Bench-top Spectrometer Research Articles

Ultra-portable, wireless smartphone spectrometer for rapid, non-destructive testing of fruit ripeness.

We demonstrate a smartphone based spectrometer design that is standalone and supported on a wireless platform. The device is inherently low-cost and the power consumption is minimal making it portable to carry out a range of studies in the field. All essential components of the device like the light source, spectrometer, filters, microcontroller and wireless circuits have been assembled in a housing of dimensions 88 mm × 37 mm × 22 mm and the entire device weighs 48 g. The resolution of the spectrometer is 15 nm, delivering accurate and repeatable measurements. The device has a dedicated app interface on the smartphone to communicate, receive, plot and analyze spectral data. The performance of the smartphone spectrometer is comparable to existing bench-top spectrometers in terms of stability and wavelength resolution. Validations of the device were carried out by demonstrating non-destructive ripeness testing in fruit samples. Ultra-Violet (UV) fluorescence from Chlorophyll present in the skin was measured across various apple varieties during the ripening process and correlated with destructive firmness tests. A satisfactory agreement was observed between ripeness and fluorescence signals. This demonstration is a step towards possible consumer, bio-sensing and diagnostic applications that can be carried out in a rapid manner.

Gradient-based solvent suppression methods on a benchtop spectrometer.

Benchtop NMR emerges as an appealing alternative to widely extend the scope of NMR spectroscopy in harsh environments and for on-line monitoring. Obviously, the use of low-field magnets induces a dramatic reduction of the spectral resolution leading to frequent peak overlaps. This issue is even more serious because applications such as chemical process monitoring involve the use of non-deuterated solvents, leading to intense and broad peaks overlapping with the signals of interest. In this article, we highlight the need for efficient suppression methods compatible with flowing samples, which is not the case of the common pre-saturation approaches. Thanks to a gradient coil included in our benchtop spectrometer, we were able to implement modern and efficient solvent suppression blocks such as WET or excitation sculpting to deliver quantitative spectra in the conditions of the on-line monitoring. While these methods are commonly used at high field, this is the first time that they are investigated on a benchtop setting. Their analytical performance is evaluated and compared under static and on-flow conditions. The results demonstrate the superiority of gradient-based methods, thus highlighting the relevance of implementing this device on benchtop spectrometers. The comparison of major solvent suppression methods reveals an optimum performance for the WET-180-NOESY experiment, both under static and on-flow conditions. Copyright © 2016 John Wiley & Sons, Ltd.

Non‐Destructive or Noninvasive? The Potential Effect of X‐Ray Fluorescence Spectrometers on Luminescence Age Estimates of Archaeological Samples

The non‐destructive nature of X‐ray fluorescence (XRF) spectrometers is a principal reason for an increase in their use in archaeological science over the last 15 years, especially for analyzing museum‐curated artifacts and in situ site fabrics. Here, we show that low‐power XRF spectrometry can be detrimental for luminescence dating (surface applications such as mud‐wasp nest dating in particular). We investigated the effects of irradiation by X‐rays emitted from handheld and benchtop spectrometers on optically stimulated luminescence (OSL) signals. Measurements were taken using a portable OSL (pOSL) unit on the following unprepared archaeological materials: sedimentary quartz grains, pottery, a mud‐wasp nest, stone tools, and a rock flake with anthropogenically applied pigment and natural pigmentation (iron oxides). We observed an increase in luminescence compared to initial background counts for all materials tested, which could lead to overestimation of age determinations in some situations. Our experiment provides a reminder of the potential effects of X‐ray radiation, and the need for thorough documentation of all recording and analytical techniques applied to archaeological materials.

Evaluation of benchtop versus portable near-infrared spectroscopic method combined with multivariate approaches for the fast and simultaneous quantitative analysis of main sugars in syrup formulations

