Monitoring a bioprocess for ethanol production using FT-MIR and FT-Raman spectroscopy

The application of Fourier transform mid-infrared (FT-MIR) spectroscopy and Fourier transform Raman (FT-Raman) spectroscopy for process and quality control of fermentative production of ethanol was investigated. FT-MIR and FT-Raman spectroscopy along with multivariate techniques were used to determine simultaneously glucose, ethanol, and optical cell density of Saccharomyces cerevisiae during ethanol fermentation. Spectroscopic measurement of glucose and ethanol were compared and validated with the high-performance liquid chromatography (HPLC) method. Spectral wave number regions were selected for partial least-squares (PLS) regression and principal component regression (PCR) and calibration models for glucose, ethanol, and optical cell density were developed for culture samples. Correlation coefficient (R ²) value for the prediction for glucose and ethanol was more than 0.9 using various calibration methods. The standard error of prediction for the PLS first-derivative calibration models for glucose, ethanol, and optical cell density were 1.938 g/l, 1.150 g/l, and 0.507, respectively. Prediction errors were high with FT-Raman because the Raman scattering of the cultures was weak. Results indicated that FT-MIR spectroscopy could be used for rapid detection of glucose, ethanol, and optical cell density in S. cerevisiae culture during ethanol fermentation. Journal of Industrial Microbiology & Biotechnology (2001) 26, 185–190. Received 16 November 2000/ Accepted in revised form 12 January 2001     

Physicochemical and comparative properties of pectins extracted from Akebia trifoliata var. australis peel

The physicochemical properties of the pectins extracted from Akebia trifoliata var. australis peel with hydrochloric acid and citric acid, namely HEP and CEP, were evaluated as compared with citrus pectin (CP). X-ray diffraction confirmed that CP had more well defined crystal than HEP and CEP. The DE values of HEP, CEP and CP were 59.46%, 76.64% and 71.03%, respectively. CP exhibited the highest viscosity-average molecular weight of 64,848 Da, followed by HEP (45,353 Da) and CEP (28,877 Da). In general, the emulsion activity of HEP and CEP increased as oil concentration was increased, while HEP showed the strongest emulsion activity among the three pectins. Textural analysis demonstrated that the gelling properties of three pectins decreased with increase in pH, and CP displayed superiority in hardness (9.03 g), while CEP was the poorest (1.45 g). All results suggested that A. trifoliata var. australis had the potential in producing pectin for commercial food industry application.     

Raman spectroscopy and chemometrics for on‐line control of glucose fermentation by Saccharomyces cerevisiae

This work presents the use of Raman spectroscopy and chemometrics for on‐line control of the fermentation process of glucose by Saccharomyces cerevisiae. In a first approach, an on‐line determination of glucose, ethanol, glycerol, and cells was accomplished using multivariate calibration based on partial least squares (PLS). The PLS models presented values of root mean square error of prediction (RMSEP) of 0.53, 0.25, and 0.02% for glucose, ethanol and glycerol, respectively, and RMSEP of 1.02 g L^?1 for cells. In a second approach, multivariate control charts based on multiway principal component analysis (MPCA) were developed for detection of fermentation fault‐batch. Two multivariate control charts were developed, based on the squared prediction error (Q) and Hotelling's T². The use of the Q control chart in on‐line monitoring was efficient for detection of the faults caused by temperature, type of substrate and contamination, but the T² control chart was not able to monitor these faults. On‐line monitoring by Raman spectroscopy in conjunction with chemometric procedures allows control of the fermentative process with advantages in relation to reference methods, which require pretreatment, manipulation of samples and are time consuming. Also, the use of multivariate control charts made possible the detection of faults in a simple way, based only on the spectra of the system. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

Assessment of NIR spectroscopy for nondestructive analysis of physical and chemical attributes of sulfamethazine bolus dosage forms

