPA was identified. The occurrence of identified OPEs within the food samples was further investigated. The highest median concentration of OPEs in all food samples was reached by tris(2-chloroisopropyl) phosphate (TCPP) (1.55 ng/g ww, range < 0.74–12.0 ng/g wet weight (ww)). Cereals demonstrated the highest median concentration of the cumulative 30 OPEs. Tris(2-chloroethyl) phosphate (TCEP), TCPP, and triethyl phosphate (TEP) predominantly contributed to OPEs contamination in most food categories. Eight OPEs, namely TEP, tris(2-ethylhexyl) phosphate (TEHP), TCEP, triphenyl phosphate (TPhP), 2-ethylhexyl diphenyl phosphate (EHDPP), bis(2-ethylhexyl) phenyl phosphate (BEHPP), resorcinol bis(diphenyl phosphate) (RDP), and methyl diphenyl phosphate (MDPP) exhibited significantly higher concentrations in the processed group as compared to non-processed group, suggesting that food processing may result in contamination of these OPEs. The median sum of estimated dietary intake (ΣEDI) of all OPEs was determined to be 161 ng/kg body weight/day. Cereals (38.5 %) and vegetables (23.5 %) were the predominant food categories contributing to ΣEDI, and TEP (29.0 %), TCEP (20.2 %), and TCPP (18.3 %) were three major OPEs contributing to ΣEDI. This study for the first time offered a comprehensive overview of OPE species and revealed their occurrence in foodstuffs from South China.

A 3,5-dinitropyridin-2yl Substituted Flavonol-based Fluorescent Probe for Rapid Detection of H2S in Water, Foodstuff Samples and Living Cells.

A novel flavonol-based fluorescent probe, Fla-DNT, has been synthesized for the rapid and specific detection of H2S. Fla-DNT exhibits excellent selectivity and anti-interference properties, a short response time (4min), large Stokes shift (138nm), and low detection limit (1.357 µM). Upon exposure to H2S, Fla-DNT displays a remarkable increase in fluorescence intensity at 542nm. Meanwhile, the recognizing site of H2S was predicted through Electrostatic potential and ADCH charges calculations, while the sensing mechanism of H2S was determined via HRMS analysis and DFT calculation. More importantly, the probe owes multiple applications, such as a recovery rate ranging from 92.00 to 102.10% for detecting H2S in water samples, and it can be fabricated into fluorescent strips to track H2S production during food spoilage by tracking color changes, thereby enabling real-time monitoring of food freshness. The bioimaging experiments demonstrate the capability of Fla-DNT to detect both endogenous and exogenous H2S in living cells. These results provide a reliable method and idea for H2S detection in complex environments.

Multiple Applications of a Novel Fluorescence Probe with Large Stokes Shift and Sensitivity for Rapid H2S Detection.

Herein, a novel fluorescence probe Fla-DNP based on flavonol has been designed and synthesized for rapid, specific detection of H2S. With the addition of H2S, Fla-DNP triggered thiolysis and released Fla displaying the "turn-on" fluorescence response at 566nm, which is consistent with the reaction site predicted by calculating Electrostatic potential and ADCH charges. As an easily available H2S probe, Fla-DNP has the advantages of high selectivity, anti-interference, low detection limit (0.834μM), short response time (6min), and large Stokes shift (124nm). The sensing mechanism of H2S was determined by HRMS analysis and DFT calculation. Moreover, Fla-DNP processes a wide range of multiple applications, including the detection of H2S in environmental water samples with good recovery rates ranging from 89.6% to 102.0%, as well as tracking the production of H2S during food spoilage. Meanwhile, the probe exhibits superior biocompatibility and can not only be available used for H2S detection in living cells but be further designed as an H2S-activated CO photoreleaser, based on which it can be developed as a targeted anti-cancer drug.

&lt;i&gt;Salmonella enterica&lt;/i&gt; species isolated from local foodstuff and patients suffering from foodborne illness: Surveillance, antimicrobial resistance and molecular detection