In this work a total of 116 syrup samples was investigated in order to establish predictive models for glucose, fructose and sucrose of sufficient accuracy based on partial least squares regression. The samples are divided into two main groups a) standard syrups b) reformulated syrups. The latter products can be distinguished via the very low amount of glucose and sucrose and a high amount of fructose which makes them suitable for special nutrition. Near-infrared spectroscopy was applied together with Multivariate Analysis to develop a new method for quality control of syrups. Comparison between a portable spectrometer and the benchtop device showed that the reduced wavelength range and reduced resolution of the portable device is sufficient to receive calibrations with R2 ≥ 0.96 for standard syrups with comparable SEP values of 1.30 g/100 g vs. 1.19 g/100 g, 0.94 g/100 g vs. 0.99 g/100 g and 2.04 g/100 g vs. 2.46 g/100 g for glucose, fructose and sucrose respectively using the handheld device. The SEP values led to high RPD values of 5.56 vs. 5.26, 4.30 vs. 4.72, 5.06 vs. 4.20 for fructose, glucose and sucrose respectively. The R2 values for reformulated syrups were 0.94 with a SEP of 1.04 g/100 g and a RPD value of 2.58 for the portable spectrometer and 0.92 with a SEP of 0.92 g/100 g and a resulting RPD value of 2.84 for the benchtop spectrometer. The method is suitable to be implemented for quality control in the producing industry as well as in grocery stores.

Design Study of an Atmospheric Pressure Photoionization Interface for GC-MS.

This contribution reports on the development of an atmospheric pressure photoionization (APPI) source interfacing a gas chromatograph (GC) with a bench-top Orbitrap high resolution mass spectrometer (MS). We present efforts on method development aiming at high temperature stability (325°C), constant low impurity levels upon prolonged source operation, and efficient reaction volume irradiation combined with minimum peak broadening. The performance throughout each iterative development step was carefully assessed. The final GC-APPI-MS setup demonstrated femtogram-on-column sensitivity and chromatographic peaks of Gaussian shape with base peak widths <2 s for even the highest boiling compounds present in different EPA standard mixtures. Graphical Abstract ᅟ.

Field-Scale Predictions of Soil Contaminant Sorption Using Visible–Near Infrared Spectroscopy

Models used to evaluate leaching of contaminants to groundwater are very sensitive to sorption coefficients ( Kd). These models need reliable Kd data at the field scale, but the number of samples required makes the classic batch sorption experiments inappropriate for this purpose. Since visible–near infrared (vis–NIR) spectroscopy is an inexpensive and fast method, it has been used for predicting soil properties related to soil sorption capacity. In this study, we aimed to predict the spatial variation of Kd from vis–NIR spectra for two contaminants: phenanthrene (sorbed on organic fractions) and glyphosate (sorbed on mineral fractions). Forty-five bulk soil samples were collected from an agricultural field in Estrup, Denmark, in a 15 m × 15 m grid. Samples were air-dried, sieved to 2 mm and analysed for selected soil properties. Sorption coefficients were obtained from a batch equilibration experiment. Soil samples were measured with a bench-top spectrometer covering the vis–NIR range between 400 nm and 2500 nm. Partial least squares regression with full cross-validation was used to correlate the soil spectra with Kd values and soil properties. The sorption coefficients ranged from 345 L kg−1 to 886 L kg−1 and from 162 L kg−1 to 536 L kg−1 for phenanthrene and glyphosate, respectively. The regression coefficients showed that phenanthrene sorption was correlated with total organic carbon, aluminium oxides and cation exchange capacity, and glyphosate sorption with clay minerals and iron oxides. By means of the vis–NIR spectra we were able to predict phenanthrene ( R2 = 0.95, RMSECV = 31 L kg−1) and glyphosate ( R2 = 0.79, RMSECV = 45 L kg−1) sorption capacities. A model using vis–NIR spectra plus pH values improved the prediction of glyphosate sorption capacity ( R2 = 0.88, RMSECV = 34 L kg−1). The models obtained from vis–NIR spectra successfully predicted Kd within the investigated field, indicating the potential of vis–NIR spectroscopy as a fast method for determining Kd for input to leaching risk assessment models. However, further studies of different soil types and geographical scales are needed to confirm our findings.

Electrode-electrolyte interface characterization of carbon electrodes in Li-O2 batteries: capabilities and limitations of infrared spectroscopy