The goal of this study was to assess the utility of near infrared (NIR) spectroscopy for the determination of content uniformity, tablet crushing strength (tablet hardness), and dissolution rate in sulfamethazine veterinary bolus dosage forms. A formulation containing sulfamethazine, corn starch, and magnesium stearate was employed. The formulations were wet granulated with a 10% (wt/vol) starch paste in a high shear granulator and dried at 60°C in a convection tray dryer. The tablets were compressed on a Stokes B2 rotary tablet press running at 30 rpm. Each sample was scanned in reflectance mode in the wavelengths of the NIR region. Principal component analysis (PCA) of the NIR tablet spectra and the neat raw materials indicated that the scores of the first 2 principal components were highly correlated with the chemical and physical attributes. Based on the PCA model, the significant wavelengths for sulfamethazine are 1514, (1660–1694), 2000, 2050, 2150, 2175, 2225, and 2275 nm; for corn starch are 1974, 2100, and 2325 nm; and for magnesium stearate are 2325 and 2375 nm. In addition, the loadings show large negative peaks around the water band regions (≈1420 and 1940 nm), indicating that the partial least squares (PLS) models could be affected by product water content. A simple linear regression model was able to predict content uniformity with a correlation coefficient of 0.986 at 1656 nm; the use of a PLS regression model, with 3 factors, had anr ² of 0.9496 and a sandard error of calibration of 0.0316. The PLS validation set had anr ² of 0.9662 and a standard error of 0.0354. PLS calibration models, based on tablet absorbance data, could successfully predict tablet crushing strength and dissolution in spite of varying active pharmaceutical ingredient (API) levels. Prediction plots based on these PLS models yielded correlation coefficients of 0.84 and 0.92 on independent validation sets for crushing strength and Q₁₂₀ (percentage dissolved in 120 minutes), respectively. Published: September 20, 2005 The opinions expressed in this paper are of the authors' personal views. They do not necessarily reflect the views or policies of the FDA.     

应用近红外光谱估测小麦叶片氮含量

研究利用近红外光谱(near-infrared, NIR)和化学计量学方法估测小麦(Triticum aestivum)新鲜叶片和粉末状干叶中全氮含量的可行性, 并建立小麦叶片氮含量估测模型, 以期为小麦氮素营养的精确管理提供理论依据。以3个小麦田间试验观测资料为基础, 分别运用偏最小二乘法(partial least squares, PLS)、反向传播神经网络(back-propagation neural network, BPNN)和小波神经网络(wavelet neural network, WNN), 建立小麦叶片氮含量的鲜叶和粉末状干叶近红外光谱估测模型, 用随机选择的样品集对所建模型进行测试和检验。结果显示, 利用PLS、BPNN和WNN 3种方法构建的近红外光谱模型均能准确地估测小麦叶片氮含量, 其中基于BPNN和WNN的模型优于基于PLS的模型, 且以基于WNN的模型表现最好。对模型进行检验的结果显示, 粉末状干叶模型的预测均方根误差(RMSEP)分别为0.147、0.101和0.094, 鲜叶模型的RMSEP分别为0.216、0.175和0.169, 模型的相关系数均在0.84以上。因此, 利用近红外光谱估算小麦叶片氮素营养精确可行, 对其他作物的氮素营养估测提供了借鉴和参考。     

Gelation of high-methoxy pectin by enzymic de-esterification in the presence of calcium ions: a preliminary evaluation

