The sample matrix is a major factor affecting the accuracy of LIBS quantitative results. The “matrix effects” are due to changes of emission line intensities of some elements when the physical properties and/or the chemical composition of the sample matrix varies. These effects primarily influence the production of atomized material by ablation and the excitation properties of the laser plasma. There are two kinds of

matrix effects: physical and chemical. The so-called “physical” matrix

effects are related to the physical properties (e.g., grain size, texture, reflectivity and hardness) of the sample surface on ablation parameters.

These effects may result in an alteration of the amount of ablated

mass which may cause a variation of the line emission intensity even

if the concentration is the same in the various matrices. The “chemical” matrix effects occur when the emission behavior of one element is altered by the presence of another one. For example, an element present in equal concentration in two different host materials may exhibit different LIBS emission intensities. These effects make it very challenging to find matrix-matched standards to be used to perform quantitative LIBS analysis of natural samples. ciao Giorgio

Matrix effect occurs in any analytical technique, it is any signal coming from the environment where its element / compound of interest is located. In this case, the emission of light at a wavelength coinciding with that of interest, or even some absorption effect generated by a substance, impairing its measurement. I hope it helped you.

Thankyou Moacir Brito for your helpful answer.Please explain more in detail.

In LIBS I think that different components evaporate at different velocity when heated by the laser pulse, with the consequence that the atomic ratio in the plasma is different from that of the surface.

Another effect can be related to the topography of the surface, that can be reflected on the plasma shape.

The sample matrix is a major factor affecting the accuracy of LIBS quantitative results. The “matrix effects” are due to changes of emission line intensities of some elements when the physical properties and/or the chemical composition of the sample matrix varies. These effects primarily influence the production of atomized material by ablation and the excitation properties of the laser plasma. There are two kinds of

matrix effects: physical and chemical. The so-called “physical” matrix

effects are related to the physical properties (e.g., grain size, texture, reflectivity and hardness) of the sample surface on ablation parameters.

These effects may result in an alteration of the amount of ablated

mass which may cause a variation of the line emission intensity even

if the concentration is the same in the various matrices. The “chemical” matrix effects occur when the emission behavior of one element is altered by the presence of another one. For example, an element present in equal concentration in two different host materials may exhibit different LIBS emission intensities. These effects make it very challenging to find matrix-matched standards to be used to perform quantitative LIBS analysis of natural samples. ciao Giorgio

The intensity of an element in the laser induced plasma will be affected by the other elements present in the matrix. The amount of its effect will be dependent on the physical and chemical properties of the element in the matrix as well as its coordination with the required elements. So matrix effect is important factor which decides the signal of a required elements in the sample. This effect play an important role in plotting a calibration curve. One should be careful and take into account the matrix effect during plot of calibration curve.

I agree with the previous answers.

In addition, Matrix effect in LIBS is a very important parameter. This can affect the signal of a specific wavelength (increase the error bar of repeated measurements). This may add to the week point of LIBS (high RSD values compared with many other spectroscopic techniques). This effect can be affecting the intensity of the spectral line either as a positive or a negative bias. In both cases it will give an undesired change in the signal. The main sources of Matrix effect are Physical and chemical compositions. It can be compensated for, by the use of similar matrix standards (in case of using standards) or by increasing the no. of replicated in standard-less procedures.

Matrix effect is a kind of variation of analyte response by different elements within the original bulk material matrix

is referred to as fractionation or matrix effects, and has been widely observed and studied in another spectroscopic techniques such as inductively-coupled plasma atomic emission spectroscopy (ICP-AES), and laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS). Fractionation or matrix effects render analytical techniques less effective for quantitative analysis.

Physical matrix effects occur due to variability in the composition, grain size, texture, reflectivity, and hardness of the surface of a geomaterial. For example, the magnitude of laser energy coupling with the surface and resultant intensity of the LIBS signal generated is influenced by the roughness of the surface [76, 77].

The influence of matrix inhomogeneities can be ameliorated by homogenization of the sample (though this nullifies one of the main advantages of LIBS), utilization of an algorithm to reject anomalous spectra that are non-representative of the bulk sample, or, more commonly, interrogation of the sample with hundreds or even

thousands of laser pulses distributed in a grid pattern [78].

Therefore can be say that Matrix effects is a kind of ample inhomogeneities and differences in physical properties,

such as reflectivity and hardness of the surface, lead to variations in the line intensities when multiple spectra are collected from the same sample and as I said before it has to do with the coupling between the laser pulse and the surface of the material. Because LIBS is a surface analysis technique, deposits such as oxidation layers or fingerprint residue can interfere with the determination of the underlying bulk composition. To address these issues several laser pulses are often used to clean the sample surface before collecting tens or

hundreds of spectra distributed in a grid pattern. The problems associated

with poor precision can be diminished by data normalization [65]or by ensemble averaging [66].

Ref. Laser Induced Breakdown Spectroscopy: Theory & Applications, V. 182, Sergio Musazzi, 2014.

So matrix effect can contribute to the RSD in measurements if not considered in the analytical system. It can be considered as a serious source of error in measurements if not compensated for. I think it is a main source of variation in the LIBS signal.