Li-O2 battery electrodes based on amorphous carbon materials were analyzed by ex situ Fourier transform infrared (FTIR) spectroscopy for products formed at the electrode-electrolyte interface during electrochemical cycling against metallic lithium. This analysis shows that FTIR spectroscopy offers several valuable capabilities. First it identifies lithium oxygen species and lithium carbonate as the major species observable on the cycled electrodes. Second it shows that the lithium oxygen species are both formed and partially decomposed electrochemically during discharge and recharge, respectively. Third it reveals that lithium carbonate is mainly formed by irreversible chemical conversion of lithium oxygen species upon air exposure. The limitations of FTIR spectroscopy in the context of electrode-electrolyte interface characterization in Li-O2 batteries become apparent in experiments on positive electrodes featuring different electrochemically active surface areas as well as on blends containing amorphous carbon, and different quantities of lithium peroxide or lithium carbonate. These experiments show that the matrix into which a given analyte is embedded has a marked effect on the detectability of this analyte. Accordingly, the practical detection limit for lithium carbonate is found to increase from 0.4mol% inside a matrix of KBr to > 6mol% inside a matrix of amorphous carbon. Realizing that virtually all other potential product species have lower extinction coefficients than Li2CO3 in the IR spectral range, this suggests that FTIR spectroscopy with a bench top spectrometer is only viable for the study of interface species embedded in amorphous carbon matrices if these species are present in quantities amounting to at least several mol% with respect to the carbonaceous material.

Evaluation of a commercially available passively Q-switched Nd:YAG laser with LiF:[formula omitted] saturable absorber for laser-induced breakdown spectroscopy

Interest in passively Q-switched microchip lasers as a means for miniaturization of laser-induced breakdown spectroscopy (LIBS) apparatus has rapidly grown in the last years. To explore the possibility of using a comparatively UV–vis transparent absorber, we herein present the first report on the evaluation of a commercially available flash lamp-pumped passively Q-switched Nd:YAG laser with LiF:F2- saturable absorber as an excitation source in LIBS. Quantitative measurements of barium, strontium, rubidium and lithium in granite, rhyolite, basalt and syenite whole-rock glass samples were performed. Using a gated intensified benchtop spectrometer, limits of detection of 0.97, 23, 37, and 144ppm were obtained for Li, Sr, Rb, and Ba, respectively. Finally, we discuss the advantages of using such a laser unit for LIBS applications in terms of ablation efficiency, analytical performances, output energy, and standoff capabilities.

Abstract 2011: Feasibility of serum proteomic companion diagnostic (CDx) test development on the microflex LT platform

Abstract Clinical oncology assays using mass spectrometry have exclusively been run on instrument platforms designed for use in research laboratories. Here, we report on the use of a bench-top MALDI-TOF mass spectrometer (MS) to run a serum proteomic Laboratory Developed Test (LDT), VeriStrat®. A number of previous studies have shown that this assay measures a serum proteomic fingerprint using MALDI-TOF MS which, following spectral acquisition and data processing, classifies advanced non-small cell lung cancer (NSCLC) patients into treatment categories. An extension of VeriStrat, BDX004, is currently under development as part of a global, randomized, double-blind Phase 2 clinical study, FOCAL. BDX004 will be used prospectively to select previously untreated, EGFR mutation-positive patients with advanced NSCLC to receive one of two treatments: (1) the combination of ficlatuzumab (a humanized monoclonal antibody against hepatocyte growth factor) and an EGFR tyrosine kinase inhibitor (TKI), or (2) an EGFR TKI with placebo. For the development of BDX004 as a companion diagnostic (CDx), we have included the microflex™ LT (LT), a component of Bruker's MALDI Biotyper CA system, which was granted FDA clearance for the identification of Gram negative bacteria. In the present study, we evaluated the LT platform through comparative studies with other MALDI-TOF instruments (autoflex™ III and autoflex SPEED) utilizing samples from patients previously diagnosed with NSCLC. In summary, we found that under common laboratory procedures the LT produces results equivalent to research grade MALDI-TOF MS instrumentation. In initial studies, the microflex LT showed similar resolution (R &amp;gt; 600 at 6632.1 m/z) and sensitivity (S/N ≥ 50 with 500 fmoles BSA in 100 laser shots) performance parameters as the autoflex series research instruments (R &amp;gt; 800 at 6632.1 m/z and S/N ≥ 50 with 500 fmoles BSA in 250 laser shots). The LT was qualified with several independent sample sets [n = 4 (8 replicates; 2000 spectra/replicate); n = 67 (3 replicates; 2000 spectra/replicate) and n = 20 (3 replicates; 2000 spectra/replicate)]. In these studies, the LT achieved 100%, &amp;gt;97%, and 100% concordance with reference data sets previously acquired on the autoflex platforms. As expected, due to the lower laser repetition rate of the LT's nitrogen laser, the acquisition speed was slower on the LT as compared to the autoflex instruments by a factor of two. However, the slower acquisition speed is partially compensated for with increased sensitivity, which is particularly evident in the reference sample mass spectra which have signal-to-noise ratios ∼1.5 greater than those acquired on the autoflex platform. Based on these results, the microflex LT appears to be suitable for measurement of serum proteomic profiles in NSCLC and suggests that the inclusion of the microflex LT in CDx test development has the potential to expand the utility of MALDI-based testing in the clinic. Citation Format: Nicholas Dupuis, Jamie Chang, Maximillian Steers, Zhigang Weng, Jeno Gyuris, Gary Pestano. Feasibility of serum proteomic companion diagnostic (CDx) test development on the microflex LT platform. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2011. doi:10.1158/1538-7445.AM2015-2011