Cohesive gels have been obtained by de-esterification of 1.0 wt % high-methoxy citrus pectin (degree of esterification ≈ 68%) in the presence of Ca²⁺ cations, using a commercial preparation (NovoShape) of fungal methyl esterase cloned from Aspergillus aculeatus. A convenient rate of network formation (gelation within ∼30 min) was achieved at an enzyme concentration of 0.2 PEU/g pectin. At a Ca²⁺-concentration of 40 mM and incubation temperature of 20 °C, severe syneresis (>7% of sample mass) was observed, but release of fluid decreased with decreasing concentration of Ca²⁺ and increasing temperature of incubation, becoming undetectable for 10 mM Ca²⁺ at 30 °C. Under these conditions, progressive development of solid-like character (storage modulus, G′) was observed during 160 min of enzymic de-esterification, and the mechanical spectrum recorded at the end of the incubation period had the form typical of a biopolymer gel. On subsequent heating to 70 °C, dissociation of the gel network (sigmoidal reduction in G′ and G″) was observed. At or above the midpoint temperature of this melting process (∼50 °C), there was no indication of gel formation on enzymic de-esterification (at 50 or 60 °C). At lower temperatures (20, 30 and 40 °C), the rate of gelation (assessed visually) showed no systematic increase as the incubation temperature was increased towards the temperature-optimum of the enzyme (∼50 °C). This unexpected behaviour is attributed to competition between faster de-esterification and slower formation of Ca²⁺-induced ‘egg-box’ junctions.     

Application of vibrational spectroscopy in the quality assessment of Buchu oil obtained from two commercially important Agathosma species (Rutaceae)

Quality assessment of natural raw materials and derived consumer products is often done using conventional analytical techniques such as liquid and gas chromatography which are expensive and time consuming. This paper reports on the use of vibrational spectroscopy techniques as possible alternatives for the rapid and inexpensive assessment of the quality of ‘buchu oil’ obtained from two South African species; Agathosma betulina and Agathosma crenulata belonging to the Rutaceae family. Samples of A. betulina (55) and A. crenulata (16) were collected from different natural localities and cultivation sites in South Africa. The essential oil was obtained by hydrodistillation and scanned on Near infrared (NIR), mid infrared (MIR) and Raman spectrometers. The spectral data obtained was processed using chemometric techniques and orthogonal partial least squares discriminant analysis (OPLS-DA) was used to clearly differentiate between A. betulina and A. crenulata. The OPLS-DA technique also proved to be a useful tool to identify wave regions that contain biomarkers (peaks) that contributed to the separation of the two species. The three spectroscopy techniques were also evaluated for their ability to accurately predict the percentage composition of seven major compounds that occur in A. betulina ‘buchu’ oil. Using GC–MS reference data, calibration models were developed for the MIR, NIR and Raman spectral data to predict/profile the major compounds in ‘buchu oil’. A comparison of the three spectroscopy techniques showed that MIR together with PLS algorithms produced the best model (R²X = 0.96; R²Y = 0.88 and Q²Ycum = 0.85) for the quantification of six of the seven major oil constituents. The MIR model showed high predictive power for pseudo-diosphenol (R² = 0.97), isomenthone (R² = 0.97), menthone (R² = 0.90), limonene (R² = 0.91), pulegone (R² = 0.96) and diosphenol (R² = 0.85). These results illustrate the potential of MIR spectroscopy as a rapid and inexpensive alternative to predict the major compounds in buchu oil.     

Environmentally friendly preparation of pectins from agricultural byproducts and their structural/rheological characterization

Apple pomace which is the main waste of fruit juice industry was utilized to extract pectins in an environmentally friendly way, which was then compared with chemically-extracted pectins. The water-based extraction with combined physical and enzymatic treatments produced pectins with 693.2 mg g⁻¹ galacturonic acid and 4.6% yield, which were less than those of chemically-extracted pectins. Chemically-extracted pectins exhibited lower degree of esterification (58%) than the pectin samples obtained by physical/enzymatic treatments (69%), which were also confirmed by FT-IR analysis. When subjected to steady-shear rheological conditions, both pectin solutions were shown to have shear-thinning properties. However, decreased viscosity was observed in the pectins extracted by combined physical/enzymatic methods which could be mainly attributed to the presence of more methyl esters, thus limiting polymer chain interactions. Moreover, the pectins which were extracted by combined physical/enzymatic treatments, showed less elastic properties under high shear rate conditions, compared to the chemically-extracted pectins.     

