López García, Ignacio Francisco

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López García, Ignacio Francisco

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López García, Ignacio Francisco

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Universidad de Murcia. Departamento de Química Analítica

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Open Access
Toward nitrite-free curing: evaluation of a new approach to distinguish real uncured meat from cured meat made with nitrite
(MDPI, 2021-02-03) Hernández, Juan de Dios; Castell Martínez, Ana; Arroyo Manzanares, Natalia; Guillén, Isidro; Vizcaíno, Pascuali; López García, Ignacio Francisco; Hernández Córdoba, Manuel; Viñas López-Pelegrin, Pilar; Química Analítica
After the International Agency for Research on Cancer (IARC) classified ingested nitrites and nitrates as “probably carcinogenic to humans” under conditions favoring endogenous nitrosation, several meat products labeled as “made without nitrite” were launched. In order to distinguish uncured products truly made without nitrite from cured products made with any nitrite source (vegetal or mineral), this article presents an approach to detect and quantify nitrite from different origins added to meat. The method consists on the determination of nitrous oxide as a target compound using headspace gas chromatography–mass spectrometry (HS-GC–MS). Nitrous oxide (N2O) is formed after two reduction steps: from nitrite to nitric oxide (NO) and then to N2O. The NO is bound to myoglobin (Mb) or metmyoglobin (Met-Mb), forming a complex, which is subsequently released using sulfuric acid, which also favors the reduction to N2O. The HS-GC–MS conditions were split ratio 1:10; injection temperature at 70 ºC; incubation temperature at 30 ºC and time 45 min; and injection volume 1 mL. As a result, a relationship was established between the concentration of nitrite in cooked ham samples and the area of the N2O peak generated, meaning that this method allows the quantification of added nitrite within a concentration range of 10 to 100 mg/kg.
Open Access
Ion mobility spectrometry as an emerging tool for characterization of the volatile profile and identification of microbial growth in pomegranate juice
(Elsevier, 2021-12-17) Castell Martínez, Ana; Arroyo Manzanares, Natalia; Hernández, Juan de Dios; Guillén, Isidro; Vizcaíno, Pascuali; López García, Ignacio Francisco; Hernández Córdoba, Manuel; Viñas López-Pelegrin, Pilar; Química Analítica
Headspace - gas chromatography (HS-GC) coupled to ion mobility spectrometry (IMS) is proposed as an alternative to plate counting to detect and quantify the microbial contamination in pomegranate juice. Thus, contaminated samples by the yeast Saccharomyces cerevisiae were monitored during 6 non-consecutive days over two weeks using two types of preservatives (a sorbate/benzoate mixture and a natural preservative from vegetable extracts). IMS is an emerging technique with high potential for volatile organic compounds (VOCs) monitoring because its high sensitivity and separation power of ions. The fingerprint of the samples allowed to establish difference in the volatile composition of contaminated and non-contaminated samples. Ethyl acetate, ethyl butyrate and limonene were characterized obtaining limits of detection and quantification below 0.029 and 0.097 μg/g, respectively. Furthermore, chemometric models were performed to detect contaminated pomegranate juice and to assess the concentration of yeast, obtaining a validation success of 100 and 90.91%, respectively.
Open Access
Ultrasound assisted extraction approach to test the effect of elastic rubber nettings on the N-nitrosamines content of ham meat samples
(MDPI, 2021-10-24) Giménez Campillo, Claudia; Pastor Belda, Marta; Campillo Seva, Natalia; Hernández, Juan de Dios; Guillén, Isidro; Vizcaíno, Pascuala; López García, Ignacio Francisco; Hernández Córdoba, Manuel; Arroyo Manzanares, Natalia; Viñas López-Pelegrin, Pilar; Química Analítica
Nitrosamines (NAs), which are catalogued as carcinogenic compounds, may be present in meat products due to the conversion of nitrites and as result of migration from elastic rubber nettings used. A method based on ultrasonic assisted extraction coupled with dispersive liquid–liquid microextraction as sample treatment and gas chromatography-mass spectrometry as separation and detection technique was proposed for the determination of twelve NAs in cooked ham samples. The method was validated by evaluating linearity (0.5–1000 ng g−1), matrix effect, sensitivity (detection limits were between 0.15 and 1.4 ng g−1) and precision, which was below 12%. Five NAs were found in the samples with levels ranging from not quantifiable to 40 ng g−1. The effect of the elastic rubber nettings on the nitrosamine content of meat was evaluated by comparing the levels found in products made with several plastics or thread in the presence of additives.
Open Access
Advanced materials for magnetic solid-phase extraction of mycotoxins: a review
(Elsevier, 2024-06-20) Castell Martínez, Ana; Arroyo Manzanares, Natalia; Viñas López-Pelegrin, Pilar; López García, Ignacio Francisco; Campillo Seva, Natalia; Química Analítica
Mycotoxins can occur at various stages of the food production process. Due to the toxicity of many of these compounds for human health, the development of analytical methodologies that allow their detection and remediation in food is of great interest. However, food analysis is challenging due to the complexity of the matrices, so sample treatment is a crucial step. Magnetic solid-phase extraction (MSPE) has become one of the most popular green approaches for the isolation of mycotoxins from complex matrices. Furthermore, advanced magnetic materials as molecularly imprinted polymers, metal-organic frameworks and covalent organic frameworks have emerged as promising candidates for MSPE, as they offer a simple and efficient application for mycotoxin extraction due to the possibility to modify and functionalize their surface according to specific requirements. This review provides an overview of the synthesis and recent applications of these sorbents for the MSPE isolation of mycotoxins from complex matrices.
Open Access
Ion mobility spectrometry and mass spectrometry coupled to gas chromatography for analysis of microbial contaminated cosmetic creams
(Elsevier, 2020-07-11) García Nicolás, María; Arroyo Manzanares, Natalia; Hernández, Juan de Dios; Guillén, Isidro; Vizcaino, Pascuala; Sánchez Rubio, Marta; López García, Ignacio Francisco; Hernández Córdoba, Manuel; Viñas López-Pelegrin, Pilar; Química Analítica
The most commonly used technique for monitoring microbial contamination in cosmetic products is plate counting. In this contribution, headspace - gas chromatography (HS-GC) coupled to mass spectrometry (MS) or ion mobility spectrometry (IMS) is proposed as a technique to evaluate rapidly and accurately the state of microbial colonies in cosmetic creams using the volatile organic compounds produced by microorganisms (MVOC). The work focuses on monitoring two of the microorganisms that most frequently occur in such creams, Candida albicans and Staphylococcus aureus. In addition, two different types of ingredient with antimicrobial properties (a chemical preservative and a natural preservative) were added to study the behaviour of these microorganisms under different conditions. The facial creams were elaborated and inoculated with the two above microorganisms, and then sampled weekly for 4 weeks, analysing the evolution of the MVOCs by HS-GC-MS and HS-GC-IMS. In addition, microbial contamination was determined by the classical plate counting method. The pH, colour, viscosity and water activity parameters were also measured. The use of chemometric tools is essential because of the large amount of data generated, and different models based on discriminant analysis with an orthogonal projection on latent structures (OPLS-DA) were constructed. The optimal models obtained by both analytical techniques allowed differentiation between contaminated and non-contaminated creams, with a validation success rate of 94.4%. In addition, MVOC monitoring also allowed assessment of the microbial concentration.