Rapid screening of 35 new psychoactive substances by ion mobility spectrometry (IMS) and direct analysis in real time (DART) coupled to quadrupole time-of-flight mass spectrometry (QTOF-MS).

The recent propagation of new psychoactive substances (NPS) has led to the development of new techniques for the rapid characterization of controlled substances in this category. A commercial bench-top ion mobility spectrometer (IMS) with a (63) Ni ionization source and a direct analysis in real time (DART) coupled to quadrupole time-of-flight (QTOF) were used for the rapid characterization of 35 NPS. The advantages of these techniques are fast response, ease of operation, and minimal sample preparation. The characteristic reduced mobilities of each substance are reported as are the mass spectra of the 35 compounds. The acquired product ion scan mass spectra were also compared to a library database constructed by QTOF with a electrospray ionization (ESI) source and showed a consistent relative abundance for each peak over time. A total of four seized drug samples provided by the local forensic laboratory were analyzed in order to demonstrate the utility of this approach. The results of this study suggest that both IMS and DART-QTOF are promising alternatives for the rapid screening and characterization of these new psychoactive substances.

Evaluation of four NIR spectrometers in the analysis of cattle slurry

The composition of animal slurries is basic information required to arrange fertilisation plans that allow satisfactory crop yields and avoid environmental pollution. Slurry management based on measured composition data requires the development and adoption of analytical methods that are rapid, affordable and applicable directly in the field. NIR spectroscopy is a candidate technique for this application. In the present work, the performances of four NIR spectrometers, differing in optics, detectors and price, were investigated and compared: one FT-NIR and one dispersive benchtop instrument; a less expensive diode array dispersive instrument also suitable for online applications; and a low-cost interferometric portable instrument. Ninety-nine slurries, collected from livestock farms in Lombardy (Italy), were characterised using reference methods for dry matter (DM), ashes (ASH), total nitrogen (TKN), ammonium nitrogen (AN), organic nitrogen (ON), total carbon (TC) and total phosphorus (TP) content, and were used to investigate the performance of the four NIR spectrometers. The calibrations obtained from the two benchtop instruments for DM, ASH, TKN and TC were classified “useful” or “moderately useful”, while for AN and TP they were “useful for screening purposes”. The two portable instruments provided less accurate calibrations, with the exception of DM and TC which, in the case of the diode array instrument, performed similarly to the benchtop spectrometers. The higher resolution and, to a lesser degree, the wider spectral range of the two benchtop spectrometers contribute to explain their better calibration performances for TKN and AN.

Real-time reaction monitoring by ultrafast 2D NMR on a benchtop spectrometer.

Reaction monitoring is widely used to follow chemical processes in a broad range of application fields. Recently, the development of robust benchtop NMR spectrometers has brought NMR under the fume hood, making it possible to monitor chemical reactions in a safe and accessible environment. However, these low-field NMR approaches suffer from limited resolution leading to strong peak overlaps, which can limit their application range. Here, we propose an approach capable of recording ultrafast 2D NMR spectra on a compact spectrometer and of following in real time reactions in the synthetic chemistry laboratory. This approach--whose potential is shown here on a Heck-Matsuda reaction--is highly versatile; the duration of the measurement can be optimized to follow reactions whose time scale ranges from between a few tens of seconds to a few hours. It makes it possible to monitor complex reactions in non-deuterated solvents, and to confirm in real time the molecular structure of the compounds involved in the reaction while giving access to relevant kinetic parameters.