An efficient procedure for studying pectin structure which combines limited depolymerization and 13C NMR

A protocol for partial thermally-induced depolymerization of differently methoxylated pectin samples is described. The resulting macromolecules have been fully characterized with various complementary techniques, such as size exclusion chromatography (SEC), potentiometry, viscometry and ¹³C NMR. Optimum conditions afford samples at 50–80% yield with weight-average molecular weights in the 4 to 20 kDa range. The major fraction of these polysaccharides adopts the random-coil conformation and such samples are suitable for ¹³C NMR structural studies at room temperature. The methoxyl distributions of two apple pectin samples with a degree of esterification (DE) between 54 and 74% and a citrus pectin (DE, 72%) were shown to be random in nature, whereas that of a lightly methoxylated apple pectin (DE 39%) was partially blockwise. The carbon relaxation parameters of the depolymerized pectins attain asymptotic values for M_W > 4 kDa. The M_W values estimated from intrinsic viscosity data with the Mark-Houwink relationship reported for native pectins are in good agreement with those obtained by either end-group analysis (NMR) or SEC. Thus, all the physicochemical data indicate that the secondary structure of the isolated chains of depolymerized pectin is closely related to that of the parent polymers. Finally, pectinmethylesterase activity towards the depolymerized pectins was similar to that of the untreated samples. Received: 10 July 1997 / Accepted: 12 November 1997     

Calcium binding studies of peptides of human phospholipid scramblases 1 to 4 suggest that scramblases are new class of calcium binding proteins in the cell

Background

Phospholipid scramblases are a group of four homologous proteins conserved from C. elegans to human. In human, two members of the scramblase family, hPLSCR1 and hPLSCR3 are known to bring about Ca²⁺ dependent translocation of phosphatidylserine and cardiolipin respectively during apoptotic processes. However, affinities of Ca²⁺/Mg²⁺ binding to human scramblases and conformational changes taking place in them remains unknown.

Methods

In the present study, we analyzed the Ca²⁺ and Mg²⁺ binding to the calcium binding motifs of hPLSCR1–4 and hPLSCR1 by spectroscopic methods and isothermal titration calorimetry.

Results

The results in this study show that (i) affinities of the peptides are in the order hPLSCR1  > hPLSCR3 > hPLSCR2 > hPLSCR4 for Ca²⁺ and in the order hPLSCR1 > hPLSCR2 > hPLSCR3 > hPLSCR4 for Mg²⁺, (ii) binding of ions brings about conformational change in the secondary structure of the peptides. The affinity of Ca²⁺ and Mg²⁺ binding to protein hPLSCR1 was similar to that of the peptide I. A sequence comparison shows the existence of scramblase-like motifs among other protein families.

Conclusions

Based on the above results, we hypothesize that the Ca²⁺ binding motif of hPLSCR1 is a novel type of Ca²⁺ binding motif.

General significance

Our findings will be relevant in understanding the calcium dependent scrambling activity of hPLSCRs and their biological function.     

红外光谱技术在滇龙胆栽培方式选择上的应用

该研究采用傅里叶变换红外光谱结合化学计量学,对条播、撒播、剪根后移栽、扦插和剪枝后移栽的滇龙胆进行了分析,以筛选滇龙胆的最佳栽培方式。结果表明:(1)不同栽培方式的滇龙胆原始谱图在峰形、峰位和峰强上有一定差异;用小波去噪法对光谱进行优化处理并进行偏最小二乘判别分析(Partial least squares discriminant analysis,PLS-DA),能较好地区分不同栽培方式的滇龙胆样品,PLS-DA二维得分图显示同一栽培方式的样品聚在一起,表明相同栽培方式的滇龙胆化学组成和含量差异较小;播种滇龙胆样品(条播和撒播)距离较近,移栽滇龙胆样品(剪根、扦插和剪枝)距离较近,而播种和移栽滇龙胆样品距离较远,表明栽培方式对滇龙胆化学成分的积累有影响。(2)滇龙胆四种主要成分总含量大小依次是剪枝剪根撒播条播扦插,除剪根后移栽,剪枝后移栽滇龙胆中四种主要成分总含量显著高于其他栽培方式下的滇龙胆(P0.05),剪枝后移栽滇龙胆质量最佳。(3)以液相数据为参考值,采用正交信号校正—偏最小二乘回归模型预测不同栽培模式滇龙胆中龙胆苦苷、马钱苷酸、獐牙菜苦苷和当药苷的含量。校正集和验证集的决定系数(R2)均大于0.90,校正均方根误差、交叉验证均方差和预测均方根误差均小于1.65,模型相关性和预测效果好,该方法对红外光谱分析在中药领域的推广应用提供了参考。     

