OOIR: Observatory of International Research

Papers

(The TQCC of Journal of Analytical Atomic Spectrometry is 7. The table below lists those papers that are above that threshold based on CrossRef citation counts [max. 250 papers]. The publications cover those that have been published in the past four years, i.e., from 2021-12-01 to 2025-12-01.)

Article	Citations
Detection of chromium in different valence states in water and soil using laser-induced breakdown spectroscopy combined with an ion enrichment chip	56
Nano-imaging mass spectrometry by means of high-energy laser desorption ionization (HELDI)	45
Back cover	36
Spectroscopic characterization of uranium atoms in uranium-dioxide laser-produced plasma in a high-vacuum environment	35
Back cover	34
Front cover	34
Correction: Development of a multi-isotopic (Pb, Fe, Cu) analytical protocol in gold matrices for ancient coin provenance studies	34
Back cover	31
Contents list	31
Build-a-bone: development of a matrix-matched reference material for quantitative analysis of bone with portable LIBS	30
Accurate thresholding using a compound-Poisson-lognormal lookup table and parameters recovered from standard single particle ICP-TOFMS data	30
Evaluation of miniaturized ultrasonic nebulization for high-efficiency sampling in characterization of silver nanoparticles by single particle inductively coupled plasma mass spectrometry	29
Further characterizing Eppawala-AP as a potential Cl-rich apatite Sr isotope reference material	29
Trigger-free LIBS using kHz and a few mJ laser in combination with random forest regression for the quantitative analysis of steel elements	29
Mass spectrometry insights into interactions of selenoprotein P with auranofin and cisplatin	29
Lithium-ion batteries: direct solid sampling for characterisation of black mass recyclates using graphite furnace atomic absorption spectrometry	29
Fast and high spatially resolved multielemental mapping of otoliths using IR&UV-femtosecond laser ablation-ICP-TOFMS	29
Two-stage semi-supervised machine learning for classification of Ti-rich nanoparticles and microparticles measured by spICP-TOFMS	27
An efficient Cd two-stage column system for high-precision determination of Cd isotopic compositions by double spike MC-ICP-MS	27
A simultaneous atomic absorption and emission spectrometer with dielectric barrier discharge for atomization and excitation	26
Detection of lead in water at ppt levels using resin-enrichment combined with LIBS-LIF	25
The potential of a multi-method platform centred on ICP-MS to provide new insights into the size-resolved quantification of TiO₂ particles in food	24
: a selection tool for asymmetric reflections of spherically bent crystal analyzers for high resolution X-ray spectroscopy	24
Precise determination of stable W isotopic compositions of seawater with Fe co-precipitation and double spike MC-ICP-MS	24
High-accuracy quantification of soil elements by laser-induced breakdown spectroscopy based on PCA-GS-ELM	23

Iron, copper and zinc isotope compositions of biological reference materials determined by MC-ICP-MS	22
Nanoparticle-enhanced laser-induced breakdown spectroscopy for serum element analysis using an Ag NP-coated filter paper substrate	22
Potential direct mass spectral elemental analysis of solids by microwave plasma torch surface release and ionization	21
High-precision double-spike Sn isotope analysis of geological materials by MC-ICP-MS	21
Instrumental mass-independent fractionation accounting for the sensitivity of the double spike proportion effect by MC-ICP-MS: a case study of Zn isotope measurements	21
Plasma emission intensity expansion of Zr metal and Zr oxide via microwave enhancement laser-induced breakdown spectroscopy	21
Investigation of signal enhancement in nanoparticle enhanced molecular LIBS of graphite	21
A newly synthesized reference material for in situ sulfur isotope measurement of sphalerite using laser ablation MC-ICP-MS	21
Improvement in the sensitivity of LA-ICP-MS bioimaging by addition of nitrogen to the argon carrier gas	21
The KNW rutile—a natural reference material for microbeam U–Pb age and trace element determination	20
Ultra-trace elemental determination of Si by means of graphite furnace-atomic absorption spectrometry	20
Development of a simple and rapid EDXRF method for quantification of ZrO₂ and HfO₂ in aqueous and organic process stream solutions generated from a zirconium extraction facility	20
Vesuvianite: a new mineral species of (U–Th)/He geochronology	20
Depth profiling of noble gases in ilmenite and olivine substrates	19