60 MHz卓上NMR装置を用いる有機化合物の純度測定の検討

Since quantitative values on the basis of a nucleus can be obtained by nuclear magnetic resonance (NMR) spectroscopy, the quantitative NMR technique requires no identical standard. For this reason, it is expected to be a universal quantitative method. However, the quantification using an NMR requires a high resolution NMR spectrometer in NMR measurement. In this paper, we discuss the quantitative NMR method using a benchtop NMR spectrometer with a low magnetic field. We studied the conditions of NMR measurement and data process. The precision of the result was evaluated with approximately 1% using a benchtop spectrometer. Especially, the low S/N and large FWHS of the NMR signals caused low repeatability.

Use of handheld mid-infrared spectroscopy and partial least-squares regression for the prediction of the phosphorus buffering index in Australian soils

The development of techniques for the rapid, inexpensive and accurate determination of the phosphorus (P) buffer index (PBI) in soils is important in terms of increasing the efficiency of P application for optimum crop requirements and preventing environmental pollution due to excessive use of P fertilisers. This paper describes the successful implementation of partial least-squares regression (PLSR) from spectra obtained with bench-top and handheld mid-infrared (MIR) spectrometers for the prediction of PBI on 601 representative Australian agricultural soils. By contrast, poor predictions were obtained for available (Colwell) P. Regression models were successfully derived for PBI ranges of 0–800 and 0–150, the latter range resulting in the optimum model considering the dominance of low PBI soils in the sample set. Concentrations of some major soil minerals (mainly kaolinite and gibbsite content for high PBI, and smectites or illites for low PBI), quartz (representative of low surface area of soils) and, to a lesser extent, carbonate and soil organic matter were identified as the main drivers of the PBI models. Models developed with soils sieved to &lt;2 mm presented an accuracy similar to those developed using fine-ground material. The accuracy of the PLSR for the prediction of PBI by using bench-top and handheld instruments was also similar. Our results confirm the possibility of using MIR spectroscopy for the onsite prediction of PBI.

Parahydrogen discriminated PHIP at low magnetic fields

Parahydrogen induced polarization (PHIP) is a powerful hyperpolarization technique. However, as the signal created has an anti-phase characteristic, it is subject to signal cancellation when the experiment is carried out in inhomogeneous magnetic fields or in low fields that lack the necessary spectral resolution. The use of benchtop spectrometers and time domain (TD) analyzers has continuously grown in the last years and many applications are found in the food industry, for non-invasive compound detection or as a test bench for new contrast agents among others. In this type of NMR devices the combination of low and inhomogeneous magnetic fields renders the application of PHIP quite challenging. We have recently shown that the acquisition of J-spectra in high magnetic fields not only removes the anti-phase peak cancellation but also produces a separation of thermal from hyperpolarized signals, providing Parahydrogen Discriminated (PhD-PHIP) spectra. In this work we extend the use of PhD-PHIP to low and inhomogeneous fields. In this case the strong coupling found for the protons of the sample renders spin-echo spectra that have a great complexity, however, a central region in the spectrum with only hyperpolarized signal is clearly identified. This experimental approach is ideal for monitoring real time chemical reaction of pure PHIP signals.

Preface to Special Topic: Selected Papers from the Advances in Microfluidics and Nanofluidics 2014 Conference in Honor of Professor Hsueh-Chia Chang's 60th Birthday.

Preface to Special Topic: Selected Papers from the Advances in Microfluidics and Nanofluidics 2014 Conference in Honor of Professor Hsueh-Chia Chang's 60th Birthday.

A portable lab-on-a-chip system for gold-nanoparticle-based colorimetric detection of metal ions in water.

Heavy metal ions released into various water systems have a severe impact on the environment and human beings, and excess exposure to toxic metal ions through drinking water poses high risks to human health and causes life-threatening diseases. Thus, there is high demand for the development of a rapid, low-cost, and sensitive method for detection of metal ions in water. We present a portable analytical system for colorimetric detection of lead (Pb(2+)) and aluminum (Al(3+)) ions in water based on gold nanoparticle probes and lab-on-a-chip instrumentation. The colorimetric detection of metal ions is conducted via single-step assays with low limits of detection (LODs) and high selectivity. We design a custom-made microwell plate and a handheld colorimetric reader for implementing the assays and quantifying the signal readout. The calibration experiments demonstrate that this portable system provides LODs of 30 ppb for Pb(2+) and 89 ppb for Al(3+), both comparable to bench-top analytical spectrometers. It promises an effective platform for metal ion analysis in a more economical and convenient way, which is particularly useful for water quality monitoring in field and resource-poor settings.

