Handheld near-infrared spectrometers: Where are we heading?

Abstract

During NIR 2019 conference, Gold Coast, Australia, a presentation upon a critical review of instrumentation and applications of handheld spectrometers was delivered during the plenary session held on Thursday morning, 19 September. Following the conference presentation, a vivid discussion flared up among the audience that equally involved academic scholars, industry representatives, as well as professionals who carry out every day in-the-field applications. Various aspects were raised connected with the emerged new generation of near-infrared instrumentation, with many individuals expressing their point-of-view on the merits and pitfalls of the miniaturized spectrometers. This vigorous dispute and exchange of impressions indicated that the community remains concerned about the applicability of such devices. That concern reflects the still relatively shallowly explored miniaturization versus performance factor, which can only be dismissed by focused feasibility studies with comparative analyses carried out on scientific-grade benchtop spectrometers. It is the aim of the present manuscript to summarize the discussed scientific content and to share the developed point-of-view with addition of our remarks.

Full text

Original Article
Handheld near-infrared spectrometers:
Where are we heading?
Krzysztof B Be
c
1
, Justyna Grabska
1
, Heinz W Siesler
2
and
Christian W Huck
1
Abstract
During NIR 2019 conference, Gold Coast, Australia, a presentation upon a critical review of instrumentation and applications
of handheld spectrometers was delivered during the plenary session held on Thursday morning, 19 September. Following
the conference presentation, a vivid discussion flared up among the audience that equally involved academic scholars,
industry representatives, as well as professionals who carry out every day in-the-field applications. Various aspects were
raised connected with the emerged new generation of near-infrared instrumentation, with many individuals expressing
their point-of-view on the merits and pitfalls of the miniaturized spectrometers. This vigorous dispute and exchange of
impressions indicated that the community remains concerned about the applicability of such devices. That concern reflects
the still relatively shallowly explored miniaturization versus performance factor, which can only be dismissed by focused
feasibility studies with comparative analyses carried out on scientific-grade benchtop spectrometers. It is the aim of the
present manuscript to summarize the discussed scientific content and to share the developed point-of-view with addition of
our remarks.
Keywords
Handheld, portable, near-infrared instrumentation, application, evaluation, miniaturization versus performance
Introduction
It is commonly accepted to divide the fieldable spec-
trometers (i.e. deployable in-the-field, in contrast to
benchtop instrumentation, that is only applicable in a
laboratory setting) into transportable (e.g. deployable
on field while mounted in a car), portable in ‘suitcase’
format (>4 kg of total equipment weight) and hand-
held (<1 kg) ones.
1
These criteria suit the broadly
understood spectroscopy and spectrometry, including
e.g. elemental (atomic) techniques such as X-ray fluo-
rescence or laser-induced breakdown spectroscopy,
and even mass spectrometry (MS) or nuclear magnetic
resonance. When considering purely this sole factor,
NIR spectroscopy enjoys a fair advantage over several
other techniques in its compact technology. The most
recent years have brought ultra-miniaturized NIR
spectrometers to reality; such devices are either USB
powered or have own built-in battery, weigh less than
50 g and can be operated by an application installed on
a smartphone. The progress in miniaturization is
accompanied by software development aimed at ease
of use and suitability for operation by a non-expert
consumer community. Qualitative differences in the
level of sensor miniaturization achieved over the past
few decades in different fields of spectroscopy and
spectrometry are demonstrated in Figure 1.
While some other physicochemical methods of anal-
ysis reached similarly impressive levels of miniaturiza-
tion (e.g. fluorescence), NIR spectroscopy still offers
superior chemical specificity and applicability to a
broad range of sample types.
Searching for ‘portable near-infrared spectroscopy’
in ISI Web of Science database (https://apps.webof
knowledge.com) results in 239 publications since 2005
with increasing tendency (Figure 2(a)). The total
number of citations since 2005 is 2512 and from the
graph depicted in Figure 2(b) the highly increasing
number on a yearly basis can be deduced. From this
statistics, it is obvious that portable NIR spectroscopy
is an efficient and popular analytical chemistry tech-
nique. Current technological progress enables new
advance in miniaturization and there is no doubt that
1
Institute of Analytical Chemistry and Radiochemistry, CCB – Center for
Chemistry and Biomedicine, Innsbruck, Austria
2
Department of Physical Chemistry, University of Duisburg-Essen, Essen,
Germany
Corresponding author:
Christian W Huck, Institute of Analytical Chemistry and Radiochemistry,
CCB – Center for Chemistry and Biomedicine, Innrain 80/82, Innsbruck
6020, Austria.