Investigation of Al Kα satellite lines through a high-efficiency multi-channel FSSR	19
Simultaneous analysis of gadolinium and surface imaging using a fiber-coupled acoustic wave-assisted microchip LIBS system	19
Inside front cover	19
Effect of matrix temperature on the LIBS signal of Au	19
Modified iterative wavelets for background removal in laser-induced breakdown spectroscopy based on fiber laser ablation	19
Assessing arsenic species in foods using regularized linear regression of the arsenic K-edge X-ray absorption near edge structure	19
Fast analysis of metal components in coal dust using spark emission spectroscopy	19
Measurement of ⁸⁷Sr/⁸⁶Sr in limestones after acid leaching and direct injection in a liquid chromatograph coupled to a multicollector ICP-MS	18
Development of sulfur isotope microanalysis of calcite using secondary ion mass spectrometry: methodology and matrix effects	18
Feasibility study to evaluate composition and degradation of orichalcum ingots through combined XRF and VIS-SWIR reflectance mapping	18
Front cover	18
Contents list	18
Comment on “Limitations in using the Cu isotopic composition of minerals from ancient copper mines for archaeometric purposes – a case study” by P. A. Penanes, M. Costas-Rodríguez, M. Moldovan, J. I.	18
Contents list	18
The feasibility of using a pyrite standard to calibrate the sulfur isotope ratio of marcasite during SIMS analysis	18
Bimodal data fusion of LIBS spectroscopy and plasma acoustic emission signals: improving the accuracy of machining process identification for low roughness samples	17
Experimental determination of ruthenium L-shell fluorescence yields and Coster–Kronig transition probabilities	17
In situ detection of neodymium isotopes using tunable diode laser absorption spectroscopy for nuclear forensic analysis	17
Hidra aeschynite-(Y): a potential natural reference material for microbeam Pb–Pb and Lu–Hf geochronology	17
High-sensitivity analysis of trace elements in water using femtosecond LIBS with dry droplet pretreatment on a metallic substrate	17
Method development for speciation analysis of silver nanoparticles and silver ions in green algae and surface waters at environmentally relevant concentrations using single particle ICP-MS	17
Spectral signal enhancement in laser-induced breakdown spectroscopy via arc discharge assistance	17
XRFast a new software package for processing of MA-XRF datasets using machine learning	17
High-precision quantification and low detection limits of chlorine and fluorine in coal via laser-induced breakdown spectroscopy	17
Simultaneously obtaining stable and radiogenic Nd isotope ratios through a single DGA column using double spike TIMS	17
Quantitative fluoride imaging of teeth using CaF emission by laser induced breakdown spectroscopy	16
Data augmentation using GANN in the quantitative LIBS analysis of scarce samples: a case study on polymetallic nodules from 5000 m ocean depth	16
Contents list	16
An emergency radiobioassay method for Pu, Am and Cm isotopes in urine samples using tandem quadrupole ICP-MS	16
TARIM calcite: a potential reference material for laser ICPMS in situ calcite U–Pb dating	16
Sampling and determination of antimony isotopes in airborne particles: an assessment of membrane filter materials	16
Inside back cover	16
On the use of end-on observation in optical emission spectroscopy measurements of the maximum electric field strength in the cathode sheath of Grimm-type glow discharges in helium	16
Synthesis and characterization of a U/Pu mixed-actinide microparticulate reference material	16
Zirconium analysis in microscopic spent nuclear fuel samples by resonance ionization mass spectrometry	16
Back cover	16

Cu fractionation, isotopic analysis, and data processing via machine learning: new approaches for the diagnosis and follow up of Wilson's disease via ICP-MS	15
Accurate determination of sulfur, selenium and tellurium in geological reference materials by isotope dilution inductively coupled plasma-tandem mass spectrometry (ID-ICP-MS/MS)	15
A new approach for baseline correction in laser induced breakdown spectroscopy	15
The Saha ionisation equilibrium shift correction model applied to MPT-OES for analysing complex matrix samples: an example for brine samples	15
Investigation of a method for the correction of self-absorption by Planck function in laser induced breakdown spectroscopy	15
Morphology–spectral correlations of laser-induced Al plasma with plate wall spatial confinement	15