Biosensors based on porous cellulose nanocrystal-poly(vinyl alcohol) scaffolds.

Cellulose nanocrystals (CNCs), which offer a high aspect ratio, large specific surface area, and large number of reactive surface groups, are well suited for the facile immobilization of high density biological probes. We here report functional high surface area scaffolds based on cellulose nanocrystals (CNCs) and poly(vinyl alcohol) (PVA) and demonstrate that this platform is useful for fluorescence-based sensing schemes. Porous CNC/PVA nanocomposite films with a thickness of 25-70 nm were deposited on glass substrates by dip-coating with an aqueous mixture of the CNCs and PVA, and the porous nanostructure was fixated by heat treatment. In a subsequent step, a portion of the scaffold's hydroxyl surface groups was reacted with 2-(acryloxy)ethyl (3-isocyanato-4-methylphenyl)carbamate to permit the immobilization of thiolated fluorescein-substituted lysine, which was used as a first sensing motif, via nucleophile-based thiol-ene Michael addition. The resulting sensor films exhibit a nearly instantaneous and pronounced change of their fluorescence emission intensity in response to changes in pH. The approach was further extended to the detection of protease activity by immobilizing a Förster-type resonance energy transfer chromophore pair via a labile peptide sequence to the scaffold. This sensing scheme is based on the degradation of the protein linker in the presence of appropriate enzymes, which separate the chromophores and causes a turn-on of the originally quenched fluorescence. Using a standard benchtop spectrometer to monitor the increase in fluorescence intensity, trypsin was detected at a concentration of 250 μg/mL, i.e., in a concentration that is typical for abnormal proteolytic activity in wound fluids.

The use of different dispersive Raman spectrometers for the analysis of uranium compounds

The performances of three different Raman spectrometers were compared and evaluated as a suitable tool for the analysis of a range of uranium compounds with a view to application in nuclear forensics. These included uranium ore concentrates of different chemical composition and uranium dioxide in the form of powder and sintered fuel pellet. The three spectrometers are termed as ‘portable’ or ‘hand-held’ from Ahura Scientific (785nm), ‘Senterra’ from Bruker (532 and 785nm), ‘T64000′ from HORIBA Jobin Yvon (488.0, 514.5, 647.1 and 752.5nm). Figures of merit such as sensitivity, signal-to-noise ratio and detection capability were compared. The portable Raman displayed fairly good sensitivity and process related impurities could be detected despite the miniaturisation but it was unable to measure darkly coloured powders such as calcined ore concentrates or uranium dioxide powder. The bench-top spectrometer Senterra had the best sensitivity for all the seven measured uranium compounds and the best signal-to-noise ratio for six of the compounds. Laboratory T64000 had the best resolution and at the same time resulting in the poorest sensitivity among the three spectrometers for all compounds measured. However, T64000 has very low level of noise therefore leading to better signal-to-noise that were comparable, if not better than the portable or Senterra. All industrial compounds measured in this study could not be measured with higher frequency laser thus impeding the observation of N–H or O–H vibration bands, of which the latter could be observed with laboratory synthesized material.

Evaluation of surface-enhanced Raman scattering detection using a handheld and a bench-top Raman spectrometer: A comparative study

Surface enhanced Raman scattering (SERS) detection using a handheld Raman spectrometer and a bench-top Raman spectrometer was systemically evaluated and compared in this study. Silver dendrites were used as the SERS substrate, and two pesticides, maneb and pyrrolidine dithiocarbamate-ammonium salt (PDCA) were used as the analytes. Capacity and performance were evaluated based on spectral resolution, signal variation, quantitative capacity, sensitivity, flexibility and intelligence for SERS detection. The results showed that the handheld Raman spectrometer had better data consistency, more accurate quantification capacity, as well as the capacity of on-site and intelligence for qualitative and semi-quantitative analysis. On the other hand, the bench-top Raman spectrometer showed about 10 times higher sensitivity, as well as flexibility for optimization of the SERS measurements under different parameters such as laser power output, collective time, and objective magnification. The study on the optimization of SERS measurements on a bench-top spectrometer provides a useful guide for designing a handheld Raman spectrometer, specifically for SERS detection. This evaluation can advance the application of a handheld Raman spectrometer for the on-site measurement of trace amounts of pesticides or other chemicals.