Email: Christian.W.Huck@uibk.ac.at
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Figure 1. Various level of transportability of spectrometers. (a) Car-transportable GC–MS and long-path reflective FT-IR instrumentation,
(b) portable tunable diode-laser absorption spectroscopy (TDLAS) sensor mounted on a height-adjustable tripod, (c) Agilent 4300
Handheld FT-IR spectrometer and (d) miniaturized USB-powered NIR spectrometer Viavi MicroNIR Pro ES 1700. Source: Panel (a)
reproduced from Eckenrode
2
with permission under Elsevier Open Access license. Panel (b) reproduced from Zhang et al.
3
under CC-BY
4.0 license. Panel (c) reproduced from Hutengs et al.
4
under CC-BY 4.0 license.
Figure 2. Number of (a) publications and (b) citations of ‘portable near-infrared spectroscopy’ since 2005 according to Web of Knowledge
database.
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handheld NIR spectrometers belong to the next gener-
ation of analytical instrumentation. More and more
they are suitable to become a technology of choice
not only in industry but also in everyday life
applications.
There are several fields of application, which strong-
ly depend on maturing miniaturized spectroscopy as a
robust analytical tool – one of such fields is the agro-
food sector. European Commission stresses the prime
importance of food analysis for the public safety.
5
In
2015, the European Union opened a challenge on
‘health, demographic chance and wellbeing’ to reward
solutions, intended for the general public, that allow to
analyse and secure food quality including allergen rec-
ognition. Thus, in 2017 at the CeBIT Exhibition in
Hannover, Germany, three companies were awarded
and shared 1 million e: 800,000 efor the winner,
Spectral Engines (Spectral Engines Oy, Helsinki,
Finland), and 100,000 e, each, for the two runners-
up, SCiO (Consumer Physics, Tel Aviv, Israel) and
Tellspec (Tellspec Inc., Toronto, Canada). These
three instruments have in common that they are (i)
cheap, (ii) portable, (iii) handheld, (iv) applicable to
fulfil the requested aim and (v) rely on internet-of-
things and cloud computing to enable communication
and to facilitate their use. At this point, it must be
noted that these companies are not the only ones at
the market, which will be discussed later.
It is a natural course to promote new technologies
capable of improving everyone’s life. Miniaturized
NIRS is one of the first methods of analytical chemis-
try that reached out to the level of ordinary consumers.
There is of course a great and unique potential in such
a trend. However, it becomes apparent that some
attempts to take shortcuts appeared. The community
gathered at the International NIR 2019 conference has
become well aware of the hazard resulting from rapidly
increasing use of NIR sensors in general public, which
we will outline at the end of this article. However, first
it is necessary to summarize the essentials of portable
NIR spectroscopy, the instrumental basis and the
applicability of the latest generation of handheld NIR
spectrometers. Only on such background, the major
point of the community’s concern can be expressed
comprehensively.
The principles of the technology leading to
miniaturized NIR spectroscopy
Best strategy for discussing the design of handheld
NIR spectrometers is to divide up the optical spectrum
by detector technology.
1
Detectors
In the silicon detector region, we have low cost 1D
and 2D array sensors, and therefore multichannel
techniques are dominating. Complementary metal–
oxide–semiconductor (CMOS) technology has been
gaining steadily on charge-coupled device, mainly
driven by developments in smartphones and cameras,
with CMOS requiring lower power consumption.
1
At
wavelengths longer than approximately 1050 nm,
indium–gallium–arsenide (InGaAs) detectors dominate
and have substituted both Germanium (Ge) and lead
salt detectors (lead sulphide (PbS) and lead selenide
(PbSe)), with lead salt single point detectors being
still available on the market. For miniaturized NIR
spectrometers, cost and power consumption are
major drivers. Therefore, single element detectors are
preferred showing the disadvantage of being noisier
than standard InGaAs (1700 nm cut-off) and require
cooling.
Wavelength selectors
Micro-electro-mechanical systems (MEMSs; if com-
bined with micro-optics then referred to as micro-
opto-electro-mechanical systems, i.e. optical MEMS
or MOEMS) enable constructing micro-scaled complex
mechanical devices directly in-silicon using various
techniques established in semiconductor industry for
chip manufacturing. MEMS-based spectrometers
have been proposed almost 20 years ago, including
Fourier transform (FT) spectrometers. In the case of
the latter, the key component is a resonantly driven
micro-mirror, suspended on two long springs, and
driven by interlocking comb-structured electrodes.