Sensitive determination of neodymium isotope in seawater by multi-collector inductively coupled plasma mass spectrometry with ultrasound nebulization-dielectric barrier discharge vapor generation as s	15
A digestion-purging-trapping method for precise stable mercury isotope measurements of natural carbonates	15
Utilization of ionic liquids for preferential separation of thorium during the determination of trace metallic constituents in thorium matrix using ICP-OES	15
Boron elemental and isotopic determination via the BF diatomic molecule using high-resolution continuum source graphite furnace molecular absorption spectrometry	15
A synthesized sphalerite standard for in situ analysis of sulfur isotopes and trace elements by LA-MC-ICP-MS and LA-ICP-MS	15
Front cover	14
XPS characterization of vanadium carbide species formed during the atomization process in electrothermal atomic absorption spectroscopy	14
Speciation of copper in human serum using conjoint liquid chromatography on short-bed monolithic disks with UV and post column ID-ICP-MS detection	14
Back cover	14
A convective heated digestion system with closed vessels: a new digestor for elemental inorganic analysis	14
Determination of Ce and La in REE-rich ores using handheld LIBS and PLS regression	14
Strategies to enhance figures of merit in ICP-ToF-MS	14
Isoclock: a free and novel routine for common Pb correction in U–Th–Pb data reduction of LA-ICP-MS analysis	14
Effect of repeated irradiation on laser-induced breakdown spectroscopy of copper immersed in a sodium chloride aqueous solution and normalization with bubble collapse time	14
Front cover	14
Comparison of monosegmented flow analysis to flow injection for single particle inductively coupled plasma mass spectrometry	14
Analytical comparisons of handheld LIBS and XRF devices for rapid quantification of gallium in a plutonium surrogate matrix	14
An image auxiliary method for laser-induced breakdown spectroscopy analysis of coal particle flow	14
Impact of Ag NPs on temporal evolution of plasma emission in nanoparticle-enhanced laser-induced breakdown spectroscopy	14
Uranium isotopic analysis in unpurified solutions by ICP-MS	14
Concomitant ion matrix effects in SCGD-OES enhanced with formic acid	14
Contents list	14
Insights into the role of transition and noble metals mediating photochemical vapor generation	14
Use of single particle inductively coupled plasma mass spectrometry for the study of zinc oxide nanoparticles released from fabric face masks	13
Elemental composition analysis of electronic waste using neutron-based analytical techniques: a novel approach to assessing environmental and resource recovery potential	13
A novel (NH₄)₂HPO₄–LiBO₂ fusion technique for bulk silicate rock analysis by laser ablation-inductively coupled plasma-mass spectrometry	13
A portable smartphone platform with FeNPs@g-C₃N₄ nano-enzyme for visual and on-site sensing of F⁻ and Al³⁺ in tea	13
Improved uranium isotopic ratio determinations for the liquid sampling-atmospheric pressure glow discharge orbitrap mass spectrometer by use of moving average processing	13
Exploratory studies on total reflection X-ray fluorescence spectrometry combined with slurry sampling for the multi-element analysis of copper-nickel sulfide ore	13
Front cover	13
In situ measurements using hand-held XRF spectrometers: a tutorial review	13
Contents list	13
“Non-invasive” portable laser ablation sampling for lead isotope analysis of archaeological silver: a comparison with bulk and in situ laser ablation techniques	13
A precise and accurate analytical method for determination of osmium isotope ratios at the 1–15 pg level by using a MC-ICP-MS equipped with sparging introduction and high-sensitivity discrete dynode-t	13
Difficulties and artefacts in cryo-fixation of ovarian tissues for X-ray fluorescence analyses	13
Correction: Quantification of ferric iron content in minerals via the STEM-EELS-mapping method	13
Improvements in low-level radionuclide measurement capability through use of the Apex Q sample introduction system combined with ICP-MS/MS	13
A Pb-free Sn–Bi alloy mount preparation method for secondary ion mass spectrometry (SIMS) analyses	13
Synthesis of a new olivine reference material by a novel method for in situ iron and magnesium isotope analyses using laser ablation MC-ICP-MS	13
Apatite MAP-3: a new homogeneous and low common lead natural reference for laser in situ U–Pb dating and Nd isotope analysis	13
Accuracy enhancement of laser-induced breakdown spectroscopy using a combination of a confinement ring and quadrupole discharge arc	13
