ABSTRACT
Feasibility of a simple laser-induced breakdown spectroscopy (LIBS) device has been investigated for the analysis of Mg and Ca in edible salts. The LIBS spectrometer was assembled with a compact low-power diode-pumped solid-state laser (DPSSL) and a non-gated low-resolution handheld spectrometer. A simple sampling process was employed for on-site application. A piece of filter paper was dipped in the aqueous solution of a sample salt and dried for analysis using LIBS. Maintaining the sample surface height at the optimum position was critical to generate plasmas persistently due to the low pulse energy of the DPSSL. The varying height of the filter paper surface was monitored and compensated, while the sample stage was translated to collect spectra from different positions. The variation of line intensities of Mg and Ca could be attributed to the inhomogeneous distribution of dry residues. To correct this, the peak that consists of the Na(I) and C(II) lines at 568 nm was employed as a reference signal for intensity normalization of the analyte Mg(II) and Ca(II) lines. For edible salt products, the normalized Mg(II) and Ca(II) line intensities could be well correlated with the concentrations of Mg and Ca determined using inductively coupled plasma optical emission spectroscopy. Our results indicate that a simple LIBS device in combination with the simple sampling method is promising as an on-site salt quality assessment methodology.
ABSTRACT
Qualitative and quantitative determination of total arsenic content and arsenic species in rice is very important because rice is one of the main sources of human arsenic intake. However, extraction and determination of arsenic species in rice has been very difficult due to severe matrix interference. An alternative analytical method was developed in this study to determine arsenic species in rice by using ion chromatography coupled to inductively coupled plasma-mass spectrometry. Two internal standards were used. The first internal standard was injected before sample introduction to correct signal change with time. The second internal standard was spiked into the sample to reduce matrix interference. Using the developed method, recoveries of dimethylarsinic acid, monomethylarsonic acid, and inorganic arsenic compared to certified values (NIST SRM 1568b rice flour) were 116%, 107%, and 92%, respectively.
Subject(s)
Arsenic/analysis , Food Contamination/analysis , Oryza/chemistry , Chromatography , Chromatography, High Pressure Liquid , Humans , Mass Spectrometry , Spectrum AnalysisABSTRACT
BACKGROUND: The aim of this study was to observe clinical outcomes of the mother and her infant who were possibly exposed to high blood glucose at least 2-3 months in the early and midterm pregnancy by checking gestational weeks (GW) and the first HbA1c level at initial diagnosis of gestational diabetes (GDM). METHODS: A total of 107 GDM patients and their newborns were subject of this study. GDM patients were newly diagnosed at the Holy Family Hospital of Catholic University from January 2003 until December 2007 and continuously managed in the diabetes center. Patients medical records were retrospectively reviewed to evaluate GW and HbA1c level at the time of diagnosis, and clinical outcomes of mother and newborn baby. RESULTS: The proportion of subjects who had been diagnosed of having GDM according to GW was 7.5%, in less than 24th week of pregnancy; 55.1% in the 24-28th week; 28.0% in the 29-32nd week; and 9.4% 33rd week or more. There were 39 out of 107 subjects (36.4%) with HbA1c levels >or=6.5% and 26 out of 39 subjects (24.3%) with HbA1c levels >or=7.0%. In clinical outcomes of newborn by HbA1c levels, the frequency of delivery of large for gestational age (LGA) infant was higher in mothers diagnosed with GDM after 29th week of pregnancy or with HbA1c levels 7.0% or more (P<0.001). CONCLUSIONS: If the screening test for gestational DM was delayed, HbA1c level and the risk for LGA seemed to be higher, so it may be necessary to screen GDM no later than 24th week of pregnancy.