About a decade ago, it was expected that MEMS spec-
trometers would be rapidly commercialized, but this
fact did not become true.
1
A key issue in this context
is the size of the optics and the ability of an MEMS
comb actuator to drive the moving mirror. The com-
mercially successful handheld FT-IR spectrometer
from Thermo Fisher Scientific uses a voice-coil and
piston-bearing scheme, with a 1.2 cm diameter
moving mirror, which is essentially a scaled-down ver-
sion of conventional laboratory interferometers.
Compared to mid-IR, NIR sources are brighter and
detectors have a higher specific detectivity D*, so that
the issue of mirror size is mitigated in NIR instruments.
Between 2017 and 2020, NeoSpectra, the commercial
arm of Si-Ware Systems, has launched several MEMS
FT-NIR sensors/scanners that are based on the same
optical principle (the first and the latest product are
shown in Figure 3(e)).
A Hadamard spectrometer is a multiplex device that
observes more than one wavelength at a time using one
or two masks instead of slits. This spectrometer offers
both a Jacquinot and a multiplex advantage. In a single
mask design spectrometer, light passes from the source
through a sample and onto the entrance slit of a spec-
trograph; it is dispersed by a grating. Then, the encod-
ing mask selects 50% of the resolution elements and
passes that light onto a single element detector. A typ-
ical mask is an array of zeros and ones. The position of
the zeros and ones on the mask changes and the detec-
tor is read out for each of these positions. Typically,
Be
c et al. 3

the mask uses a cyclic S-matrix sequence, in which each
row is obtained by shifting the previous row one posi-
tion to the left. At the end of data collection, a simple
matrix transform recovers the spectrum from the col-
lected data. A handheld NIR spectrometer, using an
MEMS chip as the Hadamard encoding device, has
been commercially available since 2007 (Figure 3(a)).
The Hadamard mask is a programmable MEMS dif-
fraction grating, originally developed as key element in
a programmable correlation spectrometer for remote
detection and is included in a spectrometer for
NASA to determine water content on the surface of
the moon.
Almost 20 years ago, the use of a digital light pro-
jector as a Hadamard mask was described. Texas
Instruments’ DLP is probably the most common
MEMS device. Texas instruments offers two NIR
engines: DLP NIRscan and DLP NIRscan Nano, as
evaluation modules (EVMs) (Figure 3(c)). To achieve a
micro-scaled programmable Hadamard mask, the DLP
devices use MEMS-based digital micromirror device
(DMD), while Thermo Fischer design microPHAZIR
employs MEMS piano-like diffraction grating in its
implementation of the Hadamard principle.
Application of Hadamard transformation enables con-
structing compact cost-effective spectrometers with a
single-pixel photodetector operating at any wave-
length. An MEMS-driven moving mask is used to
encode the light intensity at its imaging slit, which is
then collected by a single-pixel detector. Afterwards,
the spectrum is obtained through an inverse
Hadamard transform.
6
Fabry–Perot interferometers are playing a dominant
role as a wavelength separation technique since about
Figure 3. Principles of wavelengths selectors built into different handheld NIR spectrometers: (a) MEMS Hadamard mask – microPHAZIR,
Thermo Fisher Scientific, Waltham, USA; (b) LVF –MicroNIR Pro ES 1700, VIAVI, Santa Rosa, USA; (c) MEMS DMD – implementation
of DLP NIRscan module, Texas Instruments, Dallas, USA; (d) MEMS Fabry–Perot interferometer – NIRONE Sensor S, Spectral Engines,
Helsinki, Finland; (e) MEMS Michelson interferometer – NeoSpectra, Si-Ware, Cairo, Egypt; (f) MEMS Michelson interferometer with
a large mirror – nanoFTIR NIR, SouthNest Technology, Hefei, China. ADC: analog-to-digital converter; InGaAs: indium–gallium–arsenide;
MEMS: micro-electro-mechanical system.