High-precision analysis of calcium isotopes using a Nu Sapphire collision cell (CC)-MC-ICP-MS	13
Multiple-element analysis of coal using collinear double-pulse laser-induced breakdown spectroscopy	13
Studying the degradation of bulk PTFE into microparticlesviaSP ICP-MS: a systematically developed method for the detection of F-containing particles	13
A novel LIBS method for quantitative and high-throughput analysis of macro- and micronutrients in plants	13
New natural garnet reference materials for determining the oxidation state of iron in garnet using the electron microprobe flank method	13
A novel approach for the determination of exchangeable copper in serum using protein precipitation	13
Enhancing soil geographic recognition through LIBS technology: integrating the joint skewness algorithm with back-propagation neural networks	13
TrCSL: a transferred CNN-SE-LSTM model for high-accuracy quantitative analysis of laser-induced breakdown spectroscopy with small samples	13
A two-step chromatographic purification method for Ni for its isotopic analysis by MC-ICP-MS	13
Innovative sample preparation method using a conductively heated digestion system for trace element analysis of radioactive oil sludge by ICP-OES	13
Effects of laser-focusing geometry on underwater laser ablation and LIBS measurement of a submerged target	13
Interference-free electron probe micro-analysis of bromine in halogen-bearing minerals and glasses: high-resolution measurements and quantitative elemental mapping	13
Magneto-electrical fusion enhancement of LIBS signals: a case of Al and Fe emission lines' characteristic analysis in soil	13
Long-term reproducibility detection method for quantitative LIBS using Kalman filtering	12
Quantitative analysis of Cu, Zn, and Pb elements in ores by X-ray fluorescence using a hierarchical convolutional network with attention excitation	12
Inside front cover	12
Front cover	12
High throughput laser ablation ICP-MS bioimaging of silver distribution in animal organisms and plant tissue after exposure to silver sulfide nanoparticles	12
ICP-OES determination of major and trace composition of gadolinium(iii) oxide crystals doped with europium	12
Challenges in measuring nanoparticles and microparticles by single particle ICP-QMS and ICP-TOFMS: size-dependent transport efficiency and limited linear dynamic range	12
A community-led calibration of the Zr isotope reference materials: NIST candidate RM 8299 and SRM 3169	12
Particle generated spectral interferences in single particle ICP-MS: a roadblock to accurate nanometrology	12
A comparison of calibration strategies for quantitative laser ablation ICP-mass spectrometry (LA-ICP-MS) analysis of fused catalyst samples	12
A new potential synthetic pyrrhotite reference material for Fe–S isotope microanalysis	12
A novel chemical purification method for accurate Sn isotope measurement by MC-ICP-MS	12
A review of spectral broadening in laser atomic absorption spectroscopy	12
A lab-based micro-X-ray fluorescence spectrometer with high photon flux and spatial resolution for ancient ceramic research	12
Atomic Spectrometry Update: review of advances in elemental speciation	12
Doppler-free ablation fluorescence spectroscopy of Ca for high-resolution remote isotopic analysis	12
Asymmetric Rowland circle geometries for spherically bent crystal analyzers in laboratory and synchrotron applications	12
On a single method for determining As and Hg in dietary supplements by CVG-MIP OES: optimization of the multimode sample introduction system	12
Effects of argon on the analytical properties of a microwave-sustained, inductively coupled, atmospheric-pressure plasma	12
In situ quantitative analysis of beryllium by EPMA: analytical conditions and further insights into beryllium geochemistry	12

Contents list	12
Quantitative determination of iron citrate/malate complexes by isotope–dilution hydrophilic interaction liquid chromatography – electrospray MS/inductively coupled plasma MS	12
Dolomite reference material synthesized by pressureless sintering for laser ablation MC-ICP-MS carbon and magnesium isotope analysis	12
Cloud point extraction hyphenated to single-particle ICP-MS minimizes background signals and improves particle size detection limit for ultra trace analysis of nanoparticulate rhodium	12
Inside front cover	12
A transferred multitask regularization convolutional neural network (TrMR-CNN) for laser-induced breakdown spectroscopy quantitative analysis	12
LA-ICP-MS/MS-based Rb–Sr isotope mapping for geochronology	12