Validation of chemometric models for the determination of deoxynivalenol on maize by mid-infrared spectroscopy

Validation methods for chemometric models are presented, which are a necessity for the evaluation of model performance and prediction ability. Reference methods with known performance can be employed for comparison studies. Other validation methods include test set and cross validation, where some samples are set aside for testing purposes. The choice of the testing method mainly depends on the size of the original dataset. Test set validation is suitable for large datasets (>50), whereas cross validation is the best method for medium to small datasets (<50). In this study the K-nearest neighbour algorithm (KNN) was used as a reference method for the classification of contaminated and blank corn samples. A Partial least squares (PLS) regression model was evaluated using full cross validation. Mid-Infrared spectra were collected using the attenuated total reflection (ATR) technique and the fingerprint range (800–1800 cm⁻¹) of 21 maize samples that were contaminated with 300 – 2600 μg/kg deoxynivalenol (DON) was investigated. Separation efficiency after principal component analysis/cluster analysis (PCA/CA) classification was 100%. Cross validation of the PLS model revealed a correlation coefficient of r=0.9926 with a root mean square error of calibration (RMSEC) of 95.01. Validation results gave an r=0.8111 and a root mean square error of cross validation (RMSECV) of 494.5 was calculated. No outliers were reported. Presented at the 25^th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003     

Association between osteoporosis and polymorphisms of the bone Gla protein, estrogen receptor 1, collagen 1-A1 and calcitonin receptor genes in Turkish postmenopausal women

In this study, we have investigated the association between osteoporosis and osteocalcin (BGLAP) − 298 C>T, estrogen receptor 1 (ER1) 397 T>C, collagen type1 alpha 1 (Col1A1) 2046 G>T and calcitonin receptor (CALCR) 1340 T>C polymorphisms. Genomic DNA was obtained from 266 persons (158 osteoporotic and 108 healthy controls). Genomic DNA was extracted from EDTA-preserved peripheral venous blood of patients and controls by a salting-out method and analyzed by PCR-RFLP. As a result, there was no statistically significant difference in the genotype and allele frequencies of patients and controls for BGLAP − 298 C>T, Col1A1 2046 G>T, ER1 397 T>C and CALCR 1340 T>C polymorphisms. However, ER1 CC genotype compared with TT + TC genotypes was found to increase the two fold the risk of osteoporosis [p = 0.039, OR = 2.156, 95% CI (1.083–4.293)] and CALCR CC genotype compared with TT + TC genotypes was found to have protective effect against osteoporosis [p = 0.045, OR = 0.471, 95% CI (0.237–0.9372)]. In the combined genotype analysis, ER1/CALCR TCCC combined genotype was estimated to have protective effect against osteoporosis [p = 0.0125, OR = 0.323, 95% CI (0.1383–0.755)] whereas BGLAP/Col1A1 CCTT and ER1/CALCR CCTT combined genotypes were estimated as risk factors for osteoporosis in Turkish population (p = 0.027, p = 0.009 respectively).     