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25 years. A Fabry–Perot filter consists of two mirrors,
either plane or curved, facing each other and separated
by a distance d. There are two basic versions: an inter-
ferometer, where d is variable, and an etalon, where d is
fixed. The condition for constructive interference with a
Fabry–Perot interferometer is that the light forms a
standing wave between the two mirrors, in which case
the optical distance between the two mirrors must equal
an integral number of half wavelengths of the incident
light. A Fabry–Perot interferometer may be also imple-
mented through MEMS-technology, e.g. as it is used in
NIRONE Sensor S device. Thus, MEMS technology
enables to implement as a fully programmable optical
filter in the form of a micro-scale module.
Linear variable filters (LVFs) are optical bandpass
filters that have been wedged in one direction; the
thickness of the coating is not constant across the fil-
ters. The transmitted wavelength varies linearly across
the filter. A LVF can be thought of as a scanning
Fabry–Perot filter which scans the position across the
filter. The typical range is one octave. Ocean Optics
mid-infrared spectrometer has a nine-reflection ATR
interface and covers the wavenumber range 1818–
909 cm
1
at 75 cm
1
resolution, with a nominal S/N
ratio of 300:1. For NIR spectroscopy, the LVF tech-
nology is of interest for the following reasons: It is low
cost, very compact, rugged, satisfying spectral resolu-
tion for real applications, and low power consumption.
For example, VIAVI has a line of handheld and pro-
cess spectrometers based on LVF and InGaAs array
(Figure 3(b)).
In the silicon detector region, a number of filter tech-
nologies compete: LVFs and mosaic, patterned, and dis-
crete filters. Consumer Physics released a spectroscopic
product called SCiO, with dimensions of 67.7 mm 
40.2 mm 18.8 mm and weight of 35 g. It consists of a
43 photodiode array, with optical filters over the indi-
vidual pixels. The device has only 12 resolution elements
resulting in a rather poor spectral resolution of ca. 28 nm
across its working spectral region of 740–1070nm
(13,514–9346 cm
1
). The absorption properties of numer-
ous samples in the visible/short-wave NIR should also be
considered as a limiting factor here. It becomes apparent
that this design accepted a number of compromises in
order to achieve its compact factor and low cost.
The instrumental development continues, and
almost every year new concepts and products are intro-
duced to the market of miniaturized NIRS. Some of
the engineering principles are being refined as well. As
a good example serves here the concept of Michelson
interferometer implemented in MEMS technology. The
difficulties with maintaining stable operation of the
MEMS elements and the optical throughput could
have been challenged recently. This technology was
introduced as the final products in NIRONE sensors
from Spectral Engines and nanoFTIR NIR spectrom-
eter from SouthNest Technology. The latter is one of
the most recent miniaturized NIR sensors; it imple-
ments an MEMS Michelson interferometer with a
large mirror (in relation to MEMS chip) in order to
improve the light output. This device operates over the
entire NIR wavelength region (12,500–3846 cm
1
;
800–2600 nm), which stands in contrast to most other
handheld spectrometers including the earlier MEMS-
based portable NIR sensors (Table 1). According to
the information provided by the vendor, in addition
to a very broad working spectral region, the sensor
offers higher (although still inferior to benchtops) spec-
tral resolution of 6 nm at 1600nm, high SNR and rapid
scanning, while being far more compact (143 mm 
49 mm 28 mm dimensions and 220 g weight) than
early MEMS spectrometers. However, how these
Table 1. Spectral regions and spectral resolution in which the discussed handheld NIR spectrometers operate.
Spectrometer
Spectral resolution
Spectral resolution
(at wavelength)
a
(nm)(nm) (cm
1
)
microPHAZIR (Thermo Fisher Scientific) 1596–2396 6267–4173 11
MicroNIR Pro ES 1700 (VIAVI) 908–1676 11,013–5967 12.5 (at 1000)
25 (at 2000)
SCiO (Consumer Physics) 740–1070 13,514–9346 Unknown
b
NIRscan (Texas Instruments) 900–1700 11,111–5882 10
NIRONE Sensors (Spectral Engines) 1100–1350 9091–7407 12–16
1350–1650 7407–6061 13–17
1550–1950 6452–5128 15–21
1750–2150 5714–4651 16–22
2000–2450 5000–4082 18–28
c
NeoSpectra (Si-Ware Systems) 1350–2500 7407–4000 16 (at 1550)
nanoFTIR NIR (SouthNest Technology) 800–2600 12,500–3846 2.5 (at 1000)
6 (at 1600)
13 (at 2400)
NIR: near-infrared.
a
‘At wavelength’ parameter listed if available in the data-sheet provided by the vendor.
b
SCiO presents to the operator interpolated spectra with 1 nm data-spacing, but the real resolution is considerably lower.
c
Depending on the sensor implementation/factory configuration.