Brama: a new freeware Python software for reduction and imaging of LA-ICP-MS data from U–Pb scans	12
Fundamental studies of laser ablation ICPMS using a nitrogen plasma source and helium, argon and nitrogen as carrier gas	12
Fast detection of hazardous chlorinated volatile organic compounds via laser-induced breakdown spectroscopy	11
Evaluating accuracy improvements of laser ablation ICPMS element analysis in silicate glasses and carbonates via downhole fractionation correction – an old problem re-assessed	11
Contents list	11
Inside back cover	11
Inside back cover	11
Assessment of matrix effects in boron isotope analysis using 257 nm fs-LA and 193 nm ns-LA-MC-ICP-MS with new tourmaline reference materials	11
LIBS analysis of elemental carbon and fixed carbon in coal by dual-cycle regression based on matrix-matched calibration	11
Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages	11
A new reference material for O–Sr isotope determination in epidote using a micro-beam	11
Atomic spectrometry update: review of advances in X-ray fluorescence spectrometry	11
Uranium enrichment measurements using tunable laser spectroscopy coupled with fiber-optic laser-induced breakdown spectroscopy	11
Automated detection of element-specific features in LIBS spectra	11
Comparison of different mass bias correction procedures for the measurement of mercury species-specific isotopic composition by gas chromatography coupled to multicollector ICP-MS	11
Layer-resolving ability and model analysis of LIBS for multilayer samples with a four-layer structure under different focusing conditions	11
Improved alkaline fusion method for B isotope and concentration measurements of silicate materials	11
Calcite TLM and LSJ07 – two natural low-Sr reference materials for microbeam Sr isotope analysis	11
Development of two novel natural calcite reference materials for enhanced in situ elemental and Sr isotopic analysis	11
PXCG-1 and PXCG-2: two reference materials for gypsum U–Th dating	11
A miniaturized microplasma excitation source coupled with photochemically induced volatile species generation as a cost-effective tool for in situ mercury pollution analyses	11
Contents list	11
Determination of polysulfide anions and molecular sulfur via coupling HPLC with ICP-MS	11
Investigating the sensitivity difference of gaseous and particulate carbon in two-phase sample transport in LA-ICP-MS	11
Accurate determination of trace silver in geological reference materials by inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS)	11
Compound specific stable carbon isotope analysis of aromatic organic contaminants in water using gas chromatography coupled to mid-infrared laser spectroscopy	11
Operando laboratory XAS on battery materials using the DANOISE cell in a von Hámos spectrometer	10
Quantitative elemental mapping of chondritic meteorites using laser ablation-inductively coupled plasma-time of flight-mass spectrometry (LA-ICP-TOF-MS)	10
Separation and isotope ratio measurements of actinides and lanthanides in spent nuclear fuel samples by CE-MC-ICP-MS	10
Data processing made easy: standalone tool for automated calculation of isotope ratio from transient signals – IsoCor	10
Quantitative imaging of fluorine in human teeth by cryogenic laser ionization time-of-flight mass spectrometry	10
Filament induced breakdown spectroscopy with enhanced excitations from plasma gratings	10
Enhanced elemental and mineralogical imaging of Cu-mineralized rocks by coupling μ-LIBS and HSI	10
High-precision MC-ICP-MS measurements of Cd isotopes using a novel double spike method without Sn isobaric interference	10
Highly resolved detection of deuterium at atmospheric pressure	10
AC needle-to-needle bare electrode discharge with nebulized sample injection for elemental analysis	10
Determination of thallium isotopic composition through MC-ICP-MS with mass bias corrected using admixed W	10
Effect of laser polarization on molecular emission from femtosecond LIBS	10
On-line vacuum degree monitoring of vacuum circuit breakers based on laser-induced breakdown spectroscopy combined with random forest algorithm	10
Application of laser-induced breakdown spectroscopy with a generalized regression neural network and LASSO-type methods for estimation of arsenic and chromium in soil	10
Novel calibration approach for particle size analysis of microplastics by laser ablation single particle-ICP-MS	10
Automated analysis of natural variations in isotopes of silicon by the thermal decomposition of BaSiF ₆	10
An efficient and stable sample preparation and calibration strategy for nanoparticle analysis using laser ablation single particle-ICP-MS	10