Pectin Methylesterase of Datura species,purification, and characterization from Datura stramoniumand its application

Pectin methylesterases (PME; EC 3.1.1.11) involved in de-esterification of pectin and have applicability in food, textiles, wines, pulp, and paper industries. In the present study, we compared PME activity of different parts of 3 Datura species and found that fruit coat showed maximum PME activity followed by leaf and seed. PME from leaves of D. stramonium (DsPME) was purified and characterized. DsPME showed optimum activity at 60 °C and pH 9 in the presence of 0.3 M NaCl. DsPME was stable at 70 °C and retained more than 40% activity after 60 min of incubation. However, enzyme activity completely abolished at 80 after 5 min of incubation. It follows Michaelis-Menten enzyme kinetics. Km and Vmax with citrus pectin were 0.008 mg/ml and 16.96 µmol/min, respectively. DsPME in combination with polygalactourenase (PGA) increased the clarity of orange, apple, pomegranate and pineapple juices by 2.9, 2.6, 2.3, and 3.6 fold, respectively in comparison to PGA alone. Due to very high de-esterification activity, easy denaturation and significant efficacy in incrementing clarification of fruit juice makes DsPME useful for industrial application.     

Sample-to-SNP kit: A reliable,easy and fast tool for the detection of HFE p.H63D and p.C282Y variations associated to hereditary hemochromatosis

Classical hereditary hemochromatosis involves the HFE-gene and diagnostic analysis of the DNA variants HFE p.C282Y (c.845G > A; rs1800562) and HFE p.H63D (c.187C > G; rs1799945). The affected protein alters the iron homeostasis resulting in iron overload in various tissues. The aim of this study was to validate the TaqMan-based Sample-to-SNP protocol for the analysis of the HFE-p.C282Y and p.H63D variants with regard to accuracy, usefulness and reproducibility compared to an existing SNP protocol. The Sample-to-SNP protocol uses an approach where the DNA template is made accessible from a cell lysate followed by TaqMan analysis. Besides the HFE-SNPs other eight SNPs were used as well. These SNPs were: Coagulation factor II-gene F2 c.20210G > A, Coagulation factor V-gene F5 p.R506Q (c.1517G > A; rs121917732), Mitochondria SNP: mt7028 G > A, Mitochondria SNP: mt12308 A > G, Proprotein convertase subtilisin/kexin type 9-gene PCSK9 p.R46L (c.137G > T), Plutathione S-transferase pi 1-gene GSTP1 p.I105V (c313A > G; rs1695), LXR g.-171 A > G, ZNF202 g.-118 G > T. In conclusion the Sample-to-SNP kit proved to be an accurate, reliable, robust, easy to use and rapid TaqMan-based SNP detection protocol, which could be quickly implemented in a routine diagnostic or research facility.     

Distribution of pectins in cell walls of maize coleoptiles and evidence against their involvement in auxin-induced extension growth

Summary Aiming to elucidate the possible involvement of pectins in auxin-mediated elongation growth the distribution of pectins in cell walls of maize coleoptiles was investigated. Antibodies against defined epitopes of pectin were used: JIM 5 recognizing pectin with a low degree of esterification, JIM 7 recognizing highly esterified pectin and 2F4 recognizing a pectin epitope induced by Ca²⁺. JIM 5 weakly labeled the outer third of the outer epidermal wall and the center of filled cell corners in the parenchyma. A similar labeling pattern was obtained with 2F4. In contrast, JIM 7 densely labeled the whole outer epidermal wall except the innermost layer, the middle lamellae, and the inner edges of open cell corners in the parenchyma. Enzymatic de-esterification with pectin methylesterase increased the labeling by JIM 5 and 2F4 substantially. A further increase of the labeling density by JIM 5 and 2F4 and an extension of the labeling over the whole outer epidermal wall could be observed after chemical de-esterification with alkali. This indicates that both methyl- and other esters exist in maize outer epidermal walls. Thus, in the growth-controlling outer epidermal wall a clear zonation of pectin fractions was observed: the outermost layer (about one third to one half of wall thickness) contains unesterified pectin epitopes, presumably cross-linked by Ca²⁺ extract. Tracer experiments with³H-myo-inositol showed rapid accumulation of tracer in all extractable pectin fractions and in a fraction tightly bound to the cell wall. A stimulatory effect of IAA on tracer incorporation could not be detected in any fraction. Summarizing the data a model of the pectin distribution in the cell walls of maize coleoptiles was developed and its implications for the mechanism of auxin-induced wall loosening are discussed.Abbreviations CDTA trans-1,2-diaminocyclohexane-N,N,N,N-tetraacetic acid - CWP cell-wall pellet - IAA indole-3-acetic acid - LSE low-salt extract - TCA trichloroacetic acid; Tris tris-(hydroxy-methyl)aminoethane     