Be
c et al. 5

promising data-sheet entries translate into the
real-world analytical performance remains to be eval-
uated through peer-reviewed research.
Application and in-depth evaluation of
performance characteristics of portable
NIR spectrometers
The contemporary benchtop spectrometers implement
a long-matured technology and over the past decades
those devices converged almost to a generic FT-NIR
design differing mostly by subtle nuances, at least from
the application point-of-view. In sharp contrast, vari-
ous technology concepts have been implemented into
portable NIR instrumentation in its vigorous develop-
ment over the last 10 years, as briefly outlined in the
‘The principles of the technology leading to miniatur-
ized NIR spectroscopy’ section. Through adoption of
innovative approaches and overcoming engineering
challenges, various handheld NIR sensors have been
brought into the market. However, the progressing
miniaturization unavoidably influenced the working
characteristics (e.g. sensitivity and S/N, spectral
region, spectral resolution) and the resulting analytical
performance of such spectrometers in relation to the
benchtop ones. Furthermore, the vendors often took
upon completely different engineering directions
when designing their portable instruments. Therefore,
several research groups recognized the need for per-
forming comprehensive research studies aimed at
establishing the applicability limits of handheld NIR
spectroscopy. As a good example, Hoffman et al.
7
explored the transferability of spectral sets, as well as
qualitative and quantitative calibrations that have been
developed thereof, between NIR spectroscopy in
benchtop and portable scenario. Miniaturized spec-
trometers demonstrate a particular potential for the
analysis of natural products outside laboratories. In
2017, for instance, Kirchler et al.
8
investigated the fea-
sibility of using portable NIRS to determine the con-
tent of the anti-oxidative active ingredients (rosmarinic
acid and closely related polyphenols) in medicinal
plants. They compared the working characteristics
and the final analytical performance of two handheld
spectrometers exemplifying distinctly different design
philosophies and levels of miniaturization. The study
was based on the comparison with a reference bench-
top NIR spectrometer (high-performance Bu
¨chi
Figure 4. Identification performance of different types of handheld NIR spectrometers for the recycling of polymer commodities. Top row:
3D score plots of the PCA calibration. Bottom row: fit of test samples (•) into calibration plots. PE: polyethylene; PET: polyethylene
terephthalate; PP: polypropylene; PS: polystyrene; PVC: polyvinyl chloride. Reproduced from Ref. 11.
6NIR news 0(0)

NIRFlex N-500) and supported by exhaustive
data-analytical tools, including hetero-correlated 2D
plots that highlighted the differences between the
NIR spectra measured on the three spectrometers.
Further exploration of the potential of miniaturized
NIR sensors in quantitative assessment of the antioxi-
dant capacity of natural-borne products was demon-
strated by Wiedemair and Huck.
9
In that case, the total
of three different miniaturized NIR devices was evalu-
ated towards their performance in assessing gluten-free
grains. Performance comparisons of different handheld
near-infrared spectrometers have been performed in
the demanding scenario of quantitative analysis of a
pharmaceutical formulation as well, e.g. by Yan and
Siesler.
10
However, the discussed problem is essential in var-
ious other fields of research and analysis. Yan and
Siesler
11
studied the identification performance of dif-
ferent types of handheld NIR spectrometers for the
recycling of polymer commodities, including polyeth-
ylene (PE), polypropylene, polyethylene terephthalate,
polyvinyl chloride (PVC) and polystyrene. Four differ-
ent handheld spectrometers based on different mono-
chromator principles were investigated: Si-Ware
systems, Spectral Engines NR 2.0 W; DLP NIRscan
Nano EVM, and Viavi MicroNIR Pro ES 1700. The
investigation clearly demonstrated that the spectra of
the most common polymer commodities provide suit-
able analytical measurement parameters for the correct
classification of unknown test samples. Upon perform-
ing principal component analysis (PCA), all polymer
classes could be sufficiently separated, excepting PE
and PVC measured by the Spectral Engines NR
2.0W spectrometer (Figure 4).
Wiedemair et al.