Ultra-sensitive determination of mercury in flue gas by atmospheric pressure glow discharge atomic emission spectrometry coupled with gold amalgam enrichment	10
Mechanism of elemental fractionation during femtosecond laser ablation revealed by high-time-resolution MC-ICP-MS analysis of ²⁰⁸Pb/²³²Th ratios in single particles	10
Kinetic analysis of boron therapeutics in head and neck cancer cells by complementary bulk ICP-MS and single-cell (scICP-MS) approaches	10
Front cover	10
Study on the evaluation of the aging grade for industrial heat-resistant steel by laser-induced breakdown spectroscopy	10
Integration of capillary vibrating sharp-edge spray ionization as a nebulization device for ICP-MS	10
Classification of uneven steel samples by laser induced breakdown spectroscopy based on a Bessel beam	10
Combination of the internal standard and dominant factor PLS for improving long-term stability of LIBS measurements	10
A comprehensive chromatographic method for sequential separation of Pb, Rb, Sr, Nd, Sm, Lu, U, and Hf for high-precision isotope analysis of micro-sized silicate samples	10
A deep spectral prediction network to quantitatively determine heavy metal elements in soil by X-ray fluorescence	9
In situ Hf isotope analysis of cassiterite by LA-MC-ICP-MS: protocol and applications	9
Multi-channel dilution analysis	9
Flow techniques in the analysis of biological samples by inductively coupled plasma mass spectrometry – a review	9
Pb isotope ratio and trace element analysis using VUV-TOF mass spectrometry: applications to NIST 610/612 and zircon FC1	9
Calibration and application of a large-scale LIBS project based on transfer learning in the online quantitative analysis of coal	9
Contents list	9
Community Leaders: Ramon M. Barnes	9
Rapid isotopic analysis of uranium particles by laser ablation MC-ICP-MS	9
Towards the best total consumption infrared-heated sample introduction system for nanoparticle measurement using single particle inductively coupled plasma mass spectrometry	9
Chemical vapour generation assisted by Cr³⁺/KCN coupled to atomic fluorescence spectrometry for ultrasensitive determination of cadmium in water and rice samples	9
Machine learning-assisted laser-induced breakdown spectroscopy for estimating substrate surface temperatures	9
Catching up on calibration-free LIBS	9
High-precision lithium isotopic analysis using the Nu Sapphire MC-ICP-MS	9
Partial matrix matching multi-energy calibration for direct quantification of Al, Fe, Li and Si in spodumene by laser-induced breakdown spectroscopy	9
Synthesis of molybdenite reference materials for in situ molybdenum and sulfur isotope measurement using laser ablation MC-ICP-MS	9
Size determination of nanoparticles by ICP-ToF-MS using isotope dilution in microdroplets	9
Contents list	9
Enhancement of LIBS plasma and efficient collection of emitted light by open smooth triangular cavities	9
First demonstration of in situ Lu–Hf dating using LA-ICP-MS/MS applied to monazite	9
Influence of ambient pressure on spatial–temporal evolution of local thermodynamic equilibrium for laser-induced plasma	9
Back cover	9
High spatial resolution and precision NanoSIMS for sulfur isotope analysis	9
Robust determination of low Ti contents in zircon using LA–ICP–MS/MS with NH₃ reaction gas	9
Classification of gaseous UF₆ assay by femtosecond LIBS in the 424.4 nm spectral region using numerical HOGSVD-DTW features	9
Artificial neural network for high-throughput spectral data processing in LIBS imaging: application to archaeological mortar	9
Front cover	9
A Gaussian spot overlap ablation model for prediction of aluminium alloy spectral peak intensity in high pulse repetition frequency LIBS	9
Improving quantitative analysis of cement elements in laser-induced breakdown spectroscopy through combining matrix matching with regression	9
Front cover	9
Contents list	8
Decoding the interfering L-lines by artificial neural network-based modeling for direct analysis of lanthanides in water samples using total reflection X-ray fluorescence spectrometry	8
A molecular laser-induced breakdown spectroscopy technique for the detection of nitrogen in water	8
Determination of the ¹⁴⁴Ce/²³⁸U atomic ratio in spent nuclear fuel using double spike isotope dilution mass spectrometry	8
K, Mg, and Ca isotopic analysis from a single aliquot of thirteen biological certified reference materials	8
A solid substrate based on clay minerals for sampling organic liquids in molecular LIBS analysis	8