The aim of this study was to determine the prevalence of Salmonella enterica in raw chicken meat, eggs, and ready-to-eat foods containing poultry products and among patients suffering from diarrhea as a result of ingestion of this foodborne pathogen in Baghdad, Iraq. It assesses the antibiotics susceptibility, virulence and pathogenicity of S. enterica isolates. Thirteen Salmonella spp. isolates from foodstuff and seven from clinical patients were recovered from 80 and 20 samples, respectively. Isolates from foodstuff samples displayed the highest resistance to nalidixic acid (69.23%), followed by chloramphenicol (53.84%). Salmonella spp. isolated from clinical samples showed resistance to both azithromycin and cefotaxime at the same percentage level (71.42%). The results of antibiotic resistance gene amplification (gyrA, mphA) were analyzed and showed that these genes were present in 100% and 50% of phenotypically resistant isolates, respectively. Virulence genes invA, avrA, and sipB were found on average in 86% of food isolates, accounting for 69.2%, 92.3%, and 95%, respectively. In addition, the detection of these virulence genes among clinical isolates showed their presence at the same level (85.7%). Our study revealed that unhygienic chicken slaughterhouses and lack of food safety management are strong indicators of a high probability of the Salmonella presence in our food products in the Iraqi markets.

Two sides of the same coin: Kernel partial least-squares (KPLS) for linear and non-linear multivariate calibration. A tutorial

A tutorial is presented on the operation and properties of the non-linear multivariate regression model kernel partial least-squares (KPLS). After the discussion of a simple non-linear univariate problem, solved by regressing a dependent variable on the projection of an independent variable onto a set of Gaussian functions, the principles of KPLS are introduced for processing non-linear multivariate data. The following aspects are covered: (1) the estimation of the model sensitivity as a function of analyte concentration from error propagation concepts, (2) the proposal of a parameter measuring the degree of non-linearity, to avoid a black-and-white description of data sets as either linear or non-linear, (3) the use of the model parameters for variable selection. The application of KPLS to both simulated and experimental data sets is discussed, in the latter case involving near infrared spectra employed for the determination of quality parameters in foodstuff samples and fluorescence spectroscopic data for the study of systems of biological relevance. Computer codes written in the popular MATLAB and R environments are also provided.

A near-infrared fluorescent probe for imaging of bisulfite in living animals and its application in food samples

Bisulfite (HSO3−) has been widely used as an antioxidant, enzyme inhibitor and antimicrobial agent in foodstuffs, pharmaceutical and beverages industries. It is also a signaling molecular in the cardiovascular and cerebrovascular systems. Nevertheless, a high level of HSO3− can cause allergic reactions and asthmatic attacks. Accordingly, the monitoring of HSO3− levels possesses momentous significance from the perspectives of biological technology and food security supervision. Herein, a near-infrared fluorescent probe LJ is rationally constructed for sensing HSO3−. The fluorescence quenching recognition mechanism was realized by the addition reaction of electron-deficient CC bond in probe LJ and HSO3−. Probe LJ revealed multifarious preponderances such as longer wavelength emission (710 nm), low cytotoxicity, larger Stokes shift (215 nm), better selectivity, higher sensitivity (72 nM) and short response time (50 s). Encouragingly, probe LJ can detect HSO3− in living zebrafish and mice in vivo by fluorescence imaging techniques. In the meantime, probe LJ was also successfully employed to semi-quantitatively detect HSO3− in real foodstuff samples and water samples by the “naked-eye” colorimetry without the help of any special instruments. More importantly, quantitative detection of HSO3− in practical food samples was achieved through a smartphone application software. Consequently, probe LJ is expected to provide an effective and convenient way for the detection and monitoring of HSO3− in organisms and for food safety detection, which has tremendous application potential.

What about nitrogen? Using nitrogen as a carrier gas during the analysis of petroleum biomarkers by gas chromatography mass spectrometry

Gas chromatography mass spectrometry (GC–MS) is a commonly used method for organic geochemistry for both academic research and applications such as petroleum analysis. Gas chromatography requires a carrier gas, which needs to be both volatile and stable and in most organic geochemical applications helium or hydrogen have been used, with helium predominating for gas chromatography mass spectrometry. Helium, however, is becoming an increasingly scarce resource and is not sustainable. Hydrogen is the most commonly considered alternative carrier gas to helium but has characteristics that in certain respects make its use less practical, foremost is that hydrogen is flammable and explosive. But as hydrogen is increasingly used as a fuel, higher demand may also make its use less desirable. Here we show that nitrogen can be used for the GC–MS analysis of fossil lipid biomarkers. Using nitrogen, chromatographic separation of isomers and homologues can be achieved, but sensitivity is orders of magnitude less than for helium. It is reasonable to use nitrogen as a carrier gas in applications where low levels of detection are not needed, such as the characterization of samples of crude oil or foodstuffs, or potentially as part of a gas-mixture seeking to reduce helium-demand but maintain a level of chromatographic separation sufficient to support proxy-based characterizations of petroleum.