12,13
have tested the performance of
SCiO in comparison with Bu
¨chi NIRFLex N-500 for
the analysis of protein content in millet samples and
the fat content in cheese samples. As can be deduced
from Tables 2 and 3 they found that the analytical
performance of portable devices may considerably
vary between different scenarios. Although clearly infe-
rior in the former analytical problem (Table 2), in the
determination of fat content in cheese (Table 3), the
inexpensive SCiO sensor delivered the performance,
evaluated by statistical values, comparable to the
high-performing benchtop instrument. Several other
examples may be mentioned that clearly demonstrate
the interest that portable NIRS attracts for a variety of
applications, e.g. identification/authentication of tex-
tiles as a measure against counterfeit.
14
This gives pros-
pects for future evolution of applications of
miniaturized NIRS. However, the scientific and profes-
sional community understands that the performance
evaluation of miniaturized spectrometers in different
scenarios needs to remain a continuously explored
direction, as new devices keep appearing on the
market.
The conclusions from the community discussion
at NIR 2019 concerning portable NIRS
The continuous instrumental developments and appli-
cations observed over the last few years have launched
NIR spectroscopy into a new era of on-site and in-the-
field analysis. Generally, popularization of handheld
instruments brings a reasonable prospect for enabling
truly wide scale applications and high volume NIR
spectroscopic analyses in a wide spectrum of scenarios.
Seen through these lenses, a major transformation is
occurring that brings this tool closer to general public
in everyday use. Vendors have succeeded in consider-
ably reducing manufacturing costs of handheld NIR
Table 2. Performance of benchtop versus ultra-portable NIR spectrometer in millet analysis. Parameters of the established PLS-R models
for protein content (7–14% w/w in this sample set).
Spectrometer State of the grains PCs R
2
(CV) RMSECV (mg GAE/g) R
2
(TV) RMSEP (mg GAE/g)
NIRFlex N-500 Intact 4 0.953 0.365 0.940 0.467
Milled 6 0.985 0.223 0.920 0.479
SCiO Intact 5 0.876 0.601 0.814 0.806
Milled 5 0.8240 0.743 0.782 0.840
CV: cross-validated regressions; GAE: gallic acid equivalents; NIR: near-infrared; PC: principal component; PLS-R: Partial Least Squares Regression;
RMSECV: Root Mean Square Error of Cross Validation; RMSEP: Root Mean Square Error of Prediction; TV: test set-validated regressions.
Table 3. Performance of benchtop versus ultra-portable NIR spectrometer in cheese analysis. Parameters of the established PLS-R models
for fat content (9–36% w/w in this sample set).
Spectrometer State of the grains PCs R
2
(CV) RMSECV (mg GAE/g) R
2
(TV) RMSEP (mg GAE/g)
NIRFlex N-500 Intact 2 0.9726 1.5711 0.9431 1.8964
Grated 2 0.9930 0.7845 0.9913 0.7676
SCiO Intact 2 0.9801 1.2466 0.9838 1.1874
Grated 2 0.9838 1.0527 0.9940 0.8194
CV: cross-validated regressions; GAE: gallic acid equivalents; NIR: near-infrared; PC: principal component; PLS-R: Partial Least Squares Regression;
RMSECV: Root Mean Square Error of Cross Validation; RMSEP: Root Mean Square Error of Prediction; TV: test set-validated regressions.
Be
c et al. 7

spectrometers and made great efforts to make these
instruments suitable for everyday life applications by
a non-expert user community. However, caution
should be applied with the instruments advertised by
direct-to-consumer-companies.
The major gathering of the global NIR community
in Gold Coast, Australia in 2019 reflected that aware-
ness. The primary concern expressed by the experts in
the field was the following: miniaturized equipment still
requires comprehensive validation studies performed in
well-equipped laboratories. The need for closer coop-
eration between the vendors and these laboratories
would be beneficial for the adoption of new
technology.
Opportune conditions of the contemporary market
promote overly optimistic and aggressive marketing
strategies, which may bring the opposite effect. At
some point, the customers are likely to attempt to use
NIR spectroscopy in unrealistic scenarios and fail
therein. The resulting crisis of public trust in this tech-
nology may severely harm sales, and thus future devel-
opment. Such scheme can, however, be avoided if a
close cooperation between the vendor companies and
research laboratories is maintained. This summarizes
the ‘take home message’ from the NIRS community,
as resulted from the discussion upon the current state
and future path of miniaturized spectrometers at NIR
2019 conference (Gold Coast, Australia).
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with
respect to the research, authorship, and/or publication of this
article.
Funding
The author(s) disclosed receipt of the following financial sup-
port for the research, authorship, and/or publication of this
article: This work was funded by the Austrian Science Fund
(FWF): M2729-N28.
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