Process analytical technology case study: Part II. Development and validation of quantitative near-infrared calibrations in support of a process analytical technology application for real-time release

This article is the second of a series of articles detailing the development of near-infrared (NIR) methods for solid dosage-form analysis. Experiments were conducted at the Duquesne University Center for Pharmaceutical Technology to demonstrate a method for developing and validating NIR models for the analysis of active pharmaceutical ingredient (API) content and hardness of a solid dosage form. Robustness and cross-validation testing were used to optimize the API content and hardness models. For the API content calibration, the optimal model was determined as multiplicative scatter correction with Savitsky-Golay first-derivative preprocessing followed by partial least-squares (PLS) regression including 4 latent variables. API content calibration achieved root mean squared error (RMSE) and root mean square error of cross validation (RMSECV) of 1.48 and 1.80 mg, respectively. PLS regression and baseline-fit calibration models were compared for the prediction of tablet hardness. Based on robustness testing, PLS regression was selected for the final hardness model, with RMSE and RMSECV of 8.1 and 8.8 N, respectively. Validation testing indicated that API content and hardness of production-scale tablets is predicted with root mean square error of prediction of 1.04 mg and 8.5 N, respectively. Explicit robustness testing for high-flux noise and wavelength uncertainty demonstrated the robustness of the API concentration calibration model with respect to normal instrument operating conditions. Published: October 6, 2005 The views presented in this article do not necessarily reflect those of the Food and Drug Administration.     

Prediction of moisture, calorific value, ash and carbon content of two dedicated bioenergy crops using near-infrared spectroscopy

The potential of near infrared spectroscopy in conjunction with partial least squares regression to predict Miscanthus xgiganteus and short rotation coppice willow quality indices was examined. Moisture, calorific value, ash and carbon content were predicted with a root mean square error of cross validation of 0.90% (R² = 0.99), 0.13 MJ/kg (R² = 0.99), 0.42% (R² = 0.58), and 0.57% (R² = 0.88), respectively. The moisture and calorific value prediction models had excellent accuracy while the carbon and ash models were fair and poor, respectively. The results indicate that near infrared spectroscopy has the potential to predict quality indices of dedicated energy crops, however the models must be further validated on a wider range of samples prior to implementation. The utilization of such models would assist in the optimal use of the feedstock based on its biomass properties.     

Quantitation of drug content in a low dosage formulation by transmission near infrared spectroscopy

A transmission near infrared (NIR) spectroscopic method has been developed for the nondestructive determination of drug content in tablets with less than 1% weight of active ingredient per weight of formulation (m/m) drug content. Tablets were manufactured with drug concentrations of ∼0.5%, 0.7%, and 1.0% (m/m) and ranging in drug content from 0.71 to 2.51 mg per tablet. Transmission NIR spectra were obtained for 110 tablets that constituted the training set for the calibration model developed with partial least squares regression. The reference method for the calibration model was a validated UV spectrophotometric method. Several data preprocessing methods were used to reduce the effect of scattering on the NIR spectra and base the calibration model on spectral changes related to the drug concentration changes. The final calibration model included the spectral range from 11 216 to 8662 cm⁻¹ the standard normal variate (SNV), and first derivative spectral pretreatments. This model was used to predict an independent set of 48 tablets with a root mean standard error of prediction (RMSEP) of 0.14 mg, and a bias of only −0.05 mg per tablet. The study showed that transmission NIR spectroscopy is a viable alternative for nondestructive testing of low drug content tablets, available for the analysis of large numbers of tablets during process development and as a tool to detect drug agglomeration and evaluate process improvement efforts. Published: March 24, 2006